The Angle of Trunk Rotation in School Children: A Study from an Idiopathic Scoliosis Screening. Prevalence and Optimal Age Screening Value

(1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2–3% of adolescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs are not very noticeable. That is why the primarily school-based screening for scoliosis is so important. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were elementary school students in the metropolitan area of Poland. The suspicion of IS was based on detection of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents were divided into two groups: Angle of trunk rotation (ATR) = 0–3º and ATR > 3º. Presented research using a referral criterion of 5º ATR showed that in the group of participants who had ATR > 3º the largest percentage of 5 degree values was recorded at the second and third measurement level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of girls (ATR = 0–3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than girls with ATR 0–3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4–6º trunk rotation), which can present mild scoliosis and those with a higher degree (7º trunk rotation) have lower body mass than girls within the norm.


Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for . Presented research using a referral criterion of 5 ic scoliosis is a deformity of the growing spine. It affects 2%-3% unknown. At the early stage of idiopathic scoliosis (IS), the signs why the primarily school-based screening for scoliosis is so a cross-sectional analysis of 6850 respondents. Participants were metropolitan area of Poland. The suspicion of IS was based on formity of the spine using scoliometer. (3) Results: Respondents gle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented f 5º ATR showed that in the group of participants who had ATR gree values was recorded at the second and third measurement spectively). Analyzing the differences between the two groups of istically significant differences were recorded between 9 and 11 h ATR > 3º at all measuring levels are significantly slimmer than ons: Age; sex, and risk of developing angle of trunk rotation are thoracic (level 2) and thoraco-lumbar (level 3) level of measuring st differentiating in the diagnosis of scoliosis. Girls with a lower unk rotation), which can present mild scoliosis and those with a ave lower body mass than girls within the norm.
gle of trunk rotation; optimal age screening; prevalence; school most common pediatric musculoskeletal disorder that causes a spine [1]. It refers to about 2-3% of the adolescent population [2]. nown, researchers have focused on genetic factors, metabolic and ymmetry with mechanical and connective tissue abnormalities. A obb angle of 10º or more. As is generally known, IS progression rls than boys, especially during puberty [3]. The optimal age for ate. The Scoliosis Research Society has recommended screening d screening boys at the age 13 or 14 years [4]. Moreover, in recent ty and the American Academy of Orthopedic Society of North emy of Pediatrics have endorsed school scoliosis screening okyo suggest that school screening for scoliosis is effective for

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that ca three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent populat Although its etiology is largely unknown, researchers have focused on genetic factors, metabo hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormal common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progr appears more frequently among girls than boys, especially during puberty [3]. The optimal scoliosis screening is still under debate. The Scoliosis Research Society has recommended scr girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in years, the Scoliosis Research Society and the American Academy of Orthopedic Society of America, and the American Academy of Pediatrics have endorsed school scoliosis scr programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effect a deformity of the growing spine. It affects 2%-3% t the early stage of idiopathic scoliosis (IS), the signs imarily school-based screening for scoliosis is so nal analysis of 6850 respondents. Participants were area of Poland. The suspicion of IS was based on e spine using scoliometer. (3) Results: Respondents otation (ATR) = 0 º -3º and ATR > 3º. Presented wed that in the group of participants who had ATR as recorded at the second and third measurement nalyzing the differences between the two groups of ficant differences were recorded between 9 and 11 all measuring levels are significantly slimmer than , and risk of developing angle of trunk rotation are l 2) and thoraco-lumbar (level 3) level of measuring ing in the diagnosis of scoliosis. Girls with a lower ), which can present mild scoliosis and those with a dy mass than girls within the norm. rotation; optimal age screening; prevalence; school n pediatric musculoskeletal disorder that causes a efers to about 2-3% of the adolescent population [2]. hers have focused on genetic factors, metabolic and mechanical and connective tissue abnormalities. A 10º or more. As is generally known, IS progression , especially during puberty [3]. The optimal age for liosis Research Society has recommended screening oys at the age 13 or 14 years [4]. Moreover, in recent merican Academy of Orthopedic Society of North iatrics have endorsed school scoliosis screening t that school screening for scoliosis is effective for ), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3 ic scoliosis is a deformity of the growing spine. It affects 2%-3% nknown. At the early stage of idiopathic scoliosis (IS), the signs why the primarily school-based screening for scoliosis is so cross-sectional analysis of 6850 respondents. Participants were metropolitan area of Poland. The suspicion of IS was based on ormity of the spine using scoliometer. (3) Results: Respondents le of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented f 5º ATR showed that in the group of participants who had ATR ree values was recorded at the second and third measurement pectively). Analyzing the differences between the two groups of stically significant differences were recorded between 9 and 11 ATR > 3º at all measuring levels are significantly slimmer than ns: Age; sex, and risk of developing angle of trunk rotation are horacic (level 2) and thoraco-lumbar (level 3) level of measuring t differentiating in the diagnosis of scoliosis. Girls with a lower unk rotation), which can present mild scoliosis and those with a ve lower body mass than girls within the norm. gle of trunk rotation; optimal age screening; prevalence; school ost common pediatric musculoskeletal disorder that causes a pine [1]. It refers to about 2-3% of the adolescent population [2]. own, researchers have focused on genetic factors, metabolic and mmetry with mechanical and connective tissue abnormalities. A bb angle of 10º or more. As is generally known, IS progression ls than boys, especially during puberty [3]. The optimal age for ate. The Scoliosis Research Society has recommended screening screening boys at the age 13 or 14 years [4]. Moreover, in recent y and the American Academy of Orthopedic Society of North emy of Pediatrics have endorsed school scoliosis screening okyo suggest that school screening for scoliosis is effective for at all measuring levels are significantly slimmer than girls with ATR 0-3

