Obesity has deleterious effects on sexual and reproductive function in men, that have until relatively recently garnered limited attention. A predominantly visceral accumulation of adipose tissue, with associated metabolic abnormalities, induces a “functional secondary hypogonadism” characterised by low serum total testosterone (T) and sex hormone binding globulin concentrations and gonadotrophins in the mid- or low normal range. Such low T may accelerate progression of impaired glucose metabolism to type 2 diabetes. T increases proportionally to weight loss, which is the appropriate management.
Independent of testosterone men with obesity are also more likely to have erectile dysfunction and diminished sexual desire as well as abnormalities in the morphology and function of their sperm, high levels of reactive oxygen species (ROS) in seminal fluid, vulnerability of the sperm to oxidative damage and reduced pregnancy rates as compared to normal weight men. Epigenetic changes to sperm DNA and altered pattern of microRNA’s in sperm may result in the transmission of chronic disease risk to subsequent generations.
The extent to which these problems are attributable to obesity as such or associated comorbidities, dietary pattern, and other lifestyle behaviours, and/or environmental exposure, is unclear. Men who are socially disadvantaged (low income, unemployed, separated, victims of racial and ethnic disparity), located in rural and remote locations, and/or have limited functional health literacy have a higher risk of obesity associated comorbidities.