Background Type 2 diabetes mellitus is associated with a high prevalence of oral health problems. However, few longitudinal studies have examined the influence of oral health problems on incident diabetes. This study investigated the prospective associations between oral health and development of type 2 diabetes.

Methods Data are based on a longitudinal cohort, the British Regional Heart Study (BRHS), comprising men originally recruited in 1978–80, aged 40–59 years, from 24 towns across Britain. Data for this analysis are from physical examination of the BRHS participants conducted in 2010–12 at 71–92 years (n=2147) and questionnaire Physical oral health examination included tooth loss and periodontal disease. Subjective oral health measures included dry mouth, self-rated oral health, and denture use (and related problems). Follow-up for incidence of type 2 diabetes was through GP records over a 9-year period from 2010–12. Cox regression models were used for the analysis. Prevalent cases of type 2 diabetes were excluded from the models. Age, body mass index (BMI), social class, smoking, alcohol consumption, and physical activity were adjusted for in the fully adjusted model.

Results Among 1908 men without prevalent diabetes in 2010–12, 78 new cases of diabetes occurred in the 9-year follow-up period. In the fully adjusted models, tooth loss, poorer self-rated oral health and denture wearing were associated with increased (?) risks of developing diabetes. After adjustment for all potential confounders, complete tooth loss (edentulism) was associated with an increased risk of incident diabetes (hazard ratio (HR) =3.44, 95% CI 1.74–6.81) compared with having at least 21 natural teeth; poor/fair self -rated oral health compared with excellent/good self-rated oral health was associated with an increased risk of incident diabetes (adjusted HR=2.37, 95%CI 1.45–3.90); denture wearing among those with no natural teeth was associated with an increased risk of incident diabetes (adjusted HR = 2.56, 95% CI 1.33–4.94) compared with men with natural teeth (no dentures).

Conclusion These findings suggest that markers of poor oral health in older adults are associated with a greater risk of developing type 2 diabetes. The results highlight the potential influence of oral health on diabetes in later life. Improving oral health may reduce the risk of developing diabetes even in older ages.