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that ca three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent populat Although its etiology is largely unknown, researchers have focused on genetic factors, metabo hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormal common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progr appears more frequently among girls than boys, especially during puberty [3]. The optimal scoliosis screening is still under debate. The Scoliosis Research Society has recommended scr girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in years, the Scoliosis Research Society and the American Academy of Orthopedic Society of America, and the American Academy of Pediatrics have endorsed school scoliosis scr programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effect ; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4)(5)(6)  Published: date eformity of the growing spine. It affects 2%-3% early stage of idiopathic scoliosis (IS), the signs rily school-based screening for scoliosis is so analysis of 6850 respondents. Participants were ea of Poland. The suspicion of IS was based on ine using scoliometer. (3) Results: Respondents ion (ATR) = 0 º -3º and ATR > 3º. Presented that in the group of participants who had ATR recorded at the second and third measurement yzing the differences between the two groups of nt differences were recorded between 9 and 11 measuring levels are significantly slimmer than d risk of developing angle of trunk rotation are and thoraco-lumbar (level 3) level of measuring in the diagnosis of scoliosis. Girls with a lower hich can present mild scoliosis and those with a ass than girls within the norm.
tion; optimal age screening; prevalence; school ediatric musculoskeletal disorder that causes a s to about 2-3% of the adolescent population [2]. s have focused on genetic factors, metabolic and echanical and connective tissue abnormalities. A or more. As is generally known, IS progression ecially during puberty [3]. The optimal age for s Research Society has recommended screening trunk rotation), which can present mild scoliosis and those with a higher degree (7

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2] Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age fo scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10 (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% olescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs not very noticeable. That is why the primarily school-based screening for scoliosis is so rtant.
(2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were entary school students in the metropolitan area of Poland. The suspicion of IS was based on ction of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented rch using a referral criterion of 5º ATR showed that in the group of participants who had ATR the largest percentage of 5 degree values was recorded at the second and third measurement l of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 s of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring e spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower ee of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a er degree (7º trunk rotation) have lower body mass than girls within the norm.
or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for early detection; 2 of 9 however, it is first necessary to review and optimize the target groups [7]. Some countries, like the USA and Hong Kong, report that the school-based screening program is costly and inefficient [2]. The Canadian Task Force on Periodic Health examination, the British Orthopedic Association, and the British Scoliosis Society do not recommend screening [2]. These differences in expert opinion are constantly subject to discussion and research. School screening has generally been performed between ages 10 to 14 years. What is certain, early diagnosis and appropriate therapeutic methods will help to inhibit the progressive changes in the musculoskeletal system [8]. Detection during the initial stage when the deformity is unnoticeable offers an opportunity of non-surgical treatment. That is why scoliosis screening is so important in primarily preventing deformity progression. The basic method for scoliosis detection in school screening programs is examination by using a scoliometer. It has not been designed to be a diagnostic method but to select children with high probability of occurrence of idiopathic scoliosis out of the healthy population [9,10]. The implication the scoliometer measurement of the angle of trunk rotation with combination of the Adam Forward Bending Test has been shown the easiest, non-invasive measure of trunk deformity [11,12]. Scoliometer is an instrument that measures axial trunk rotation in individuals with scoliosis. Frequency analysis revealed relatively good specificity, sensitivity, and predictive capability. Coelho et al. [13] noted the correlation between the scoliometer measurement and the radiographic analysis (r = 0.7 with p < 0.05) in their research. The use of this tool as a screening device is appropriate [14,15]. It should be noted that adolescent idiopathic scoliosis (AIS) develop at the age of 11-18 years and most often occurs among IS (comprising 85-90% of cases of IS in children). According to Konieczny et al. [16], AIS occurs in the general population in a wide range from 0.47% to 5%.
The purpose of this study was to (1) present epidemiological findings according to the age and gender of the participants, (2) to assess the magnitude of trunk asymmetry, (3) find the optimal age screening, (4) and to observe the age of children, especially girls of the highest IS risk, which should not be overlooked in school scoliosis screening.

Materials and Methods
We applied a cross-sectional, observational study. The study was approved by The Poznan University of Medical Sciences Bioethics Committee under process number 892/12. After the previous physiotherapy training, all the methodological guidelines conducted in the study were strictly followed. One month before beginning the data collection, the screeners were trained to use the Bunnell scoliometer.

Sample Size
The study involved 6850 angle of trunk rotation analyses volunteers (n = 6850) who met the inclusion criteria. A total of 65 schools in Poznan (Poland) responded to the study announcement. The inclusion criteria for the examination were the following: Only healthy volunteers between 9 and 13 years of age who took part in the school's regular physical activity class during the last year were recruited. In addition, the participants had no history of surgery on the back or lower limbs, and a lower limb length discrepancy smaller than 2.5 cm. Parents and legal guardians of all participants signed an informed consent form prior to participation. The volunteers were sought among all the primary schools in Poznan.

