(1) Background: To investigate the grouping of obesity and insulin resistance with caries and periodontitis from a syndemic perspective through pathways of socioeconomic inequalities, smoking, alcohol, and high sugar consumption in adolescence. (2) Methods: The population-based RPS Cohort study, São Luís, Brazil, in ages 18-19 years (n = 2515) was used. The outcomes were the grouping of pbesity and Insulin Resistance Phenotype (latent variable formed by Triglycerides/HDL ratio, TyG index, and VLDL) and the Chronic Oral Disease Burden (latent variable comprising caries, bleeding on probing, probing depth ≥ 4 mm, clinical attachment level ≥ 3 mm, and visible plaque index ≥ 15%). Socioeconomic Inequalities influencing the Behavioral Risk Factors (latent variable formed by added sugar, smoking, and alcohol) were analyzed using structural equation modeling. (3) Results: Socioeconomic Inequalities were associated with the Chronic Oral Disease Burden [Standardized Coefficient (SC) = 0.222, p < 0.001]. Behavioral Risk Factors were associated with increased Chronic Oral Disease Burden (SC = 0.103; p = 0.013). Obesity was associated with the Insulin Resistance Phenotype (SC = 0.072; p < 0.001) and the Chronic Oral Disease Burden (SC = 0.066; p = 0.005). The Insulin Resistance Phenotype and the Chronic Oral Disease Burden were associated (SC = 0.053; p = 0.032). (4) Conclusion: The grouping of obesity and early events of diabetes with caries and periodontitis call for a syndemic approach in adolescence.
Keywords: adolescents; caries; insulin resistance; obesity; periodontitis; syndemic.