Change in Growth Status and Obesity Rates among Saudi Children and Adolescents Is Partially Attributed to Discrepancies in Definitions Used: A Review of Anthropometric Measurements

Anthropometric measurements are the first step in determining the health status in children and adolescents. Clinicians require standardized protocols for proper assessment and interpretation. Therefore, this study aims to review the literature of international and Saudi national guidelines and studies previously conducted in Saudi children and adolescents to provide recommendations to establish Saudi guidelines in line with the Saudi 2030 Vision. Systematic search was conducted in several databases: Medline, PubMed, Saudi Digital Library and Google Scholar from January 1990 to January 2021. Further, 167 studies measured anthropometrics in Saudi children/adolescents; 33 of these studies contributed to the establishment/adjustment of Saudi growth charts or specific cutoffs or studied the trend of growth in representative samples or adjusted the international curves to be used in Saudis. This review warrants updating growth charts and establishing the standard cutoffs of Saudi adolescent anthropometrics to avoid over/underreporting. This review provides insights and recommendations regarding the resources that can be used to establish national guidelines in anthropometric measurements for Saudi children/adolescents. This review will help policymakers and the Ministry of Health to establish standardized protocols to be used in Saudi Arabia for anthropometric measurements that may assist in detecting malnutrition.


Introduction
Saudi Arabia launched the 2030 vision in 2016, which outlined the future goals of the country and their objectives. One of the vision's themes is having a vibrant society by improving healthcare services and promoting a healthy lifestyle [1]. In addition, Saudi Arabia aims to increase life expectancy at birth by 6 years, from 74 years to 80 years, an average gain of 0.43 years per annum [1]. Determinants of life expectancy trends are dependent on the "cardiovascular revolution", which combines smoking prevalence, obesity, lifestyle and related policies. These behaviour-related problems occur in Saudi Arabia and should be addressed in order to increase life expectancy at birth [2]. Therefore, reviewing the trends of growth, obesity, lifestyle changes and providing standardized growth charts and recommendations in establishing Saudi guidelines of anthropometric measurements is the first step that may help in increasing life expectancy.
Anthropometry is from Ancient Greekaνθρωπoς (ánthrōpos) 'human', and µέτρoν (métron) 'measure' [3]. Anthropometrics are defined as "the study of human body measurements" [4]. Anthropometric measurements assess body composition by measuring muscles, bone and adipose tissue mass quantitively. The main anthropometric measurements that represent diagnostic criteria for obesity are height, weight, body mass index (BMI), skinfold thickness and body circumferences (waist, hip and limb) [5]. Regarding children, head circumference (HC), mid-upper arm circumference (MUAC) and growth charts [6] are part of the nutrition assessment and help in malnutrition diagnosis and predict growth [7]. Anthropometries are widely used in field and clinical situations due to their simplicity, portability, inexpensiveness and safety. Anthropometric measurements are also commonly used in large population studies due to their convenience [8]. Thus, anthropometric measurements are significant in preventing health risks, determining health status and improving individuals' quality of life, which are all part of the Saudi Vision 2030.
High body mass index (BMI) is a diagnostic criterion for overweight and obesity [5] and is one of the main reasons for increasing Saudi Arabia's morbidity and disease burden [9]. Overweight and obesity negatively affect people's socio-economic status due to their association with lower education attainment. Other economic consequences are the increase in health expenditure from treatments of overweight and obesity and their related comorbidities and their impact on productivity and workforce participation [10]. Consequently, anthropometric measurements and their cutoffs that are used to identify overweight and obesity are the first steps in determining their prevalence.
The concerning increase in the global prevalence of obesity and its related morbidity and mortality marked the significance of the assessment of body size, shape and composition for health. Research efforts have progressed to understand obesity, and, despite these efforts, the global burden of obesity is increasing. This mandates the need for standard guidelines for anthropometric measurements to estimate the prevalence of overweight and obesity and predict healthcare costs and disease mortality. To ensure these measurements are taken precisely, clinicians must have access to national valid and reliable cutoff measures.
To our knowledge, there are no standard national guidelines established for the Saudi population to evaluate anthropometric measurements. The issue is particularly important among children and adolescents, where there are several charts and definitions used to monitor children's growth. Most recent studies on children in Saudi Arabia from 2010 to 2019 defined obesity and overweight using the US Centers for Disease Control (CDC) or the recent WHO criteria; others used the International Obesity Task Force criteria or the Saudi BMI percentile [11]. These differences in the standards used to define growth status in children (whether obesity or underweight) make it challenging to compare studies at the national level and, accordingly, to make accurate conclusions. For example, the prevalence of overweight/obesity has been reported to be lower when using the International Obesity Task Force (IOTF) definition compared to the use of definitions from the CDC and the WHO [12]. Overall, there is inconsistency in measuring and reporting of physical measurements among Saudi children and adolescents, which can be largely attributed to the lack of national guidelines.
Therefore, the aim of this review is to (1) review the literature on international and Saudi national guidelines of anthropometric measurements and studies previously conducted in Saudi Arabia. (2) The review will provide insights and recommendations regarding the resources that can be used to establish national guidelines and cutoffs in anthropometric measurements for Saudi children/adolescents that are in line with the Saudi vision 2030.

