A nationwide registry-based cohort study of the association between childhood dental caries and gingivitis with type 2 diabetes in adulthood.

Background: Evidence suggests a bidirectional relationship between oral health status and type 2 diabetes (T2D) in adults. Studies on associations between childhood oral health and T2D in adulthood are lacking.

Methods: This is a nationwide Danish registry-based cohort study of individuals born between 1963 and 1972, having at least one registration in the National Child Odontology Registry between 1972 and 1987 (n = 627,758). Follow-up lasted from 1995 to 2018. Main exposure variables were the highest achieved levels of dental caries and gingivitis between 1972 and 1987. The outcome was T2D diagnosis during follow-up. Data was analyzed using Cox-regression, stratified on sex, with age as the underlying timescale and highest achieved level of education between age 25-30 years as Cox-strata. Main analyses were conducted with and without age-restrictions (T2D diagnosis before/after age 40).

Results: Compared to lowest-level references, high levels of gingivitis associated with increased hazard ratios (HRs) of T2D in both males (HR [95% confidence interval]: 1.59 [1.47; 1.72]) and females (1.87 [1.68; 2.08]), as did severe dental caries (males: (1.15 [1.04; 1.27], in females: 1.19 [1.06; 1.35]). Below age 40, gingivitis associated with increased HRs in males (1.84 ([1.58; 2.15]) and females (1.94 [1.63; 2.30]). Above age 40, both exposures displayed higher HRs in males (high gingivitis: 1.52 [1.39; 1.66] vs. severe caries: 1.23 [1.09; 1.38]) and females (1.83 [1.59; 2.10] vs. 1.37 [1.17; 1.59]).

Conclusions: Data suggest an association between childhood dental caries and gingivitis with risk of receiving a T2D diagnosis in adulthood. However, results are affected by residual confounding warranting further studies.