Periodontal disease progression and glycaemic control among Gullah African Americans with type-2 diabetes

Aim: To evaluate associations between glycaemic control and periodontitis progression among Gullah African Americans with type-2 diabetes mellitus (T2DM). Materials and Methods: From an ongoing clinical trial among T2DM Gullah, we extracted a cohort previously in a cross-sectional study (N=88). Time from baseline (previous study) to follow-up (trial enrollment, before treatment interventions) ranged 1.93-4.08 years [mean=2.99, standard deviation (SD)=0.36]. We evaluated tooth site-level periodontitis progression [clinical attachment loss (CAL) worsening of ≥2 mm, periodontal probing depth (PPD) increases of ≥2 mm and bleeding on probing (BOP) from none to present] by glycaemic control status (well-controlled=HbA_1c<7%, poorly-controlled= HbA_1c ≥7%) using multivariable generalized estimating equations logistic regression, nesting tooth sites/person. Results: Poorly-controlled T2DM (68.18%) was more prevalent than well-controlled T2DM (31.82%). Proportions of tooth sites/person with CAL progression between baseline and follow-up ranged 0.00-0.59 (mean=0.12, SD=0.12), while PPD and BOP progression ranged 0.00-0.44 (mean=0.09, SD=0.11) and 0.00-0.96 (mean=0.24, SD=0.18), respectively. Site-level PPD at baseline was a significant effect modifier of associations between poorly-controlled T2DM and site-level CAL and PPD progression [adjusted odds ratios (OR) according to poorly-controlled T2DM among PPD at baseline=3, 5 and 7 mm, respectively: CAL progression=1.93, 2.64, and 3.62, PPD progression=1.98, 2.76, and 3.84; p<0.05 for all]. Odds of site-level BOP progression were increased (OR=1.24) for poorly-controlled T2DM, yet the results were not significant (p=0.32). Conclusions: These findings from a distinct, homogenous population further support the clinical relevance of identifying patients with poor glycaemic control and periodontitis, particularly among those with disparities for both diseases.