Materials and Methods
Several electronic databases were searched: Medline, PubMed, Saudi Digital Library and Google Scholar from January 1990 to January 2021 [13]. The search included the use of Medical Subject Headings (MeSH) and other key words (Table S1). Hand searches of reference lists of retrieved articles were undertaken and studies prior to 1990 were included in Table S2. After screening titles and abstracts from the searched databases, 724 full articles were screened for eligibility. A total of 167 Saudi children/adolescent studies measured anthropometrics ( Figure 1). All studies in English language were included, even PhD theses and abstracts that provided sufficient information.

The US Centers for Disease Control (CDC)
The US Centers for Disease Control (CDC) also provide growth standards for children, body measurements guidelines and interactive tools. These were based mainly on data from the National Health and Nutrition Examinations Survey (NHANES) with supplemental surveys and were collected solely from the American population [20,21]. The CDC growth reference has been widely used in other populations, including Saudi Arabian children. After the release of the 2005 WHO growth charts, the CDC adopted the WHO growth curves for children under the age of 2 years. For children 2-18 years, the CDC has its own charts. Several improvements have been made on the 2000 CDC growth charts throughout the years; however, the name "2000 CDC growth charts" remained the same [6].
Differences exist between the CDC and WHO growth charts depending on the age group, growth indicator and specific Z-score curve [22]. These differences were of importance during infancy, which led the CDC to adopt the WHO growth charts for those under the age of 2 years. Moreover, the WHO length/height-for-age standards have less variability compared to the CDC. Both the weight-for-length and weight-for-height charts indicated that children in the CDC (US studies) were generally heavier. This was reflected in the BMI for age, leading to major differences in the estimates of underweight, overweight and obesity; higher rates of obesity and lower rates of underweight are expected when the WHO BMI-for-age standard is used [22].

The International Obesity Task Force (IOTF) BMI Cutoffs
Other cutoffs that have been widely used in children are those established by the International Obesity Task Force (IOTF) ( Table 1). Centiles were constructed for children 2 to 18 years using data obtained between 1963 and 1993 from six countries: the UK, USA, The Netherlands, Brazil, Singapore and Hong Kong. No cutoffs are available for children under the age of two years. The IOTF standards provide only BMI cutoffs for overweight, obesity and underweight (thinness) by linking the data to adult's BMI cutoff points [23][24][25]. Standards for overweight [25] and underweight [24] were published in 2000 and 2007, respectively. Some improvements were completed in 2012 using the same data to allow for calculating the SD scores in addition to the centiles [23]; the differences between the original and the updated curves have minimal impact on BMI classifications [23,26].

International Diabetes Federation (IDF)
Central (abdominal) obesity is an indicator of adverse health outcomes and is commonly estimated by measuring the waist circumference. The IDF also provides waist circumference percentiles for children and adolescents starting at age 6 years, but the IDF does not recommend the diagnosis of metabolic syndrome for children under 10 years. Cutoffs used were categorized based on age groups 6 to <10, 10 to <16 and ≥16 years [27]. The IDF waist circumference cutoff for adolescents has been reported to be applicable to Spanish adolescents in predicting metabolic syndrome [28].

