A longitudinal study on the relationship between dental health and metabolic syndrome in Japan

Background A close relationship has been reported between metabolic syndrome (MetS) and periodontitis. However, as there are only a few longitudinal studies, the association between MetS and periodontitis has not been fully elucidated. The aim of the present study was to investigate the relationships between periodontal conditions and internal changes in MetS components using a longitudinal analysis. Methods A total of 985 out of 2716 individuals who underwent systemic medical checkups in 2014 and 754 out of 2454 in 2016 received dental checkups including Community Periodontal Index. Of these, 390 individuals underwent medical and dental checkups in 2014 and 2016 and were included and reviewed. Results Of the 390 individuals, the positive number of MetS components decreased in 62 individuals (15.9%) and increased in 104 (26.7%). A multivariate analysis identified sex (risk ratio (RR): 0.55, 95% confidence interval (CI): 0.37-0.82, P < 0.05), alcohol intake (RR:2.06, 95%CI:1.14-3.73, P < 0.05), and the mediation of glycemia (RR:6.45, 95%CI:1.45-27.9, P < 0.01) as significant influencing factors for MetS. The number of MetS components was higher in individuals with persistent or progressive periodontitis than in those with no/improved periodontitis (RR:1.75, 95%CI:1.14-2.70, P < 0.01)). Improvements in periodontitis had a significant positive impact on MetS components, including hypertension (RR:2.14, 95%CI:1.03-4.43, P < 0.05) and hyperglycemia (RR:2.52, 95%CI:1.27-4.98, P < 0.01), but a negative impact on hypertension. Conclusions The results of the present study suggest that since the prevalence of individuals with more positive MetS components was higher in those with persistent/progressive periodontitis than in those with no/improved periodontitis, reducing periodontitis may be important for preventing pre-MetS and MetS.