Research Procedure
The male volunteers participated in the examination bare-chested. The female volunteers had their hair tied up and wore a customized backless t-shirt to provide full view of their back. After collecting anthropometric measures, examinations of angle of trunk rotation were done using the Bunnell scoliometer. The screening test was quick, easy to perform and repeat, non-invasive, and safe. The examination procedure was carried out in Adam Forward Bending Test position and also allowed to rate the vertebral rotation-the angle of trunk rotation (ATR) [17]. Through palpation, the spinous processes T 1 to L 5 and posterior iliac superior spine were located and marked using easy-blend and anti-allergic markers. The measurement was performed in the free standing position during bending (Adams forward test) at three levels: Level 1-proximal thoracic (T 1 -T 4 ), level 2-main thoracic (T 5 -T 12 ), and level 3-lumbar (T 12 -L 4 ) [18,19]. The patients bent their trunk forward until it was parallel to the ground, keeping the palms of their hands together. The volunteers kept their feet approximately perpendicular to the iliac junction line. For all of the sections, an ATR value from zero to 3 was considered the norm, while values above 3 were considered to be outside the norm. The reason of that division is to present the results according to the Bunnell classification percentage of children who are in the range of ATR 4-6 with a 5 degree value. According to Bunnell, these children should be re-examined for scoliosis within 4-12 months, while according to Coelho it is highly probable to diagnose scoliosis in that moment and therapeutic treatment should start earlier [13,20].
Initially, muscle extensor spinae was examined on three levels. Measurements of the angle of trunk rotation were performed once using the qualified assessors. The examination took place in separate bright rooms with adequate thermal conditions during school hours.
Children with ATR between 4-6 degrees were also strongly suspected in clinical trials for increased trunk asymmetry. Therefore, these volunteers were referred for follow-up examinations within three months.
All statistical analysis was performed using Statistica 8 Software. The data for scoliometric analyses were correlated using Pearson correlation coefficients with a level of significance p < 0.0001. This study used independent Z-tests to analyze the average values of measurement items between groups according to age, gender, angle of trunk rotation, and body mass. These groups were used to investigate risk factors of scoliosis, and comparatively analyzed angle of trunk rotation with age, gender, and body mass (ANOVA). We finally checked the distribution of percentage of children who had ATR = 5 • in both groups (ATR = 0-3 That is why the primarily school-based screening for scoliosis is so ethods: This was a cross-sectional analysis of 6850 respondents. Participants were ol students in the metropolitan area of Poland. The suspicion of IS was based on ee-dimensional deformity of the spine using scoliometer. (3) Results: Respondents to two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented referral criterion of 5º ATR showed that in the group of participants who had ATR percentage of 5 degree values was recorded at the second and third measurement e (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of 3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are ociated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring ears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a º trunk rotation) have lower body mass than girls within the norm. pathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school coliosis (IS) is the most common pediatric musculoskeletal disorder that causes a l deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. logy is largely unknown, researchers have focused on genetic factors, metabolic and ers, and growth asymmetry with mechanical and connective tissue abnormalities. A tic criterion is a Cobb angle of 10º or more. As is generally known, IS progression quently among girls than boys, especially during puberty [3]. The optimal age for g is still under debate. The Scoliosis Research Society has recommended screening 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% scents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs very noticeable. That is why the primarily school-based screening for scoliosis is so nt. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were tary school students in the metropolitan area of Poland. The suspicion of IS was based on n of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents vided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented h using a referral criterion of 5º ATR showed that in the group of participants who had ATR largest percentage of 5 degree values was recorded at the second and third measurement the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of TR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 f age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than ith ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are sely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring pine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a degree (7º trunk rotation) have lower body mass than girls within the norm. rds: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school n uction pathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a ensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. h its etiology is largely unknown, researchers have focused on genetic factors, metabolic and l disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression more frequently among girls than boys, especially during puberty [3]. The optimal age for screening is still under debate. The Scoliosis Research Society has recommended screening e age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent e Scoliosis Research Society and the American Academy of Orthopedic Society of North , and the American Academy of Pediatrics have endorsed school scoliosis screening s [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for ) and analyzed the optimal age screening.

Demographics
Full data were available on 6850 volunteers: 3440 females and 3410 males. The main anthropometric characteristics and the value of trunk asymmetry are described in Table 1. As shown in Table 2, the division of research material was split into two groups: Participants (girls and boys) with ATR = 0-3 (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% scents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs very noticeable. That is why the primarily school-based screening for scoliosis is so nt. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were ary school students in the metropolitan area of Poland. The suspicion of IS was based on n of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents ided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented using a referral criterion of 5º ATR showed that in the group of participants who had ATR largest percentage of 5 degree values was recorded at the second and third measurement he spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of R = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than h ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are sely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring ine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower f trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a egree (7º trunk rotation) have lower body mass than girls within the norm. ds: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% of adolescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs are not very noticeable. That is why the primarily school-based screening for scoliosis is so important. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were elementary school students in the metropolitan area of Poland. The suspicion of IS was based on detection of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents were divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented research using a referral criterion of 5º ATR showed that in the group of participants who had ATR > 3º the largest percentage of 5 degree values was recorded at the second and third measurement level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than girls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a higher degree (7º trunk rotation) have lower body mass than girls within the norm.

