Total Water Intake and Periodontitis in Korean Adults: Evidence from a Nationally Representative Survey.

PURPOSE: This study investigated the association between total water intake (TWI) and periodontitis among Korean adults and examined whether this relationship differed according to dietary sodium intake. MATERIALS AND METHODS: Nationally representative data from adults aged ≥19 years (n = 9547) who participated in the 7th Korea National Health and Nutrition Examination Survey (KNHANES 2016-2018) were analyzed. Total water intake, representing overall hydration exposure from foods, beverages, and drinking water, was estimated using a 24-h dietary recall. Periodontitis was defined as a Community Periodontal Index score ≥3. Dietary sodium intake was categorized as ≤2000 or >2000 mg/day according to World Health Organization recommendations. Multivariable logistic regression analyses accounting for the complex survey design were performed, with sequential adjustment for sociodemographic factors, health behaviors, and systemic conditions. Stratified analyses were conducted by sodium intake level. RESULTS: Lower total water intake was consistently associated with higher odds of periodontitis. After full adjustment, individuals with the lowest TWI (≤500 ml/day) had significantly greater odds of periodontitis compared with those with higher intake (≥1500 ml/day; odds ratio [OR] 1.42, 95% confidence interval [CI] 1.15-1.76). This association was evident primarily among participants with high dietary sodium intake (>2000 mg/day; OR 1.42, 95% CI 1.09-1.84), whereas no statistically significant association was observed in the low-sodium group. CONCLUSION: Lower total water intake is associated with increased odds of periodontitis in Korean adults, particularly among individuals consuming high levels of dietary sodium. These findings are hypothesis-generating and suggest that promoting adequate daily water intake warrants further investigation as a potential modifiable strategy for periodontal health, particularly in populations with high sodium consumption.