Sex Differences of Sex Hormones in Type 2 Diabetes: Implications for Sex-based Medicine

[Epidemiologic Inquiry 2006, 1: 18]

Recently, the theme of sex/gender-based medicine has been emerging as an ever more prevalent theme in clinical medicine. Thus, this also forces researchers to also ponder and consider sex-based epidemiologic investigations more carefully.

In last week's issue of JAMA, Ding et al. investigated sex differences of how plasma sex hormones affect risk of type 2 diabetes. From a systematic review of cross-sectional and prospective studies and randomized trials, it was consistently found that testosterone increased the risk of type 2 diabetes in women, but testosterone had opposite effects in men by decreasing the risk of type 2 diabetes. Additionally, the binding protein, sex hormone-binding globulin, was found to be strongly protective in women, but only marginally protective against type 2 diabetes in men.

Given such innate sex differences in action of one the most fundamental sex hormones, there is now strong biologic plausibility of sex differences in a wide variety of other etiologic pathways for disease, not just related to diabetes and its associated morbidities. Thus, perhaps epidemiologists and other clinical investigators should more carefully examine future exposure-disease relationships stratifying on sex and assessing sex-specific associations, rather than just adjusting for sex and giving little notice to sex interactions.

~The Editors

Reference: Ding EL, Song Y, Malik VS, Liu S. Sex differences of endogenous sex hormones and risk of type 2 diabetes: a systematic review and meta-analysis. JAMA. 2006 Mar 15;295(11):1288-99.