Kernohan AFB et al. (2006) Effects of low-dose continuous combined hormone replacement therapy on glucose homeostasis and markers of cardiovascular risk in women with type 2 diabetes. Clin Endocrinol [doi:10.1111/j.1365-2265.2006.02679.x]

Observational studies suggested that hormone-replacement therapy (HRT) has a cardioprotective effect in postmenopausal women with type 2 diabetes, but the results of randomized, controlled trials indicated that conventional HRT might, in fact, increase cardiovascular risk. Researchers in the UK, therefore, evaluated the effect of low-dose HRT on cardiovascular risk factors and glucose metabolism in 28 women (mean age 62 years) with type 2 diabetes.

Participants were randomly allocated to receive once-daily tablets that contained either HRT (1 mg 17β estradiol and 0.5 mg norethisterone) or placebo. At 3 months, a substantial decrease from baseline was observed in fasting plasma glucose level (−9.4% versus +2.3%, respectively) and in total cholesterol (−13.7% versus +1.0%, respectively) in HRT-treated women compared with placebo-treated women. No significant difference was observed between the groups in relation to endogenous glucose production, hyperinsulinemic suppression of glucose production, glucose clearance rate, or levels of glycated hemoglobin, C-reactive protein, or triglycerides.

The authors conclude that continuous, low-dose HRT has beneficial effects on fasting glucose and cholesterol levels in postmenopausal women with type 2 diabetes, without the adverse effects (increased glucose clearance, triglycerides and C-reactive protein levels) seen with conventional HRT. The conclusions of the study are limited by the small sample size, however. Given the potential benefits and the possible risks associated with conventional HRT, the authors believe that the results of this study warrant a large-scale trial of low-dose HRT, in women with and without diabetes.