Comprehensive Analysis of the Association Between Sex Hormones and Body Mass Components Among Men Adults: Results From a Large Population-Based Study.

Background: As the human body ages, adverse body composition status such as sarcopenia and obesity become obvious phenotypes which can cause numerous health problems. We aimed to comprehensively investigate the association of sex hormones and body mass components in adult men of various age groups.

Methods: We analysed national representative population data from the US National Health and Nutrition Examination Survey. Generalized linear model regression analyses were used to evaluate the association between sex hormones (total testosterone [TT], bio-available testosterone [BT], sex hormone-binding globulin [SHBG], estradiol [E₂] and testosterone to estradiol ratio [T/E ratio]) and body mass components (weight, body mass index (BMI), total lean mass, appendicular lean mass, bone mineral content, total fat and trunk fat). The collection and testing time of blood samples were not fixed and there was no strict fasting, but in subsequent analysis we used statistical methods to minimize the impact of random testing.

Results: After screening for inclusion and exclusion, 3759 male participants aged 20-85 years old were included in this study. Higher levels of TT, SHBG, BT and T/E ratios were significantly associated with higher total lean mass, appendicular lean mass and bone mineral content, while lower weight, BMI, total fat and trunk fat. For E₂ levels in men, we found an opposite trend, with higher E₂ levels significantly associated with lower total lean mass and appendicular lean mass, and higher weight, BMI, total fat and trunk fat. Notably, in subgroup analysis, the results showed that there were significant interaction effects of age and smoking history in the association between sex hormones and body mass components.

Conclusion: Higher TT levels, BT levels, SHBG levels and T/E ratios are associated with lower body weight and improved body composition in young adult men (characterized by higher lean body mass, higher bone density and lower fat mass). The relationship is especially pronounced among relatively young, nonsmoking men.