The Saudi National Guidelines
Growth reference for length/stature, weight and head circumference were published in 2007 based on a representative sample of children and adolescents from the 13 administrative regions in Saudi Arabia [29]. The sample included 35,279 eligible healthy children and adolescents from birth to 19 years of age. Charts for BMI were developed later in 2009 that appear to be completed using the same sample of children included in El-Mouzan et al. (2007) [29]; however, in the methodology, they did not refer to the original article that collected the sample [30]. For children, the Saudi BMI-for-age charts provided by the Ministry of Health (MOH) do not have percentiles below the 50th percentile, although the original article provides them [29]. The booklet provides them for <60 months: https://www.moh.gov.sa/en/Ministry/MediaCenter/Publications/Pages/ Child-Health-Passport.pdf (accessed on 1 January 2022).
The 2005 Saudi growth charts are the ones endorsed by the Saudi MOH [31,32]. However, recent modifications to the charts of children 0-60 months of age have not been adopted yet [33,34]; one re-analysed the data to reconstruct the percentiles for weight, length/height, head circumference and body mass index for age and weight for length/height [33], whereas the second one created Z-scores reference values for the same age group [34]. There have been Saudi growth standards established by the MOH for children under the age of 5 years published in 2000 [35] and 2004 [36], but they covered five regions only out of the thirteen regions and are no longer used; the two studies appear to be the same, with slight differences in authors list and the journal.
Comparisons of the WHO to the current Saudi growth charts showed a higher rate of stunting and wasting in Saudi children when the WHO charts were used [37]. The authors concluded that the WHO charts were constructed in privileged populations and are not suitable for use in some populations. Ideally, optimum growth should be based on well-nourished children and not unprivileged or undernourished children. Comparisons of the CDC to the current Saudi growth charts showed an underestimation of overweight and obesity, as well as an overestimation of undernutrition, stunting and wasting when the CDC charts were used [38,39]. The study that constructed the charts for BMI for age in 2009 aligned the charts to the CDC and WHO charts, but it is not clear how the prevalence of underweight/overweight were impacted [38].

