Factors Related to Gender Differences in Toothbrushin g Among Lithuanian Middle-Aged University Employees

to them and poor oral health as injurious to general health. Of all respondents, 44% indicated that “Lack of time is the main reason for incomplete oral self-care” (61% of men and 40% of women, P<0.001). Logistic regression models showed that the strongest factor affecting toothbrushing frequency was the importance of good dental health to them (OR, 1.6; 95% CI, 1.1–2.4; P=0.02) among women and statement that “Poor oral health can be injurious to general health” (OR, 2.6; 95% CI, 1.2–5.5; P=0.01) and checkup-based habitual dental attendance (OR, 2.4; 95% CI, 1.0–5.9; P=0.06) among men. Conclusions. Due to different determinants affecting toothbrushing frequency among men and women, different oral health motivation programs by gender should be developed.


Introduction
Among the goals set by the World Health Organization for 2020, there are objectives to develop accessible cost-effective oral health systems for the prevention and control of oral diseases and to develop oral health programs that will empower people to control determinants of their oral health (1).
An increased knowledge about the development and management of dental diseases emphasizes the important role of oral health behavior in preventing or arresting caries and periodontal diseases (2)(3)(4)(5). Getting individuals to brush their teeth, together with regular visits to dental professional for reinforcement, seems to be the core pattern for the prevention of dental diseases (2,5).
Toothbrushing is one of the most effective, inexpensive, and easy methods of dental plaque removal (6). Brushing teeth twice a day and fl ossing on a daily basis are current recommendations in many countries.
Nationwide surveys show clear gender differences in the percentages of adults toothbrushing their teeth twice a day by country: 74% in the United Kingdom (83% of women and 64% of men) (7), 68% in Denmark (77% of women and 59% of men) (8), and 61% in Finland (76% of women, 45% of men) (9). These fi gures dramatically differ from those of the Lithuanian survey where only 39% of adults (50% of women, 23% of men) reported brushing their teeth more than once a day (10). The rates in Lithuania are more similar to those in the neighboring Baltic countries: 45% of adults in Estonia (57% of women, 30% of men) (11) and 43% of adults in Latvia (53% of women, 31% of men) (12) reported brushing their teeth more than once a day.
Scarcity of data to understand differences in oral self-care by gender encourages attempts to identify and evaluate the determinants of this phenomenon for effective oral health promotion.
The aim of this study was to evaluate the factors related to gender differences in toothbrushing among Lithuanian middle-aged university employees.

