Insulin resistance predicts the risk of gingival/periodontal inflammation

Objectives: Evaluate whether insulin resistance (IR) predicts the risk of oral inflammation, assessed as the number of sites with bleeding on probing (BOP) and number of teeth with probing pocket depths (PPD) >= 4 mm and BOP. Methods: Data on 870 overweight/obese diabetes free adults, aged 40-65 years from the San Juan Overweight Adults Longitudinal Study over a three-year period, was analyzed. Baseline IR, assessed using the Homeostasis Model Assessment of IR (HOMAIR) index, was divided into tertiles. BOP was assessed at buccal and lingual sites, and PPD at six sites per tooth. Negative binomial regression was used to estimate the risk ratios (RRs) for oral inflammation adjusted for baseline age, gender, smoking status, alcohol intake, education, physical activity, waist circumference, mean plaque index, and baseline number of sites with BOP, or number of teeth with PPD >= 4 mm and BOP. The potential impact of tertiles of serum TNF-alpha and adiponectin on the IR-oral inflammation association was also assessed in a subsample of 597 participants. Results: Participants in the highest HOMA-IR tertile at baseline had significantly higher numbers of sites with HOP [RR = 1.19, 95% confidence interval (CI): 1.031.36] and number of teeth with PPD >= 4 mm and BOP (RR = 1.39, 95% CI: 1.09-1.78) at follow-up, compared with individuals in the lower two HOMA-IR tertiles. Neither TNF-alpha nor adiponectin confounded the associations. Conclusion: IR significantly predicts gingival/periodontal inflammation in this population.