Non-Traditional Measurements
There are body measurements that have been correlated with children's growth status such as kidney length, penile size, body surface area and placental weight. Some studies explored these measurements in Saudi children including kidney length [40], penile size [41], body surface area [42], placental weight [43] hand grip strength [44]. These studies were not included in Table 2 and are summarized here. Mohtasib et al. reported that, in 950 Saudi children, left kidneys were longer than right kidneys, and consistent difference in kidney length by sex was observed. Both kidneys were longer in males than females. In addition, from several anthropometrics, height had the most significant correlation with kidney length [40]. Furthermore, AlHerbish established standards for penile size for normal full-term Saudi newborns. The mean penile length of 3.55 cm in this study was similar to previously reported international data [41]. The body surface area is of great interest for clinicians because it is widely used for determining drug dosages and for calculating the needs of patients for parenteral fluids and electrolytes [45]. From Saudi newborns in Abha, two simplified equations based on weight and height were created to calculate body surface area in Saudi newborns [42] and in adults [46]. Table 2 shows a total of 167 studies assessing anthropometrics in Saudi children and adolescents. Table 2 reports the cutoffs used in the studies and whether the studies mentioned how the anthropometrics were measured. Studies assessing children's growth using anthropometrics started since 1977 [47] (Table S2) and included the capital city Riyadh and other cities, whereas other studies assessed children's anthropometrics in villages, including Wadi Turaba [48], Khulais [49] and other villages [50]. Alfrayh and colleagues were the first to publish data from Riyadh and constructed physical growth standards [51].                 Table 2 contributed to the establishment/adjustment of Saudi growth charts for children/adolescents or specific cutoffs or studied the trend of growth in representative samples or adjusted the international curves to be used in Saudis. Figure 2 shows the use of growth chart standards in Saudi children and adolescents. Figure 2 did not include studies that were used to establish growth standards at the national or regional levels. The majority of the studies used WHO (23%), CDC (17%), NCHS (17%) and IOTF (15%) cutoffs, although Saudi growth charts were published since 2005 [29]. Saudi growth charts are available on the website of the Saudi Ministry of Health (see Section 3.5); however, few studies used the Saudi growth chart cutoffs [34,40,97,129,132,196]. Only 4% of the studies used the Saudi growth charts (Figure 2). This is consistent with Mosli R. 2018 [197], who reported that 70% of pediatricians and dietitians in Saudi Arabi typically used CDC or WHO growth charts. However, the study included a small sample size (n = 105). Another study reported the low use of growth charts in the Middle East [198]. In regard to using the Saudi growth charts for Saudi adolescents, a study found that hospitals in Jeddah used international standards for anthropometrics (60%) compared to national standards of anthropometrics (10%). The study highlights the importance of standardizing the practice of anthropometric assessment among the Saudi adolescent group [199]. Larger representative studies are needed and identification of the reasons of not using the Saudi growth charts are crucial. Overall, most of the studies in children/adolescents were conducted in Riyadh and more studies are needed in other regions of Saudi Arabia. Few studies included a representative sample of the Saudi population from all regions ( Table 2). A total of 33 studies highlighted in Table 2 contributed to the establishment/adjustment of Saudi growth charts for children/adolescents or specific cutoffs or studied the trend of growth in representative samples or adjusted the international curves to be used in Saudis. Figure 2 shows the use of growth chart standards in Saudi children and adolescents. Figure 2 did not include studies that were used to establish growth standards at the national or regional levels. The majority of the studies used WHO (23%), CDC (17%), NCHS (17%) and IOTF (15%) cutoffs, although Saudi growth charts were published since 2005 [29]. Saudi growth charts are available on the website of the Saudi Ministry of Health (see Section 3.5); however, few studies used the Saudi growth chart cutoffs [34,40,97,129,132,196]. Only 4% of the studies used the Saudi growth charts (Figure 2). This is consistent with Mosli R. 2018 [197], who reported that 70% of pediatricians and dietitians in Saudi Arabi typically used CDC or WHO growth charts. However, the study included a small sample size (n = 105). Another study reported the low use of growth charts in the Middle East [198]. In regard to using the Saudi growth charts for Saudi adolescents, a study found that hospitals in Jeddah used international standards for anthropometrics (60%) compared to national standards of anthropometrics (10%). The study highlights the importance of standardizing the practice of anthropometric assessment among the Saudi adolescent group [199]. Larger representative studies are needed and identification of the reasons of not using the Saudi growth charts are crucial. Overall, most of the studies in children/adolescents were conducted in Riyadh and more studies are needed in other regions of Saudi Arabia. Few studies included a representative sample of the Saudi population from all regions ( Table 2). Discrepancies in classification of weight status have been observed in many studies when using different growth charts. A study in Spain reported that rates of overweight and obesity were doubled when plotted against the WHO growth standards compared to a locally established reference [200], similar in Iranian children [201]. Two studies in representative samples of Saudi children compared the children's growth using the current Saudi growth charts, the WHO [37]and the CDC [38]. These studies found that the prevalence of undernutrition, stunting and wasting was increased in Saudi children when using the WHO standards or the 2000 CDC growth charts [37,38].

Assessment of Growth Status in Studies Targeting Saudi Children
We explored the standards used in assessing children's growth in Saudi Arabia across the years. Studies that were used to establish Saudi growth standards at the national or regional levels were excluded in this analysis. Figure 3 shows the breakdown of the used standards between 1980 and 2021 (A) and stratified into before 2008 and 2008 Discrepancies in classification of weight status have been observed in many studies when using different growth charts. A study in Spain reported that rates of overweight and obesity were doubled when plotted against the WHO growth standards compared to a locally established reference [200], similar in Iranian children [201]. Two studies in representative samples of Saudi children compared the children's growth using the current Saudi growth charts, the WHO [37] and the CDC [38]. These studies found that the prevalence of undernutrition, stunting and wasting was increased in Saudi children when using the WHO standards or the 2000 CDC growth charts [37,38].
We explored the standards used in assessing children's growth in Saudi Arabia across the years. Studies that were used to establish Saudi growth standards at the national or regional levels were excluded in this analysis. Figure 3 shows the breakdown of the used standards between 1980 and 2021 (A) and stratified into before 2008 and 2008 onwards (B). The year 2008 was selected as the current Saudi growth standards were endorsed by the Ministry of Health in 2007. In 2008 onwards, the WHO growth standards remained the main growth chart used (28%), followed by the 2000 CDC charts (21%); only 6% used the current Saudi growth charts. Before 2008, different versions of the National Center for Health Statistics charts were mainly used; almost no one used Saudi growth charts, although there were multiple published before the current Saudi charts. Issues in reporting were observed, such as not citing the source, unclear cutoffs/definitions and based on other references that are not commonly used. These differences in criteria used to define children's growth create a challenge for many researchers and health officials as they cannot conclude whether the differences in overweight/obesity rates across regions and/or across the years are actual or are due to differences in the tools and definitions used. and/or across the years are actual or are due to differences in the tools and definitions used.

