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.