This systematic review indicates that endogenous sex hormones may differentially modulate glycemic status and risk of type 2 diabetes in men and women. High testosterone levels are associated with higher risk of type 2 diabetes in women but with lower risk in men; the inverse association of SHBG with risk was stronger in women than in men.

BACKGROUND-Circulating sex hormone-binding globulin levels are inversely associated with insulin resistance, but whether these levels can predict the risk of developing type 2 diabetes is uncertain.

Ruth Loos and colleagues report findings from a meta-analysis of multiple studies examining the extent to which physical activity attenuates effects of a specific gene variant, FTO, on obesity in adults and children. They report a fairly substantial attenuation by physical activity on the effects of this genetic variant on the risk of obesity in adults.

Background Vitamin D status has been linked to the risk of cardiovascular disease (CVD). However, the optimal 25hydroxy-vitamin D (25(OH)-vitamin D) levels for potential cardiovascular health benefits remain unclear. Methods and Results We searched MEDLINE and EMBASE from 1966 through February 2012 for prospective studies that assessed the association of 25(OH)-vitamin D concentrations with CVD risk. A total of 24 articles met our inclusion criteria, from which 19 independent studies with 6,123 CVD cases in 65,994 participants were included for a meta-analysis. Comparing the lowest to the highest 25(OH)-vitamin D categories, the pooled relative risks (RR) was 1.52 (95% CI: 1.30-1.77) for total CVD, 1.42 (95% CI: 1.19-1.71) for CVD mortality, 1.38 (95% CI: 1.21-1.57) for coronary heart disease, and 1.64 (95% CI: 1.27-2.10) for stroke. These associations remained strong and significant when analyses were limited to studies that excluded participants with baseline CVD and had better controlled for season and confounding. We used a fractional polynomial spline regression analysis to assess the linearity of dose-response association between continuous 25(OH)-vitamin D and CVD risk. The CVD risk increased monotonically across decreasing 25(OH)-vitamin D below approximately 60 nmol/L, with a RR of 1.03 (95% CI: 1.00-1.06) per 25 nmol/L decrement in 25(OH)-vitamin D. Conclusions This meta-analysis demonstrated a generally linear, inverse association between circulating 25(OH)-vitamin D in the range of 20-60 nmol/L and risk of CVD. Further research is needed to clarify the association of 25(OH)-vitamin D higher than 60 nmol/L with CVD risk and assess causality of the observed associations.