Association between Findings in Oral Health Screening and Body Mass Index: A Nation-Wide Longitudinal Study

Oral diseases, such as periodontitis and dental caries, can cause systemic inflammation as well as local effects, which is an important contributing factor for obesity. We aimed to investigate the change in body mass index (BMI) according to the presence of periodontitis and oral hygiene indicators. This study enrolled 110,068 participants from the national health screening cohort in Korea from 2009–2010 who underwent an oral health checkup. As oral hygiene indicators, the presence of periodontitis, dental caries, tooth loss, and tooth brushing were assessed. We constructed a linear mixed model for BMI. BMI was repeatedly measured in the health examination until 2015. In the multivariate linear mixed model for BMI, the presence of periodontitis (β = 0.0687, standard error (SE) = 0.0225, p = 0.002), dental caries (β = 0.0735, SE = 0.0152, p < 0.001), and tooth loss (β = 0.1328, SE = 0.0175, p < 0.001) were positively associated with BMI. In contrast, frequent tooth brushing (≥3 times/day) was negatively associated with BMI (β = −0.2610, SE = 0.0306, p < 0.001). The presence of periodontitis, dental caries, and tooth loss may be associated with higher BMI, whereas frequent tooth brushing may be related to lower BMI. Better oral hygiene might be associated with lower BMI. Further study is needed to determine the effect of oral health behavior and dental disease on obesity.