ngle of Trunk Rotation in School Children
Keywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school children (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% lescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs t very noticeable. That is why the primarily school-based screening for scoliosis is so tant. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were tary school students in the metropolitan area of Poland. The suspicion of IS was based on ion of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents ivided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented ch using a referral criterion of 5º ATR showed that in the group of participants who had ATR e largest percentage of 5 degree values was recorded at the second and third measurement f the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of TR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 f age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than ith ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are losely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a degree (7º trunk rotation) have lower body mass than girls within the norm. ords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school criterion. The analysis of trunk asymmetry was analyzed on three levels of the spine: Proximal thoracic, main thoracic, and lumbar. The maximal ATR value was retained. Abstract: (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% of adolescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs are not very noticeable. That is why the primarily school-based screening for scoliosis is so important. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were elementary school students in the metropolitan area of Poland. The suspicion of IS was based on detection of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents were divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented research using a referral criterion of 5º ATR showed that in the group of participants who had ATR > 3º the largest percentage of 5 degree values was recorded at the second and third measurement level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than girls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a higher degree (7º trunk rotation) have lower body mass than girls within the norm.
Keywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school children

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% s; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs noticeable. That is why the primarily school-based screening for scoliosis is so ) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were chool students in the metropolitan area of Poland. The suspicion of IS was based on three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented g a referral criterion of 5º ATR showed that in the group of participants who had ATR st percentage of 5 degree values was recorded at the second and third measurement ine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than R 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower nk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a e (7º trunk rotation) have lower body mass than girls within the norm. diopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school n c scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a onal deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. tiology is largely unknown, researchers have focused on genetic factors, metabolic and rders, and growth asymmetry with mechanical and connective tissue abnormalities. A nostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression frequently among girls than boys, especially during puberty [3]. The optimal age for ning is still under debate. The Scoliosis Research Society has recommended screening of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent liosis Research Society and the American Academy of Orthopedic Society of North the American Academy of Pediatrics have endorsed school scoliosis screening ]. Researchers from Tokyo suggest that school screening for scoliosis is effective for , the largest percentage of 5

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for values was recorded at the second measurement level of the spine (31.5%). A high percentage a five-degree trunk rotation angle was also recorded at level 3 (33.2%) and the lowest at the first level 28.9%, respectively. Therefore, the percentage of five-degree values among the entire population exceeded over 3% in the second measurement level.

Prevalence
As shown in Figure 1, it can be observed that on the first level of measurement, ATR increased in girls with age (p < 0.0001). Statistically significant difference (p = 0.0829) between ATR values were noted in girls and boys in the 13-year group. Analyzing the differences between the two groups of girls (ATR Presented TR showed that in the group of participants who had ATR alues was recorded at the second and third measurement ely). Analyzing the differences between the two groups of y significant differences were recorded between 9 and 11 > 3º at all measuring levels are significantly slimmer than ge; sex, and risk of developing angle of trunk rotation are ic (level 2) and thoraco-lumbar (level 3) level of measuring rentiating in the diagnosis of scoliosis. Girls with a lower otation), which can present mild scoliosis and those with a wer body mass than girls within the norm. trunk rotation; optimal age screening; prevalence; school common pediatric musculoskeletal disorder that causes a [1]. It refers to about 2-3% of the adolescent population [2]. researchers have focused on genetic factors, metabolic and try with mechanical and connective tissue abnormalities. A gle of 10º or more. As is generally known, IS progression n boys, especially during puberty [3]. pathic scoliosis is a deformity of the growing spine. It affects 2%-3% still unknown. At the early stage of idiopathic scoliosis (IS), the signs t is why the primarily school-based screening for scoliosis is so as a cross-sectional analysis of 6850 respondents. Participants were the metropolitan area of Poland. The suspicion of IS was based on l deformity of the spine using scoliometer. (3) Results: Respondents Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented ion of 5º ATR showed that in the group of participants who had ATR 5 degree values was recorded at the second and third measurement , respectively). Analyzing the differences between the two groups of statistically significant differences were recorded between 9 and 11 with ATR > 3º at all measuring levels are significantly slimmer than lusions: Age; sex, and risk of developing angle of trunk rotation are ain thoracic (level 2) and thoraco-lumbar (level 3) level of measuring most differentiating in the diagnosis of scoliosis. Girls with a lower 6º trunk rotation), which can present mild scoliosis and those with a n) have lower body mass than girls within the norm.
s; angle of trunk rotation; optimal age screening; prevalence; school the most common pediatric musculoskeletal disorder that causes a the spine [1]. It refers to about 2-3% of the adolescent population [2]. unknown, researchers have focused on genetic factors, metabolic and asymmetry with mechanical and connective tissue abnormalities. A a Cobb angle of 10º or more. As is generally known, IS progression g girls than boys, especially during puberty [3]. The optimal age for debate. The Scoliosis Research Society has recommended screening s and screening boys at the age 13 or 14 years [4]. Moreover, in recent ociety and the American Academy of Orthopedic Society of North cademy of Pediatrics have endorsed school scoliosis screening m Tokyo suggest that school screening for scoliosis is effective for ), statistically significant differences were recorded between 9 and 13 years. Girls were noted with a p-value of p = 0.0006.  Among participants who had ATR > 3º, the largest percentage of 5º values was recorded at the second measurement level of the spine (31.5%). A high percentage a five-degree trunk rotation angle was also recorded at level 3 (33.2%) and the lowest at the first level 28.9%, respectively. Therefore, the percentage of five-degree values among the entire population exceeded over 3% in the second measurement level. Figure 1. ATR absolute values-comparison of differences between age and sex (level 1). * * In the upper part of the bar are presented children whose ATR is more than 3º, in the lower part ATR = 0º-3º (Figure 1,2,3).

