In this study, according to the analysis of the practice of washing hands before lunch according to gender, male students showed significantly higher practice rates than did female students. This finding is inconsistent with previous research results, with the reported gender-based hand washing practice rate in three South Pacific island countries being significantly higher for girls than boys . These results were also found in the Health Behavior in School-aged Children (HBSC) study and other prior studies conducted in Europe [13, 14]. These results can be explained in part by the implementation of health education programs for women and adolescents classified as underprivileged in communities in the countries of concern, but additional studies on the association between gender and personal hygiene are expected to be needed in the future, considering the national health policies. In addition, this study showed that the rate of hand washing was lower among high school students than among middle school students, and a prior study showed that as the students’ grade in high school increased, the number of students who said they did not wash their hands before lunch at school significantly increased. As a result, more careful monitoring and ongoing research on demographic and sociological factors affecting the practice of personal hygiene in schools are required . Good hand hygiene can prevent the occurrence of various diseases. In a randomized controlled study that evaluated the effects of hand washing using soap on acute respiratory tract infection, agro-vacuum and diarrhea prevention, the incidence of pneumonia in the hand washing group was 50% lower than that of the control group, 34% lower than that of the hand washing intervention group; moreover, hand washing with soap led to a 53% lower incidence of diarrhea . It has also been reported that handwashing serves to reduce the spread of infectious diseases such as influenza, parasites, trachoma, neonatal infections, HIV-related infections and enteritis [16–20]. Therefore, studies on how to habituate hand washing, which is most effective in reducing disease burden, during adolescence need to be conducted.
Insufficient oral hygiene-related behaviors in adolescence, such as an insufficient frequency of tooth brushing, increase the incidence of dental caries and, as a result, adversely affect not only the quality of life of adolescents but also the health of adults [21.22]. The practice of tooth brushing after lunch was analyzed in this study, and 69.2% of female students and 52.5% of male students were found to perform this behavior, and the difference between groups was statistically significant. Similar results were found in previous studies. In a study on the tooth brushing practice of 231 Korean middle and high school students that was conducted using the 2017 Korean National Health and Nutrition Survey data, male students brushed their teeth 2.43 times per day and female students brushed them 2.64 times per day . In addition, the rate of high school students who brushed their teeth after lunch was significantly higher than that of middle school students who brushed their teeth after lunch, and significant differences were identified across grade levels, which is consistent with the results in previous studies . Behaviors related to oral health in adolescence can easily become habits, and it is a very important period in which behavioral changes in oral health are possible because it is the transition period from childhood to adulthood. Therefore, it is considered necessary to develop a systematic oral health education program along with a multifaceted analysis of factors affecting oral health behaviors in adolescence.
The results of this study showed that adolescents who brush their teeth after lunch are significantly more likely to practice hand washing before lunch at school than are those who do not brush their teeth after lunch, and an association between oral hygiene and personal hygiene was confirmed. These results are consistent with those in previous studies, and 50.1% of students who brushed their teeth more than once a day always washed their hands after visiting the restroom, indicating that tooth brushing is closely related to personal hygiene habits . In addition, in a previous study conducted in middle school students from 15 Latin American countries, students who rarely brushed their teeth were 6.7 times more likely to wash their hands than were those who brushed their teeth more often, and the results of an analysis of these associations by gender also confirmed a significant association .
In this study, the positive association between tooth brushing and hand washing was found to be stronger in adolescents who participated in health education. These results are consistent with those in prior research, which have reported a 28.2% improvement in hand washing behavior and a 7.2% improvement in tooth brushing twice a day after hygiene education programs were implemented to improve knowledge and attitudes about hand washing and tooth brushing . These results suggest that health promotion programs are needed to improve the hygiene-related behaviors of adolescents. The education, knowledge, and attitude of adolescent students regarding health hygiene are thought to have a large impact on hygiene practice as well as on the students’ family and community. However, even if a school implements a health education program for personal hygiene management, it is difficult for students to perform personal hygiene management if the environment for tooth brushing and hand washing is poor; thus, the environment should be maintained, and a systematic health education program suitable for students should be developed and implemented.
Schools provide an important environment for the promotion of health at the most influential stage of individuals’ lives, during which individuals should develop sustainable health behaviors and maintain them throughout their entire lives . Therefore, the development and implementation of comprehensive and systematic school-based oral health promotion programs is necessary. Based on these findings, it is believed that comprehensive and systematic health policies are needed to improve youth hygiene and health.