Association between meal timing regularity and oral health behaviors

Good oral health habits may be related to the regularity of food intake; however, these relationships have not been well-explored. This study examined the association between meal timing regularity and oral health behaviors, focusing on consistent weekday and weekend meal schedules. A cross-sectional study was conducted using data from 4,840 participants (3,290 men and 1,550 women) who underwent health checkups at the Seirei Preventive Health Center, Japan. Meal timing regularity (weekday lunch, weekday dinner, weekend lunch, and weekend dinner) was assessed using a self-administered questionnaire and categorized as regular or irregular. Oral health behaviors included tooth brushing frequency, use of interdental cleaning devices, and professional dental cleaning. Multivariable-adjusted logistic regression analyses assessed associations between meal timing regularity and oral health behaviors. The median age of participants was 53 years (range: 35‒69). The proportions of participants with irregular meal timing were 1.8% for weekday lunch, 1.4% for weekday dinner, 2.2% for weekend lunch, and 0.9% for weekend dinner. Irregular weekday dinner (Odds ratio [OR] = 2.05, 95% confidence interval [CI]: 1.19–3.54, p = 0.01), weekend lunch (OR = 2.28, 95% CI: 1.45–3.57, p < 0.001), and weekend dinner timings (OR = 2.09, 95% CI: 1.07–4.08, p = 0.031) were significantly associated with brushing less than twice daily. Irregular weekend dinner timing was also associated with less frequent use of interdental cleaning devices (OR = 2.25, 95% CI: 1.02–4.96, p = 0.044). After full adjustment, associations of weekday dinner and weekend lunch with tooth brushing remained significant, but those for weekend dinner (tooth brushing and interdental cleaning) were attenuated. No significant associations were observed between meal timing regularity and professional dental cleaning. Irregular meal timing, particularly on weekends, was associated with less frequent tooth brushing. The association with interdental cleaning was weaker and not robust after full adjustment. Regular meal timing may be a marker of stable daily routines relevant to oral health behaviors, although causal inference is not possible from this cross-sectional design.