Prevalence
As shown in Figure 1, it can be observed that on the first level of measurement, ATR increased in girls with age (p < 0.0001). Statistically significant difference (p = 0.0829) between ATR values were noted in girls and boys in the 13-year group. Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 13 years. Girls were noted with a p-value of p = 0.0006. Respondents were divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented research using a referral criterion of 5º ATR showed that in the group of participants who had ATR > 3º the largest percentage of 5 degree values was recorded at the second and third measurement level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than girls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a higher degree (7º trunk rotation) have lower body mass than girls within the norm.
Keywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school children

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a , in the lower part ATR = 0-3

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes (Figures 1-3).
As shown in Figure 2, at level 2, there was a noticeable increase in percentage of girls who had ATR Presented ed that in the group of participants who had ATR as recorded at the second and third measurement alyzing the differences between the two groups of icant differences were recorded between 9 and 11 all measuring levels are significantly slimmer than and risk of developing angle of trunk rotation are 2) and thoraco-lumbar (level 3) level of measuring ng in the diagnosis of scoliosis. Girls with a lower which can present mild scoliosis and those with a y mass than girls within the norm.
otation; optimal age screening; prevalence; school in all age groups. Statistically significant differences were found in the group of 12-year girls and boys with p = 0.0019. Analyzing the differences between the two groups of girls (ATR = 0-3 Respo were divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Pre research using a referral criterion of 5º ATR showed that in the group of participants who ha > 3º the largest percentage of 5 degree values was recorded at the second and third measur level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two gro girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimme girls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotat very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of mea of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a degree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those higher degree (7º trunk rotation) have lower body mass than girls within the norm.

The Angle of Trunk Rotation in School Children: A Study from an Idiopathic Scoliosis Screening. Prevalence and Optimal Age Screening
Keywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; children Presented ed that in the group of participants who had ATR as recorded at the second and third measurement alyzing the differences between the two groups of icant differences were recorded between 9 and 11 all measuring levels are significantly slimmer than and risk of developing angle of trunk rotation are 2) and thoraco-lumbar (level 3) level of measuring ng in the diagnosis of scoliosis. Girls with a lower , which can present mild scoliosis and those with a y mass than girls within the norm.
otation; optimal age screening; prevalence; school ), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023. As shown in Figure 2, at level 2, there was a noticeable increase in percentage of girls who had ATR > 3º in all age groups. Statistically significant differences were found in the group of 12-year girls and boys with p = 0.0019. Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023. As shown in Figure 3, the third level of measurement also presented the increase in the percentage of girls who had ATR > 3º in all age groups (p < 0.0001). Statistically significant difference (p = 0.0050; p = 0.0073) between ATR values were noted in girls and boys in the 11 and 12-year group. Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023.  As shown in Figure 3, the third level of measurement also presented the increase in the percentage of girls who had ATR > 3 athic scoliosis is a deformity of the growing spine. It affects 2%-3% ill unknown. At the early stage of idiopathic scoliosis (IS), the signs is why the primarily school-based screening for scoliosis is so as a cross-sectional analysis of 6850 respondents. Participants were the metropolitan area of Poland. The suspicion of IS was based on deformity of the spine using scoliometer. (3) Results: Respondents ngle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented n of 5º ATR showed that in the group of participants who had ATR degree values was recorded at the second and third measurement respectively). Analyzing the differences between the two groups of tatistically significant differences were recorded between 9 and 11 ith ATR > 3º at all measuring levels are significantly slimmer than sions: Age; sex, and risk of developing angle of trunk rotation are in thoracic (level 2) and thoraco-lumbar (level 3) level of measuring ost differentiating in the diagnosis of scoliosis. Girls with a lower º trunk rotation), which can present mild scoliosis and those with a ) have lower body mass than girls within the norm. angle of trunk rotation; optimal age screening; prevalence; school he most common pediatric musculoskeletal disorder that causes a he spine [1]. It refers to about 2-3% of the adolescent population [2]. nknown, researchers have focused on genetic factors, metabolic and asymmetry with mechanical and connective tissue abnormalities. A Cobb angle of 10º or more. As is generally known, IS progression girls than boys, especially during puberty [3]. The optimal age for debate. The Scoliosis Research Society has recommended screening and screening boys at the age 13 or 14 years [4]. Moreover, in recent ciety and the American Academy of Orthopedic Society of North cademy of Pediatrics have endorsed school scoliosis screening Tokyo suggest that school screening for scoliosis is effective for (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% adolescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs e not very noticeable. That is why the primarily school-based screening for scoliosis is so portant. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were mentary school students in the metropolitan area of Poland. The suspicion of IS was based on tection of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents ere divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented search using a referral criterion of 5º ATR showed that in the group of participants who had ATR 3º the largest percentage of 5 degree values was recorded at the second and third measurement el of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of rls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 ars of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than rls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are ry closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower gree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a gher degree (7º trunk rotation) have lower body mass than girls within the norm. ywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school ildren ntroduction Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a e-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. hough its etiology is largely unknown, researchers have focused on genetic factors, metabolic and monal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A mon diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression ears more frequently among girls than boys, especially during puberty [3]. The optimal age for liosis screening is still under debate. The Scoliosis Research Society has recommended screening s at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent rs, the Scoliosis Research Society and the American Academy of Orthopedic Society of North erica, and the American Academy of Pediatrics have endorsed school scoliosis screening grams [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for ), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023. As shown in Figure 2, at level 2, there was a noticeable increase in percentage of girls who had ATR > 3º in all age groups. Statistically significant differences were found in the group of 12-year girls and boys with p = 0.0019. Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023. As shown in Figure 3, the third level of measurement also presented the increase in the percentage of girls who had ATR > 3º in all age groups (p < 0.0001). Statistically significant difference (p = 0.0050; p = 0.0073) between ATR values were noted in girls and boys in the 11 and 12-year group. Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). The difference between 9 and 13 years girls was noted with a p-value of p = 0.0023.

