Temporal sequence of the bidirectional relationship between hyperglycemia and periodontal disease: a community-based study of 5,885 Taiwanese aged 35–44 years (KCIS No. 32)

The relationship between hyperglycemia (including diabetes) and periodontal disease (PD) has been noted previously, but its temporal sequence in the same study based on a population-based study has been barely addressed. Our study sought to clarify temporal bidirectional relationships between both diseases among Taiwanese aged 35–44 years. A prospective follow-up cohort study was designed by following over time the two normal cohorts (PD-free or hyperglycemia-free) derived from 5,885 subjects aged 35–44 years who were periodically attending a screening program. We ascertained both incident cases of PD (defined by Community Periodontal Index score ≧ 3) and hyperglycemia [fasting plasma glucose (FPG) ≧100 mg/dL] or type 2 diabetes (FPG ≧ 126 mg/dL) with 5-year follow-up. Cox proportional hazards regression model was used to assess the effect of PD on hyperglycemia and vice versa with adjustment for other confounding factors. Participants with PD presented a 33 % increase in their risk of incident hyperglycemia (including diabetes) [adjusted hazard ratio (aHR) = 1.33 (95 % CI 1.09–1.63)] after controlling for potential confounding factors. Conversely, prediabetes and type 2 diabetes mellitus led to a significant elevated risk for PD [aHR = 1.25 (95 % CI 1.00–1.57) and aHR = 1.95 (95 % CI 1.22–3.13)] after adjustment for other confounding factors. In conclusion, a significant bidirectional relationships was found between hyperglycemia and PD, suggesting that both diseases may share common latent traits and pathways that are worthy of being further elucidated by continuing a long-term follow-up of this cohort.