Recommendations for Establishing Saudi Guidelines of Anthropometric Measurements and Directions for Future Work in Line with the Saudi 2030 Vision
This review did not focus on preterm infants; however, recommendations were provided based on the available evidence. Preterm infants' growth should be monitored using postnatal growth standards specifically for preterm. These growth charts have been established using the INTERGROWTH-21st Project and can be used for the assessment of preterm infants until 64 weeks postmenstrual age [202]. These growth charts have been

Recommendations for Establishing Saudi Guidelines of Anthropometric Measurements and Directions for Future Work in Line with the Saudi 2030 Vision
This review did not focus on preterm infants; however, recommendations were provided based on the available evidence. Preterm infants' growth should be monitored using postnatal growth standards specifically for preterm. These growth charts have been established using the INTERGROWTH-21st Project and can be used for the assessment of preterm infants until 64 weeks postmenstrual age [202]. These growth charts have been published in The Lancet Global Health Journal in 2015 and are generalizable to other populations if individuals are healthy, well-nourished and free from environmental and socioeconomic constraints on growth ( Table 3).
The Saudi growth charts have several limitations, including absent percentiles, no guidelines for interpretation and outdated cutoffs, which makes it necessary for an update. The WHO recommends that new estimates should be completed for anthropometric indicators every three years so that countries can regularly update their progress towards the Sustainable Development Goals (SDG goals) [15]. The endorsed growth charts on the website of the Saudi Ministry of Health were published in 2005. The WHO growth charts may be the recognized standard, particularly for children under 5 years old, as they are based on a prospective study using a sample of healthy children from six different countries on five different continents (Brazil, Ghana, India, Norway, Oman and the United States) with varying ethnic groups living in an environment that did not constrain optimal growth. However, only one country out of the twenty-three Arabic countries was included (Oman) and may not be similar to Saudi Arabia [203]. In addition, several countries had created their own growth charts and compared them with the WHO growth charts and reported misclassifications, including Korea [204], Spain [200] and Iran [201]. The United States adopted the WHO growth charts only for those aged 2 years and younger but still recommends the CDC charts for children older than 2 years. The rigorous methods used when creating the WHO growth standards for children 0-5 years are recommended when updating the Saudi growth charts. To prevent false impressions of a good percentage of the population being in a healthy condition due to an increase in the normal weight curves, several points and methods need to be considered depending on the age group (Table S3).
A complete guide providing recommendations for data collection, analysis and reporting on anthropometric indicators in children under 5 years old was published in 2019 by the WHO and UNICEF [15]. The guide is available in four languages, including an Arabic version, which is convenient for Saudi Arabia. The guide provides recommendations on planning, sampling, questionnaire development, training, standardization, equipment, field work processing and reporting data ( Table 3). Several points need to be checked to assess the quality of anthropometric survey data to generate accurate child malnutrition status. These points are summarized in Section 3.1 in the WHO guidelines [15]. We recommend that, when updating the Saudi growth charts, they follow these guidelines to provide a clear understanding of the magnitude and distribution of malnutrition problems in the country and to design and monitor interventions to improve the nutritional status of the population concerned (Table S3). However, it is important to note that the data quality cutoffs provided by the WHO for children < 5 years old need to be revised, as stated by the WHO, for various reasons [15]. One of the reasons was that these cutoffs were developed using a "set of surveys not all of which were nationally representative and included several rapid nutrition surveys conducted in emergency situations, where the populations concerned were probably more homogeneous with respect to nutrition status and its determinants". Therefore, as a starting point, Saudi Arabia may develop a nationally representative survey using the accurate and rigorous guidelines provided by the WHO to ensure high-quality data that may help the WHO revise their data quality cutoffs.
After updating the Saudi growth charts, endorsing them to be used by clinicians and publishing them on the Saudi MOH website are required. More studies are needed to identify the reasons of not using the Saudi growth charts (discussed in Section 4.2) [200,201]. To ensure that the Saudi growth charts are used, hospitals and clinics should include them in their protocols and reporting growth status should be documented in hospital systems. These data may help researchers to study growth trends and compare growth between regions [35,93,170], low and high altitudes [81], public and private schools and study factors impacting anthropometrics that may help in increasing life expectancy. In addition, the availability of anthropometrics data may assist in meeting the goals of the Kingdom's Vision 2030 in the transformation towards a sustainable knowledge-based economy [1]. To use anthropometric data in research, it is recommended to conduct data cleaning of anthropometric data from electronic health records. A protocol has been proposed and applied in a large UK patient cohort [205]. A systematic review found several non-traditional anthropometrics that can be used to identify obesity in children [206]. These can be studied in the Saudi population and specific cutoffs developed to help in the prevention of childhood obesity. Overall, using the WHO/CDC or other growth charts results in over/underestimation of the prevalence of obesity, stunting, wasting and malnutrition [37,207]; thus, updating and using the Saudi growth charts are essential.
After updating the Saudi growth charts and endorsing them to be used by all healthcare settings, specific cutoffs should be developed for 6-18-year-old children since the Saudi growth charts are up to 5 years only. Saudi growth charts were created for ≥6 years children-19 in 1996/1998 [68,70], and growth charts for the ages 5-19 years are available on the Saudi MOH website [208] from the study [29]. In 2015, a nationally representative adolescent study identified high prevalence of sedentary behaviours, poor dietary habits and overweight and obesity [178], indicating the need to update the Saudi growth charts for adolescents. The WHO published a guideline on school health services, such as referral and management of overweight and obesity [209]. A collaboration between the Saudi MOH and Saudi Ministry of Education is essential to develop a protocol for annual screening of anthropometrics of all children enrolled in governmental and private schools to ensure growth and prevent obesity and its comorbidities. Children in Saudi Arabia start Year 1 by the age of 6-7 years and kindergarten is not compulsory; therefore, an established protocol to ensure annual screening is necessary to include all children regardless of starting school (Table 3).

