Serum Inhibin B and Cardiometabolic Profile in Adult Men: A Cross-Sectional Study

Background/Objectives: The extent to which inhibin B, a marker of Sertoli cell function, is affected by cardiometabolic disturbances remains insufficiently understood. The aim of this study was to evaluate the relationships between serum inhibin B levels and the atherogenic index of plasma (AIP), triglyceride-glucose (TyG) index, HOMA-IR, METS-IR, and C-reactive protein (CRP) in adult men aged 40-65 years and to secondarily investigate a possible association with coronary artery calcium score (CACS). Methods: This cross-sectional study included 67 men aged 40-65 years referred for coronary computed tomography angiography, sampled in a balanced manner across coronary artery calcium score (CACS) categories. Serum inhibin B levels were measured by a commercial sandwich ELISA; AIP, TyG index, HOMA-IR, and METS-IR were calculated from fasting biochemical measurements. Associations between inhibin B and cardiometabolic parameters were assessed using Spearman correlation analyses and age-adjusted partial correlations. Significant associations were further examined using multivariable linear regression. Results: The mean serum inhibin B level was 224 ± 35 pg/mL. The TyG index (ρ = -0.308, p = 0.011) and BMI (ρ = -0.348, p = 0.004) showed significant negative correlations with inhibin B, and both associations persisted after age adjustment. No significant associations were found with HOMA-IR, METS-IR, AIP, CRP, or CACS. Although BMI and the TyG index were not significantly correlated with each other (ρ = -0.084, p = 0.564), both variables remained independently associated with inhibin B in the multivariable model (TyG: β = -0.283, p = 0.015; BMI: β = -0.313, p = 0.007). The model explained 18.0% of the variance in inhibin B (R² = 0.180). Conclusions: In adult men, serum inhibin B levels were independently and inversely associated with BMI and the TyG index, whereas no significant relationship was observed with other metabolic, inflammatory, atherogenic, or coronary calcification markers. These findings suggest that the relationship between inhibin B and cardiometabolic health is not generalizable across all cardiometabolic indices and may be specifically related to the metabolic profile represented by adiposity and the TyG index.