The Difference and Comparison in ATR Values Between Age and Sex
As shown in Figure 4, at all measurement levels in the range 0-3

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2].
, girls had higher values of trunk rotation than boys (level 1: F 1-6594 = 86.94; p < 0.0001, level 2: F 1-6121 = 28.113; p < 0.0001, level 3: F 1-6367 = 50.501; p < 0.0001). ATR increased between the age of 9 and 13 years except the second level of measurement where girls and boys did not differ (significant effect of time, level 1: Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% s; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs noticeable. That is why the primarily school-based screening for scoliosis is so ) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were chool students in the metropolitan area of Poland. The suspicion of IS was based on hree-dimensional deformity of the spine using scoliometer. (3) Results: Respondents into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented g a referral criterion of 5º ATR showed that in the group of participants who had ATR st percentage of 5 degree values was recorded at the second and third measurement ine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than R 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are ssociated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring ppears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower nk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a e (7º trunk rotation) have lower body mass than girls within the norm. iopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school were no changes in ATR between girls and boys (level:  Figure 4. Two-factor analysis of variance to assess differences in ATR value.* * Lines on charts with full bullet points means girls and with empty bullet points boys.

The Difference and Comparison in Body Weight Values Between Age and Sex
As shown in Figure 5, it is worth mentioning that girls with ATR > (1) Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% of adolescents; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs are not very noticeable. That is why the primarily school-based screening for scoliosis is so important. (2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were elementary school students in the metropolitan area of Poland. The suspicion of IS was based on detection of three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents were divided into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented research using a referral criterion of 5º ATR showed that in the group of participants who had ATR > 3º the largest percentage of 5 degree values was recorded at the second and third measurement level of the spine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of girls (ATR = 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 years of age (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than girls with ATR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring of the spine appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower degree of trunk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a higher degree (7º trunk rotation) have lower body mass than girls within the norm. Keywords: idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school children

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for at all measuring levels are significantly slimmer than girls with ATR 0-3 s. Public Health 2019 Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% ts; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs y noticeable. That is why the primarily school-based screening for scoliosis is so 2) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were school students in the metropolitan area of Poland. The suspicion of IS was based on three-dimensional deformity of the spine using scoliometer. (3) Results: Respondents d into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented ng a referral criterion of 5º ATR showed that in the group of participants who had ATR est percentage of 5 degree values was recorded at the second and third measurement pine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 (p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than TR 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring appears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower nk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a e (7º trunk rotation) have lower body mass than girls within the norm. idiopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school n ic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a ional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. tiology is largely unknown, researchers have focused on genetic factors, metabolic and orders, and growth asymmetry with mechanical and connective tissue abnormalities. A nostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression frequently among girls than boys, especially during puberty [3]. The optimal age for ning is still under debate. The Scoliosis Research Society has recommended screening e of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent liosis Research Society and the American Academy of Orthopedic Society of North the American Academy of Pediatrics have endorsed school scoliosis screening ]. Researchers from Tokyo suggest that school screening for scoliosis is effective for  athic scoliosis is a deformity of the growing spine. It affects 2%-3% ill unknown. At the early stage of idiopathic scoliosis (IS), the signs is why the primarily school-based screening for scoliosis is so as a cross-sectional analysis of 6850 respondents. Participants were he metropolitan area of Poland. The suspicion of IS was based on deformity of the spine using scoliometer. (3) Results: Respondents ngle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented n of 5º ATR showed that in the group of participants who had ATR degree values was recorded at the second and third measurement respectively). Analyzing the differences between the two groups of tatistically significant differences were recorded between 9 and 11 ith ATR > 3º at all measuring levels are significantly slimmer than sions: Age; sex, and risk of developing angle of trunk rotation are is presented with solid lines, section of ATR > 3

