Association between adiposity and cognitive function in young men: Hormonal mechanisms.
OBJECTIVE
To determine the association between adiposity, hormones, and cognition in young men with abdominal obesity.


METHODS
In this cross-sectional observational study, 53 nondiabetic men with abdominal obesity (mean body mass index, 37.3 kg/m(2) ; age, 22-45 years) and normal intelligence underwent detailed measures of body composition, hormonal profiles, and cognition. Age- and education-adjusted performance in five cognitive domains was examined.


RESULTS
Total fat percentage was negatively associated with visuospatial skills (P = 0.002) and visual memory (P = 0.012). Insulin resistance (homeostatic model assessment of insulin resistance) was also negatively associated with these domains (P = 0.05 and trend, P = 0.06, respectively). Total testosterone levels were negatively associated with executive function and verbal learning and memory (P = 0.04 for each), but free testosterone was not. Sex hormone-binding globulin (SHBG) was also inversely associated with performance in these domains (P = 0.015 and trend, P = 0.09, respectively). In a stepwise regression model including percentage fat, homeostatic model assessment of insulin resistance, SHBG, and free testosterone, SHBG was the only variable selected for executive function (P = 0.05) and showed a trend for verbal learning and memory (P = 0.09).


CONCLUSIONS
Adiposity and insulin resistance were associated with worse function in visual domains. An unexpected negative association is reported between SHBG and cognitive measures, which seemed to be independent of free testosterone levels.