Sleep time and duration are associated with periodontitis in a representative sample of Koreans

Abstract Background So far, studies on the association between sleep and periodontitis have shown conflicting results. This study assessed the association among sleep duration, sleep time, and periodontitis among a nationally representative Korean population and the mediation effect of WBC. Methods We analyzed data from the Seventh Korean National Health and Nutrition Examination Survey (KNHANES VII) collected from 2016 to 2018. With the screenings by age (45 to 64), edentate, and the adequacy of information provided, the analysis was confined to a selected group of respondents of 4407 with measurements for the sleep survey and periodontal health status out of total 24,269. Periodontitis was defined according to the World Health Organization's community periodontal index (CPI) code greater than or equal to three, and severe periodontitis was defined as CPI code 4. Multivariable logistic regression analysis was used to test the association between sleep and periodontitis controlling the confounding factors. Results Those who went to bed during the daytime were associated with periodontitis (OR = 1.49, 95% confidence interval [CI]: 1.07 to 2.07). In a combined sleep time and duration model, those who went to bed at night with a sleep duration of 9 hours or more were associated with periodontitis (OR = 1.69, 95% CI: 1.04 to 2.77) and severe periodontitis (OR = 1.88, 95% CI: 1.02‐3.45). WBC count had the highest impact on the association between sleep time and periodontitis. Conclusions Our findings suggest that an extra‐long sleep duration and going to bed during the daytime are associated with periodontitis.