Individuals with Health Conditions and Disabilities
A study showed that 718 newborns from 2000 to 2012 were registered with neural tube defects in King Faisal Specialist Hospital and Research Center. This was associated with not consuming folic acid preconception and in the first trimester [210]. Consequently, the creation of a national birth defect registry has been proposed to collect, analyse and report to policymakers [211]. These data may help in identifying their causes and conducting preventive measures. Currently, there are two national screening programs in Saudi Arabia: the premarital screening program and the national newborn screening program [212]. Both programs are mainly screening for genetic disorders in a manner either aiming to detect couples who are carriers or affected before their marriage or detecting affected newborns at early stages. The incidence of newborn errors in Saudi Arabia is one of the highest worldwide due to high rate of consanguineous marriages in Saudi Arabia. Compared to many countries, Saudi Arabia has only two screening programs and more screening programs are needed, such as the "newborn and infant physical examination" program conducted in the UK.
Researchers created Saudi growth charts for individuals with Down syndrome in 2003 [213]. However, these charts need to be updated and distributed to be used and endorsed by the Saudi Ministry of Health. No studies have been found to assess the utilization of the Saudi growth charts for Down syndrome. Furthermore, body surface areas have been mentioned in Section 4.1 as they are a major factor in the determination of the course of treatment and drug dosage. Two studies were conducted in the Saudi population that created simplified equations based on anthropometric measurements to calculate body surface area in newborns and adults [43,47]. However, the studies included small sample sizes and larger representative studies are needed to create these equations. A recent study provided several equations of body surface area based on weight, height, sex and age of patients that can be used when creating these equations for the Saudi population [214]. A systematic review suggested that muscle mass may be the new body surface area for chemotherapy dosing [215]. Table 3. Summary of recommendations for establishing Saudi guidelines of anthropometric measurements for children/adolescents and directions for future work in line with the Saudi 2030 Vision.