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for Background: Idiopathic scoliosis is a deformity of the growing spine. It affects 2%-3% s; yet its cause is still unknown. At the early stage of idiopathic scoliosis (IS), the signs noticeable. That is why the primarily school-based screening for scoliosis is so ) Methods: This was a cross-sectional analysis of 6850 respondents. Participants were chool students in the metropolitan area of Poland. The suspicion of IS was based on hree-dimensional deformity of the spine using scoliometer. (3) Results: Respondents into two groups: Angle of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented g a referral criterion of 5º ATR showed that in the group of participants who had ATR st percentage of 5 degree values was recorded at the second and third measurement ine (30.5%, 31.1%, respectively). Analyzing the differences between the two groups of 0º-3º, ATR > 3º), statistically significant differences were recorded between 9 and 11 p = 0.0388). Girls with ATR > 3º at all measuring levels are significantly slimmer than R 0º-3º; (4) Conclusions: Age; sex, and risk of developing angle of trunk rotation are ssociated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring ppears to be the most differentiating in the diagnosis of scoliosis. Girls with a lower nk deformity (4º-6º trunk rotation), which can present mild scoliosis and those with a (7º trunk rotation) have lower body mass than girls within the norm.
iopathic scoliosis; angle of trunk rotation; optimal age screening; prevalence; school scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a nal deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. iology is largely unknown, researchers have focused on genetic factors, metabolic and rders, and growth asymmetry with mechanical and connective tissue abnormalities. A ostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression frequently among girls than boys, especially during puberty [3]. The optimal age for ing is still under debate. The Scoliosis Research Society has recommended screening of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent liosis Research Society and the American Academy of Orthopedic Society of North the American Academy of Pediatrics have endorsed school scoliosis screening . Researchers from Tokyo suggest that school screening for scoliosis is effective for

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for as the criteria for referral. Bunnell  oliosis is a deformity of the growing spine. It affects 2%-3% own. At the early stage of idiopathic scoliosis (IS), the signs the primarily school-based screening for scoliosis is so s-sectional analysis of 6850 respondents. Participants were opolitan area of Poland. The suspicion of IS was based on ty of the spine using scoliometer. (3) Results: Respondents trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented TR showed that in the group of participants who had ATR values was recorded at the second and third measurement ively). Analyzing the differences between the two groups of lly significant differences were recorded between 9 and 11 > 3º at all measuring levels are significantly slimmer than ge; sex, and risk of developing angle of trunk rotation are cic (level 2) and thoraco-lumbar (level 3) level of measuring erentiating in the diagnosis of scoliosis. Girls with a lower otation), which can present mild scoliosis and those with a wer body mass than girls within the norm. f trunk rotation; optimal age screening; prevalence; school common pediatric musculoskeletal disorder that causes a [1]. It refers to about 2-3% of the adolescent population [2]. , researchers have focused on genetic factors, metabolic and try with mechanical and connective tissue abnormalities. A ngle of 10º or more. As is generally known, IS progression n boys, especially during puberty [3]. The optimal age for he Scoliosis Research Society has recommended screening ening boys at the age 13 or 14 years [4]. Moreover, in recent d the American Academy of Orthopedic Society of North of Pediatrics have endorsed school scoliosis screening suggest that school screening for scoliosis is effective for angle of trunk rotation as a criteria for referral to decrease the number of false positives and recommended that children with a lower degree of trunk deformity (4-6

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for trunk rotation), which can present mild scoliosis, should be rescreened in 4-12 months [20,22].
Optimal management of idiopathic scoliosis requires prevention rather than treatment of disease. The presented research using a referral criterion of 5

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent years, the Scoliosis Research Society and the American Academy of Orthopedic Society of North America, and the American Academy of Pediatrics have endorsed school scoliosis screening programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effective for scoliosis is a deformity of the growing spine. It affects 2%-3% known. At the early stage of idiopathic scoliosis (IS), the signs hy the primarily school-based screening for scoliosis is so ross-sectional analysis of 6850 respondents. Participants were etropolitan area of Poland. The suspicion of IS was based on rmity of the spine using scoliometer. (3) Results: Respondents of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented 5º ATR showed that in the group of participants who had ATR ee values was recorded at the second and third measurement ectively). Analyzing the differences between the two groups of ically significant differences were recorded between 9 and 11 TR > 3º at all measuring levels are significantly slimmer than s: Age; sex, and risk of developing angle of trunk rotation are oracic (level 2) and thoraco-lumbar (level 3) level of measuring differentiating in the diagnosis of scoliosis. Girls with a lower k rotation), which can present mild scoliosis and those with a e lower body mass than girls within the norm. e of trunk rotation; optimal age screening; prevalence; school ost common pediatric musculoskeletal disorder that causes a ine [1]. It refers to about 2-3% of the adolescent population [2]. wn, researchers have focused on genetic factors, metabolic and metry with mechanical and connective tissue abnormalities. A b angle of 10º or more. As is generally known, IS progression than boys, especially during puberty [3]. The optimal age for e. The Scoliosis Research Society has recommended screening screening boys at the age 13 or 14 years [4]. Moreover, in recent and the American Academy of Orthopedic Society of North my of Pediatrics have endorsed school scoliosis screening kyo suggest that school screening for scoliosis is effective for value. In addition, a high percentage of participants with a five-degree value of ATR was also noted on the third measuring level-31.1%.
Our findings indicate trunk asymmetry correlates well with age, gender, and body mass. We found strong correlations of ATR value with age and sex. Over the analyzed material, more girls had a 5

