Conflicting evidence suggests a link between diabetes-related microvascular complications and periodontitis. Reliable estimates have been hindered by small sample sizes and residual confounding. Moreover, the combined effects of microvascular complications and dyslipidemia on periodontitis have not been explored. Therefore, this study aimed to investigate the association between individual and combined diabetic microvascular complications (i.e., neuropathy and retinopathy) and moderate/severe periodontitis in a Danish population-based study. In addition, we assessed whether dyslipidemia modified these associations. This study comprised 15,922 participants with type 2 diabetes from the Health in Central Denmark study. Multinomial logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for individual and joint microvascular diabetes complications. The models adjusted for potential confounders, including sociodemographic factors, lifestyle behaviors, and health conditions. Inverse probability of treatment weighting (IPTW) balanced measured confounders between periodontitis and nonperiodontitis participants. Sensitivity analyses tested the findings' robustness by estimating E-values for unmeasured confounding and varying microvascular complication definitions. After IPTW, adjusted models revealed that diabetic neuropathy (OR 1.36, 95% CI 1.14 to 1.63) and retinopathy (OR 1.21, 95% CI 1.03 to 1.43) were significantly associated with moderate/severe periodontitis. Moreover, the coexistence of microvascular complications increased the odds 1.5-fold for moderate/severe periodontitis (OR 1.51, 95% CI 1.23 to 1.85). An effect modification of dyslipidemia on an additive scale was found, indicated by a positive relative excess risk due to interaction of 0.24 for neuropathy, 0.11 for retinopathy, and 0.44 for both complications. Sensitivity analysis ruled out unmeasured confounders and microvascular complication definitions as explanatory factors. Diabetic neuropathy and retinopathy, individually and combined, were associated with moderate/severe periodontitis. In addition, dyslipidemia had an additive positive effect modification on diabetic microvascular complications, elevating the odds of moderate/severe periodontitis. These findings may aid in identifying at-risk subgroups for diabetes-related microvascular complications and periodontitis, optimizing efforts to mitigate disease burden.

Periodontitis and Diabetes Complications: A Danish Population-Based Study