Association of Metabolic Obesity Phenotypes and Total Testosterone in Chinese Male Population

Objective Obesity and metabolic syndrome have been reported to exert an impact on the male reproductive system with decreasing levels of serum total testosterone (TT); however, the effect of different metabolic obesity phenotypes on testosterone has been poorly studied. We aimed to evaluate the association of metabolic obesity phenotypes and total testosterone levels in a Chinese male population. Methods We performed a retrospective study based on an epidemiological investigation, a total of 4,081 male individuals aged from 40-75 years old were recruited. The population was classified as metabolically healthy normal weight (MHNW), metabolically healthy overweight/obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy overweight/obese (MUO) according to normal weight (BMI<25.0) and overweight/obesity (BMI≥25.0) with or without metabolic syndrome. Results We collected 563 hypotestosteronemia among 4,081 male individuals. The odds ratios (ORs) (95% CIs) of hypotestosteronemia in obesity and metabolic syndrome were 3.072 (2.414-3.911) and 3.294 (2.631-4.125), respectively, after adjusting for age, luteinizing hormone, smoking status, and alcohol consumption. Compared to the MHNW group, male subjects in MHO, MUNW, and MUO groups had decreased serum TT levels. Additionally, the MUO group had a lowest concentration of serum TT and a highest proportion of hypotestosteronemia. There was no significant difference of TT levels between the MHO and MUNW groups. Conclusion Obesity and metabolic syndrome are independent risk factors of hypotestosteronemia in Chinese male populations. Our study also suggested that individuals with MHO, MUNW, and MUO have a higher risk of developing hypotestosteronemia.