Abstract
ObjectiveRandomized trials in men with testosterone deficiency have provided evidence of short‐term effects of testosterone therapy on muscle and fat mass but it is unclear whether this persists over a longer period or how testosterone affects women. We examined whether the midlife decline in testosterone relates to fat and lean mass in both sexes.MethodsData were collected from 440 men and 560 women participating in the 1946 British birth cohort study with testosterone measured at 53 and/or 60‐64 years. Fat and appendicular lean mass were measured at 60‐64 years using dual‐energy X‐ray absorptiometry.ResultsMean free testosterone concentrations were lower at 60‐64 than 53 years, by 26% in both sexes. At both ages testosterone was negatively associated with fat mass in men and positively associated in women. A larger decline in free testosterone was associated with higher fat mass in men but with lower fat mass among women. In contrast, declines in testosterone were not associated with lean mass in either sex.ConclusionsOur findings suggest sex‐divergent relationships between testosterone and fat mass and their distribution but do not support the hypothesis that midlife declines in testosterone lead to lower lean mass.
Highlights
Testosterone is known to have a number of important regulatory roles in adults, and its decline observed during aging [1,2] may adversely affect physical health and functioning via gains in fat and losses in lean mass [3,4]
Mean total and free testosterone were higher in men than women, while women had higher sex-hormone binding globulin (SHBG) concentrations (P < 0.001 in all cases)
Mean free testosterone declined, while SHBG slightly increased in men and declined in women
Summary
Testosterone is known to have a number of important regulatory roles in adults, and its decline observed during aging [1,2] may adversely affect physical health and functioning via gains in fat and losses in lean (muscle) mass [3,4]. Experimental studies have shown that testosterone supplementation in men with low testosterone concentrations leads to gains in muscle [7] and losses in fat mass [8,9]. Diet- or bariatric surgery-induced weight loss reverses the pathological suppression of testosterone levels in overweight/obese men [10], suggesting a bidirectional relationship between testosterone and fat mass. In contrast to these effects in men, rare reports of women undergoing sex change therapy suggest that testosterone supplementation may increase visceral fat mass [11]. Previous observational studies have mostly been crosssectional, usually only of men, and yielded inconsistent results [13]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