Material and Methods
The Kaunas Regional Ethics Committee for Biomedical Research (Lithuania) granted its permission to conduct the present study.
A questionnaire survey was anonymously conducted among university employees from March to June 2005 (13). One university from every of the 4 university cities in Lithuania was invited to participate based on having no medical teaching profi le. In every university, all employees aged 35 to 44 years (n=862; 629 women and 233 men) received an envelope with the questionnaire together with an invitation letter explaining the study design and encouraging them to respond. They were asked to complete the questionnaire and return it anonymously to an indicated address (offi ce/offi cer at the university) within two weeks. At returning the completed questionnaire, every respondent received a reward, a tube of toothpaste. The response rate was 64% (n=553).
The self-administered questionnaire inquired about oral hygiene habits, self-assessed dental health and appearance, habitual dental attendance, and dental health knowledge and attitudes.
The question "How often do you normally brush your teeth?" offered fi ve answering alternatives: more than once a day, once a day, almost daily, occasionally, and never. For the analyses, these alternatives were dichotomized as follows: more than once a day and less than that. Two respondents gave no information on their toothbrushing and were excluded from the present study.
Answering the question "How often do you use the following tools for interdental cleaning?" the answering alternatives were the same as for toothbrushing for each of the following three tools used for interdental cleaning: a toothpick, a dental fl oss, and an interdental brush. The missing answers were considered as never using the tool in question. For the analyses, the answers regarding every tool were dichotomized as follows: using it on a daily basis or not.
The questions "How would you assess your dental health?" and "How would you assess your dental appearance?" offered fi ve answering alternatives: very good, good, poor, very poor, and no opinion, later dichotomized as good and poor. The answer "no opinion," reported by 1% of the respondents in both questions, was excluded from the analyses.
The self-reported number of lost teeth was inquired with six alternatives, later categorized as three: none, one to two teeth, and three and more teeth lost.
The question "How do you normally visit a den-tist?" indicated the respondent's habitual dental attendance being for the reason of checkup or in case of trouble only. Dental health attitudes were described by the respondents' opinion on the following statements: "Good dental health is important to me," "Good dental appearance is important to me," and "Lack of time is the main reason for incomplete oral self-care," with every statement having fi ve answering options from "entirely agree" to "entirely disagree." The same options were offered while assessing respondents' knowledge of dental health with the statement "Poor oral health can be injurious to general health." The respondents' age, gender, marital status, education, and income served as background information. The respondents' age was evaluated by the question "When were you born?" with the answer required as the year of birth. Those born from 1960 to 1970 were defi ned as 35-44 year olds. For reporting marital status, four options were given: married or living together, single, divorced, and widowed; these were later dichotomized as cohabiting and single. The level of education was reported as follows: lower than secondary school, secondary school, vocational school, and university education, later dichotomized as university education and lower. The question "What was your household income in litas per person a month during the past six months?" offered the following 4 options: less than 300 litas, 300-500 litas, 501-1000 litas, and more than 1000 litas, later categorized as below average (up to 500 litas), average (501-1000 litas), and above average (more than 1000 litas).
Statistical Analysis. Data were analyzed using the statistical package SPSS (version 12.0). Descriptive statistics included percentages. Their differences between the groups were analyzed with the chi-square test based on the corresponding frequencies. Multivariable analyses were performed by logistic regression models to evaluate the strength of the factors related to reporting toothbrushing more than once a day. The models simultaneously controlled for all other factors included. Goodness of fi t was assessed by means of the Hosmer-Lemeshow test. Based on the estimates, produced by the models, odds ratios (OR) and their 95% confi dence intervals (CI) were calculated. A P value of less than 0.05 denoted statistical signifi cance.

Results
A total of 553 subjects (64%) responded; all were dentate. Their mean age was 40.11 years (SD, 3.19); the mean age of women and men was 40.10 (SD, 3.15) and 40.15 (SD, 3.36), respectively. There were 79% of women; 72% were married or cohabiting (70% of women and 77% of men, P=0.150), 82% had university education (83% of women and 78% of men, P=0.238), and 39% reported a medium household income (40% of women and 34% of men), with 38% being below (40% of women and 32% of men) and 23% above that (20% of women and 34% of men) (P=0.003). Of all the respondents, 68% reported brushing their teeth more than once a day. This habit was more frequent among women than men (73% vs. 49%, P<0.001). Interdental cleaning on a daily basis was most frequently reported as cleaning using a toothpick (38%), followed by a dental fl oss (26%) and an interdental brush (19%), a dental fl oss being indicated more frequently by women than men. Of the respondents, 55% reported using interdental cleaning tools on a daily basis, and 3% of the respondents reported never using any of such tools.
The majority assessed their dental appearance (72%) and their dental health (73%) as very good or good with no difference by gender.
Of all the respondents, 21% reported no teeth lost, 39% had lost one-to-two teeth, and 40% more than one or two.
A checkup as the reason for habitual dental attendance was reported by 51% of the respondents (54% of women vs. 41% of men, P=0.012).
Almost all stated that good dental health (98%) and appearance (97%) was important to them and that poor oral health could be injurious to general health (97%). A greater percentage of women than men entirely agreed with the statement that dental appearance was important to them (68% vs. 50%, P<0.001). Nearly half of the respondents (44%) agreed with the statement "Lack of time is the main reason for incomplete oral self-care" (61% of men and 40% of women, P<0.001).
Gender differences in toothbrushing frequency were statistically signifi cant within most of the subgroups according to the respondents' characteristics (Tables 1 and 2). Bivariate analyses separately for women and men revealed that toothbrushing more than once a day among women was more prevalent among those with university education (75% vs. 60%; P=0.009) ( Table 1) and among those entirely agreeing with the importance of good dental health to them (77% vs. 63%; P=0.004) ( Table 2). Among men, good self-assessed dental appearance, checkup-based dental attendance, and disagreement with the statement "Lack of time is the main reason for incomplete oral self-care" were signifi cant determinants of toothbrushing more than once a day ( Table 2).
Similar logistic regression models were fi tted to the data separately for women and men in order to show the strength of the factors related to reporting toothbrushing more than once a day. For women (Table 3), the strongest factor was the importance of good dental health to them (OR, 1.6; 95% CI, 1.1-2.4; P=0.02). For men (Table 4), the strongest factors were agreeing with the statement "Poor oral health can be injurious to general health" (OR, 2.6; 95% CI, 1.2-5.5; P=0.01), reporting checkupbased dental attendance (OR, 2.4; 95% CI, 1.0-5.9; P=0.06), and disagreeing with the statement "Lack of time is main reason for incomplete oral self-care" (OR, 1.5; 95% CI, 1.1-2.0; P=0.02).

