Sex-specific associations between masticatory muscles, teeth, periodontitis, and adiposity

OBJECTIVE: The relationship between body fat and the masticatory muscles has rarely been investigated. In this study, we aimed to investigate sex-specific interactions among teeth, periodontitis, and masticatory muscles in relation to adiposity measures. METHODS: This study included 665 participants aged 30-93 years from the population-based Study of Health in Pomerania (SHIP-2) follow-up. The cross-sectional areas of the masseter and pterygoid muscles were measured using magnetic resonance imaging (MRI); and anthropometric data were collected at baseline (SHIP-0) and after 10 years (SHIP-2). Regression analyses and adiposity impact models were used to examine sex-specific associations. RESULTS: The cross-sectional areas of the masticatory muscles were positively associated with body mass index (BMI) and waist circumference (WC). In men, the medial pterygoid muscle was primarily associated with adiposity indicators (p < 0.001). Masseter muscle area was related to BMI and WC in both sexes, with WC attenuating the association with BMI. The positive association between the number of teeth and masticatory muscle areas was significant in both sexes (p < 0.001), whereas clinical attachment loss was negatively associated with adiposity only in women. The lateral pterygoid muscle was not associated with adiposity. Furthermore, gains in BMI and WC over the 10-year follow-up were associated with the masseter and medial pterygoid muscles in men (p < 0.001), but not in women (p > 0.30). A sensitivity analysis restricted to participants with more than 20 teeth confirmed the results for the complete cohort. CONCLUSIONS: Masticatory muscles are associated with adiposity characteristics, presumably by modulating masticatory performance. These relationships were sex-specific and differed significantly depending on whether BMI or WC was evaluated.