Hand hygiene is one of the most important measures available to prevent infectious diseases such as COVID-19, and it is recommended that individuals wash their hands periodically before and after meals, after using toilets, before preparing food at home, at schools, and in public places. The aim of this study was to investigate the relationship between oral hygiene and hand hygiene in Korean adolescents. Data from 57,303 adolescents who participated in the 2019 Korea Youth Risk Behavior web-based survey were analyzed to determine the relationship between oral hygiene and hand hygiene. A complex sample logistic regression analysis was performed to determine association between toothbrushing behavior and handwashing practices. According to the results of this study, adolescents who brushed their teeth after lunch were 1.48 times more likely to practice handwashing before lunch than were those who did not brush their teeth after lunch (p < 0.001). In addition, the odds ratios adjusted for gender, grade, school type, and residence were found to be 1.87 (p < 0.001). Moreover, these adjusted odds ratios were higher in students who received personal hygiene education (OR: 1.98, p < 0.001). Oral hygiene practices were found to be related to personal hygiene, as assessed by handwashing, in Korean adolescents. Additional studies are needed to develop ways of improving the hygiene and health of adolescents.

This study aimed to verify the relationship between handgrip strength and oral health using data from the Korea National Health and Nutrition Examination Survey, representing Korean adults. Data from the seventh survey (2016–2018) conducted by the Korea Centers for Disease Control and Prevention were utilized, and 10,607 final study participants were recruited according to the selection and exclusion criteria. A complex sample logistic regression analysis was performed to confirm the relationship between handgrip strength and dental caries according to the sex of the study participants. On analyzing the correlation in men, “C1 (DMFT: 11–32),” when compared to “C4 (DMFT: 0–3),” in Model 1 without adjustment for potential confounders, was 2.92 (95% confidence interval [CI]: 2.15–3.97) times more likely to be associated with lower handgrip strength, and a statistically significant result was detected (p < 0.001). Additionally, significant odds ratios (ORs) were confirmed for all adjusted models. In women, the ORs in Model 1 without adjustment for potential confounders were 1.41 times (95% CI: 1.14–1.75) and demonstrated a significant result; however, the results were not significant in all adjusted models 2–4. Resultantly, a significant association was detected between dental caries and handgrip strength in Korean adults.

General health and oral health are very closely related. This study aimed to analyze the nutritional factors associated with the number of present teeth in Korean elderly adults. A total of 6,356 individuals were surveyed from the sixth Korean National Health and Nutrition Examination Survey conducted from 2013–2015. The number of existing teeth was divided into three categories: 0–10, 11–20, and over 21, and the nutrition survey covers eating habits, food frequency and food intake using face-to-face interviews. Multiple logistic regression analysis was performed to evaluate the association between nutrient intake and the number of existing teeth after adjusting for socio-demographic factors and general and oral health behaviors and status. As age increases, the number of teeth decreases. Individuals with more teeth had a significantly higher mean daily intake of protein, calcium, phosphorus, potassium and riboflavin (p < 0.05). After adjusting for sociodemographic factors in model 1 and the lower number of teeth in model 2, the strength of the association between the number of teeth and daily calcium intake remained significant. Statistically significant associations were present for dietary potassium intake in models 1 and 2 and in the 11–20 teeth group in model 3 (p < 0.05). We demonstrated a significant association between calcium and potassium intake and the number of teeth.

Parental attention and care is essential for children and adolescents who are unable to take care of their own oral health. There have been studies on the characteristics of mothers and the oral conditions of children in Korea, but there are very few previous studies that report on the oral health status of children according to the employment status of mothers. The aim of this study was to investigate the relationship between maternal employment and educational status and children’s oral health. Using data from the 10th Panel Study on Korean Children (PSKC), we analyzed the association between maternal employment and education status and the occurrence of dental caries among 1175 nine-year-old Korean children. The relationship was examined through cross-tabulation and logistic regression analysis. After adjusting for the mother’s age, parental style, parental relationship, family talk time, family meal time, leisure time, area of residence, and household income, the study found that children with working and studying mothers were 1.159 times more likely to have dental caries than children with non-working and non-studying mothers. The relationship between maternal employment and educational status and children’s oral health was confirmed. Based on the results of this study, it is expected that systematic follow-up studies will be needed to better understand the association and causal relationship between dental caries and oral disease in children according to whether mothers are employed or educated.

Habits formed during adolescence tend to persist into adulthood, and correcting poor habits or behaviors during this time is more effective than at other times. Particularly, parents and caregivers should encourage good hygiene habits in their adolescent children by setting a positive example themselves. Using logistic regression, we analyzed the association between brushing teeth after lunch and washing hands before lunch by family type among 54,848 adolescents from the 17th Youth Health Behavior Survey raw data in 2021. Four logistic regression models were used to adjust for confounders hierarchically. In all models, adolescents who practiced tooth brushing after lunch were 2.09 times more likely to practice hand washing before lunch than those who did not. With and without adjustment, we found that the association between adolescents’ tooth brushing and hand washing practices in two-parent households was stronger than the association between adolescents’ tooth brushing and hand washing practices in single-parent households. Associations were found between tooth brushing and hand washing practices, and these associations were higher among adolescents in two-parent households than among adolescents in single-parent households. The finding of a significant link between family type and personal hygiene habits indicates the need for interventions to enhance the oral health of children and adolescents. Such interventions should be customized to reflect the specific characteristics of the child’s household.