Recommendations-Children/Adolescents
Directions for Future Work 1. Use preterm infants' growth standards for preterm infants if preterm infants are well-nourished and free from environmental and socioeconomic constraints on growth until 64 weeks postmenstrual age [202] Develop a protocol to be used in all hospitals and to be endorsed by the Saudi MOH 2. Update the Saudi growth charts (SGC) using the WHO and the United Nations Children's Fund (UNICEF) guideline for children under 5 years old, Arabic version [15] (see Table S3) Use the WHO protocol for anthropometric measurement [15] to ensure standardization and provide a guideline for pediatricians, dietitians, general practitioners and family doctors on how to use the SGC and interpret them. Integrate SGC into electronic health records [216] Develop a protocol on anthropometric data documentation in hospital systems and to be reported to the Saudi MOH More studies on the assessment of growth status (growth charts used) of Saudi children and the reasons of why Saudi growth charts are not used by some clinicians are needed [200,201]

Recommendations-Children/Adolescents Directions for Future Work
3. Explore non-traditional anthropometrics to define obesity in Saudi children and develop specific cutoffs [206] Non-traditional anthropometrics, such as chest and wrist circumference, body mass abdominal index etc. [206] can be used in the case of limited equipment available and may help prevent childhood obesity by early detection 4. Update the SGC for children/adolescents ages 5-19 years [209] (see Table S3) Collaboration between Saudi MOH and Saudi Ministry of Education to develop a protocol for annual screening of anthropometrics in schools [209] Provide a guideline for paediatricians, dietitians, general practitioners and family doctors on how to measure anthropometrics to ensure standardization and how to use the Saudi growth charts and interpret them [199] More studies on the assessment of growth status (growth charts used) of Saudi adolescents and the reasons of why Saudi growth charts are not used are needed [199] Develop a protocol on anthropometric data documentation in hospital systems and to be reported to the Saudi MOH Recommendations for Individuals with Health Conditions and Disabilities Directions for Future Work 5. Update SGC for Down syndrome [213] Update, publish the Saudi cutoffs and endorse them to be used by the Saudi MOH 6. Create simplified equations to calculate body surface area in Saudi children and adults from large representative Saudi samples [43,47].
Equations to calculate body surface area are created from anthropometrics (e.g., weight, height). Body surface area is a major factor in the determination of the course of treatment and drug dosage and can be used by physicians in different medical conditions (e.g., transplantation, predict chances of survival in burn patients, nephrotic syndrome) [214] Provide a guideline for health practitioners on when and how to use body surface equations to ensure standardization and how to interpret the results. Generalize and endorse the use of body surface equations by the Saudi MOH 7. Create a national birth defect registry [211] The data from the registry will help in identifying the prevalence, trends, the causes of birth defects and conducting preventive measures.
Legend: MOH: Ministry of Health, SGC: Saudi growth charts, WHO: World Health Organization.

Conclusions
Anthropometric measurements are the first step in determining health status. In this review, we have summarized the evidence of anthropometric measurements used in Saudi children and adolescents. Saudi growth charts for children/adolescents are available; updating them and endorsing their utilization are essential to ensure standardization and help in determining health status. The Saudi growth charts are underused in research conducted on Saudi children and studies are needed to assess the reasons for not using them. This review provides recommendations for establishing Saudi guidelines of anthropometric measurements and directions for future work in line with the Saudi 2030 Vision. This review will help policymakers and the Saudi MOH to establish reports and national guidelines to be used in Saudi Arabia for anthropometric measurements and their valid cutoffs that may assist in detecting malnutrition and preventing it.
Supplementary Materials: The following supporting information can be downloaded at: https://www. mdpi.com/article/10.3390/healthcare11071010/s1, Table S1: Systematic search terms using MeSH for the literature review. Table S2: Saudi children/adolescent studies measuring anthropometrics before 1990. Table S3: Guidelines and recommendations for updating the Saudi growth charts and to assess the quality of anthropometric survey data based on the WHO recommendations. Informed Consent Statement: Informed consent was obtained from all subjects involved in the studies.

Data Availability Statement:
No new data were created or analysed in this study. Data sharing is not applicable to this article.