Effect of Periodontitis and Toothbrushing Frequency on Obesity Onset: A Cohort Study.

BACKGROUND The interplay between obesity and periodontitis has been widely examined. While obesity was reported as a risk factor for periodontitis, the inverse relationship is still little explored. Therefore, we aimed to determine whether periodontitis and toothbrushing frequency affect the onset of obesity. MATERIAL AND METHODS This cohort study included 1619 employees of a business enterprise headquartered in Tokyo, who in 2002 and 2006 underwent in prescribed annual health checks, both general and dental-specific, and who were not obese in 2002 (body mass index <25). The response variable was obesity (or absence) at 4 years, while the explanatory variables were presence/absence of periodontal pockets and toothbrushing frequency in 2002; their relationships were examined by multiple logistic regression analysis. RESULTS Subjects with periodontal pockets >/=4 mm showed a significantly higher odds ratio (OR) for onset of obesity at 4 years than those without periodontal pockets [OR: 1.59, 95% CI (confidence interval): 1.08-2.35, p<0.05]. Similarly, subjects who brushed their teeth >/=3 times/day had a significantly lower obesity OR than those who brushed </=1 time/day (OR: 0.49, 95% CI: 0.28-0.85, p<0.01). CONCLUSIONS The presence of periodontal pockets and toothbrushing frequency are significantly associated with the onset of obesity. Periodontal pockets >/=4 mm are associated with increased risk of obesity, while frequent toothbrushing (>/=3 times/day) appears to reduce the risk of obesity.