Discussion
The present study revealed a clear gender differ-  ence in factors related to toothbrushing frequency. However, it was associated with different attitudes toward dental health in both genders. The results of the present study showed that women and men had different beliefs about dental health that may infl uence the toothbrushing frequency. Toothbrushing frequency among women was associated with strong agreement with the statement about importance of dental health to them. However, among men, the reported checkup-based dental attendance as well as disagreement with the statement "Lack of time is the main reason for incomplete oral self-care" correlated with their toothbrushing frequency. The results partly support an earlier notion of poor correlation of knowledge and health-enhancing behavior (14). It therefore appears from the results that knowledge of dental health may infl uence toothbrushing frequency only for men. Even though the vast majority of all respondents stated that poor oral health could be injurious to general health, this seemed to be associated with toothbrushing frequency among men only. Despite the fact that a signifi cantly greater percentage of women than men entirely agreed that dental appearance was important to them, this belief was not related to toothbrushing more than once a day among women.
No common factors were found to be associated with toothbrushing frequency for both genders. The reported higher frequency of toothbrushing was observed among women with university education as compared with the lower levels of education, while among men, it was related to better self-assessment of dental appearance, fewer reported teeth lost, and more frequently indicated checkup-based reason for the habitual dental attendance.
It has been previously shown that women exhibit better oral self-care than men do. However, there are almost no studies analyzing the factors associated with preventive oral self-care by gender. In Japan, a study among adults has demonstrated that the factors affecting preventive oral self-care behavior differ by gender and that health behavior is more elusive in men than women (15). These results emphasize the need for further research to understand the sources of gender differences in dental health behavior.
Analysis of differences in health behavior of women and men showed that gender differences in preventive oral self-care were observed already among adolescents -girls demonstrated better knowledge of dental health, sound teeth were more important to them, and they practiced dental hygiene habits more frequently (26). Apparently, these differences persist into adulthood, possibly because of parents' oral self-care refl ection on their children's corresponding behavior (27). Thus, gender differences related to oral health could be transmitted between generations. The signifi cance of mothers' and fa- thers' roles as a model for behavior of their children is an important issue for further studies.
The limitation of the present study is a restricted sample of middle-aged, urban, female-dominated target group with a high level of education and most commonly with an average income or income above average in Lithuania. Among the respondents, the majority (79%) were women, closely corresponding to gender distribution in the target population of middle-aged university employees (73% of women vs. 27% of men). Taking into consideration the above-mentioned aspects of the study sample, this group of individuals is likely to represent most favorable preventive dental health behavior in the country. Good oral hygiene is generally considered as socially acceptable behavior, and consequently, the individuals with higher education may express the wish to demonstrate more of it than it is in reality. Thus, some overreporting of preventive oral hygiene habits as well as dental health attitudes and knowledge might have happened (28). Still, this group with higher socioeconomic status reported similar or lower rates of oral self-care than those found in national studies in Western European countries. This situation calls for more emphasis on implementing oral self-care promotion programs within Lithuanian adult population, for men in particular.

Conclusions
Due to the different determinants affecting toothbrushing frequency among men and women, different, gender-focused health education and motivation programs are advisable to strengthen preventive oral self-care among adults. A special emphasis should be placed on men representing high-risk group in this context. More studies involving high-risk individuals are needed to identify behavior-related factors in order to optimize oral health care.

Statement of Conflict of Interest
The authors state no confl ict of interest.