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that ca three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent populat Although its etiology is largely unknown, researchers have focused on genetic factors, metabo hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormal common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS prog appears more frequently among girls than boys, especially during puberty [3]. The optimal scoliosis screening is still under debate. The Scoliosis Research Society has recommended scr girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in years, the Scoliosis Research Society and the American Academy of Orthopedic Society of America, and the American Academy of Pediatrics have endorsed school scoliosis scr programs [5,6]. Researchers from Tokyo suggest that school screening for scoliosis is effect ATR value than boys.
The optimal age screening for scoliosis is still under debate. Characterizing the relationship between different groups of age, we found a significant effect in the group of girls. In girls, the main thoracic and thoraco-lumbar level of measurement showed the significant effect of difference at age 11. Changes at the level of proximal thoracic presented statistically significant differences at the age of 13. Research results indicated the most significant level of measurement. Our findings suggest that girls should be screened for IS on the main thoracic and thoraco-lumbar section at the age of 11. The U.S. Preventive Services Task Force concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for adolescent idiopathic scoliosis in children and adolescent aged 10 to 18 years [23]. Trunk distortion of scoliosis involves other structures than the spine. Some researchers have suggested that the Cobb angle purely attains to the spinal deformity, while the ATR reflects a truncal and spinal deformity together [24].
Some studies conducted overseas have reported that low weight contributes strongly to the occurrence of scoliosis [25]. Unequal body mass in the girls group, an ATR of 0-3

Introduction
Idiopathic scoliosis (IS) is the most common pediatric musculoskeletal disorder that causes a three-dimensional deformity of the spine [1]. It refers to about 2-3% of the adolescent population [2]. Although its etiology is largely unknown, researchers have focused on genetic factors, metabolic and hormonal disorders, and growth asymmetry with mechanical and connective tissue abnormalities. A common diagnostic criterion is a Cobb angle of 10º or more. As is generally known, IS progression appears more frequently among girls than boys, especially during puberty [3]. The optimal age for scoliosis screening is still under debate. The Scoliosis Research Society has recommended screening girls at the age of 11 and 13 years and screening boys at the age 13 or 14 years [4]. Moreover, in recent , body mass was lower than in a group with ATR 0-3 scoliosis is a deformity of the growing spine. It affects 2%-3% known. At the early stage of idiopathic scoliosis (IS), the signs hy the primarily school-based screening for scoliosis is so ross-sectional analysis of 6850 respondents. Participants were etropolitan area of Poland. The suspicion of IS was based on mity of the spine using scoliometer. (3) Results: Respondents of trunk rotation (ATR) = 0 º -3º and ATR > 3º. Presented 5º ATR showed that in the group of participants who had ATR ee values was recorded at the second and third measurement ectively). Analyzing the differences between the two groups of ically significant differences were recorded between 9 and 11 TR > 3º at all measuring levels are significantly slimmer than s: Age; sex, and risk of developing angle of trunk rotation are racic (level 2) and thoraco-lumbar (level 3) level of measuring differentiating in the diagnosis of scoliosis. Girls with a lower k rotation), which can present mild scoliosis and those with a e lower body mass than girls within the norm. e of trunk rotation; optimal age screening; prevalence; school ost common pediatric musculoskeletal disorder that causes a ine [1]. It refers to about 2-3% of the adolescent population [2]. wn, researchers have focused on genetic factors, metabolic and metry with mechanical and connective tissue abnormalities. A b angle of 10º or more. As is generally known, IS progression than boys, especially during puberty [3]. The optimal age for e. The Scoliosis Research Society has recommended screening , which means that girls who are slimmer are predisposed to asymmetry of trunk rotation during the developmental stage. Cheung at al. (2003) in their research present that lower BMI means lower muscle mass which increases the risk of scoliosis [26]. Kyoungkyu at al. (2018) indicated that school students aged 10 to 14 years old in underweight and severely underweight groups had significantly higher risks of developing scoliosis, with risk levels that were 1.43 times and 1.45 higher, respectively [27]. As such, maintaining an appropriate weight level is very important for reducing the risk of scoliosis.

Strengths and Limitations
This research has some limitations. Respondents of this study were elementary school students applied to five age groups. Therefore, data cannot be extrapolated to other age ranges. Furthermore, there is still no consensus about the age at which school scoliosis screening should be started. The above research attempts to assess that age. In addition, it presents the level of the spine and which examination for IS detection cannot be missed.

Conclusions
Age, sex, and the risk of developing angle of trunk rotation are very closely associated. The main thoracic (level 2) and thoraco-lumbar (level 3) level of measuring the spine appears to be the most differentiating in the diagnosis of scoliosis. Therefore, in practice, researchers should focus mainly on