Association between erectile dysfunction and relative fat mass in adult men in the United States

Background: Obesity has been identified as a significant risk factor for erectile dysfunction (ED) in men, and the role of relative fat mass (RFM), a novel and potentially more accurate indicator of obesity, remains underexplored in this context. This study aimed to examine the association between RFM and ED using data from the National Health and Nutrition Examination Survey (NHANES) and to investigate the mediating effects of hypertension, cholesterol levels, and inflammatory markers in this relationship. Methods: Data were sourced from two cycles of NHANES (2001–2002 and 2003–2004), comprising a total of 3,449 adult male participants aged 20 years and above. After adjusting for sociodemographic factors (e.g., age, race, education level) and additional ED-related covariates, the association between RFM and ED was evaluated through multivariate logistic regression models and subgroup analyses. A smoothing curve fitting approach was applied to explore potential nonlinear relationships between RFM and ED. Mediation analysis further examined the mediating roles of hypertension, total cholesterol, white blood cell count, and C-reactive protein levels. Results: The mean age of participants was 49.51±18.13 years, with an ED prevalence of 27.46%. A statistically significant association was observed between RFM and ED (P<0.05). In the fully adjusted model (model 3), each unit increase in RFM corresponded to a 4.6% rise in ED prevalence [odds ratio (OR) =1.046; 95% confidence interval (CI): 1.007–1.087; P=0.02]. A U-shaped relationship between RFM and ED was identified through smoothing curve analysis, with a turning point at an RFM level of 29.01. Hypertension and total cholesterol mediated 12.46% and 14.63% of the effect, respectively. Conclusions: These findings suggest that RFM is associated with ED among adult men in the United States, with significant mediation effects via hypertension and cholesterol levels. Prospective longitudinal studies are warranted to further elucidate the role of RFM in ED development.