The Association Between a Body Shape Index and Testosterone Among U.S. Adult Males: National Health and Nutrition Examination Survey (2011–2016)

Background: Obesity, a prevalent global health issue, is associated with testosterone deficiency (TD). A body shape index (ABSI) provides a more precise assessment of obesity and visceral fat, but its relationship with testosterone remains unclear. This study aimed to explore the association between ABSI and testosterone levels leading to TD. Methods: Data from 5256 adult males participating in the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2016 were collected to analyze of the association between ABSI and TD. The data underwent analysis using multivariate linear regression, logistic regression, restricted cubic spline (RCS) analysis, subgroup analysis, and interaction testing. The predictive ability of ABSI based on weight, height, and waist circumference, as well as body mass index (BMI) based on weight and height, alongside a multiplicative combination of both metrics, BMI × ABSI, and optimal proportional combination OBMI + ABSI for assessing TD risk, was valuated using receiver operating characteristic (ROC) curves. Results: Following adjustment for all confounding factors, ABSI exhibited a negative linear correlation with testosterone (β = –6.99, 95% confidence interval (CI): –8.25 to –5.73; p < 0.001) and a positive association with TD risk (odds ratio (OR) = 1.06, 95% CI: 1.04–1.08; p < 0.001). Notably, these associations remained consistent in the subgroup analysis. Additionally, age and hypertension demonstrated significant interactions between ABSI and TD (p < 0.05). Moreover, combining metrics, such as BMI × ABSI and OBMI + ABSI, proved to be more reliable predictors of TD compared to BMI or ABSI alone. Conclusions: This study identified a negative linear correlation between ABSI and total testosterone levels in adult American males, as well as a positive linear correlation with TD prevalence. ABSI represents a valuable addition to BMI for assessing obesity and the association between obesity and TD.