1.
Plasma sex steroid hormones and risk of developing type 2 diabetes in women: a prospective study.
Ding, EL, Song, Y, Manson, JE, Rifai, N, Buring, JE, Liu, S
Diabetologia. 2007;(10):2076-84
Abstract
AIMS/HYPOTHESIS Prospective data directly investigating the role of endogenous sex hormones in diabetes risk have been scant, particularly in women. We aimed to examine comprehensively plasma sex hormones in connection with risk of developing type 2 diabetes in postmenopausal women. METHODS We conducted a prospective, nested case-control study of plasma oestradiol, testosterone and dehydroepiandrosterone sulfate and risk of type 2 diabetes in a cohort of women health professionals with a mean age of 60.3 and 12.2 years since menopause. Among women not using hormone therapy and free of baseline cardiovascular disease, cancer and diabetes, 359 incident cases of type 2 diabetes were matched with 359 controls during an average follow-up of 10 years. RESULTS Oestradiol and testosterone were each strongly and positively associated with risk of type 2 diabetes. After adjustment for BMI, family history, lifestyle and reproductive variables, the multivariable relative risks (95% CI) comparing the highest vs lowest quintile were 12.6 (2.83-56.3) for total oestradiol (p = 0.002 for trend), 13.1 (4.18-40.8) for free oestradiol (p < 0.001 for trend), 4.15 (1.21-14.2) for total testosterone (p = 0.019 for trend) and 14.8 (4.44-49.2) for free testosterone (p < 0.001 for trend). These associations remained robust after adjusting and accounting for other metabolic syndrome components and baseline HbA(1c) levels. CONCLUSIONS/INTERPRETATION In postmenopausal women, higher plasma levels of oestradiol and testosterone were strongly and prospectively related to increased risk of developing type 2 diabetes. These prospective data indicate that endogenous levels of sex hormones may play important roles in the pathogenesis of type 2 diabetes. ClinicalTrials.gov ID no.: NCT00000479.
2.
Vitamin E and risk of type 2 diabetes in the women's health study randomized controlled trial.
Liu, S, Lee, IM, Song, Y, Van Denburgh, M, Cook, NR, Manson, JE, Buring, JE
Diabetes. 2006;(10):2856-62
Abstract
We directly assessed the efficacy of vitamin E supplements for primary prevention of type 2 diabetes among apparently healthy women in the Women's Health Study randomized trial. Between 1992 and 2004, 38,716 apparently healthy U.S. women aged >or=45 years and free of diabetes, cancer, and cardiovascular disease were in two randomly assigned intervention groups and received 600 IU of vitamin E (alpha-tocopherol, n = 19,347) or placebo (n = 19,369) on alternate days. During a median 10-year follow-up, there were 827 cases of incident type 2 diabetes in the vitamin E group and 869 in the placebo group, a nonsignificant 5% risk reduction (relative risk [RR] 0.95 [95% CI 0.87-1.05], P = 0.31). There was no evidence that diabetes risk factors including age, BMI, postmenopausal hormone use, multivitamin use, physical activity, alcohol intake, and smoking status modified the effect of vitamin E on the risk of type 2 diabetes. In a sensitivity analysis taking compliance into account, women in the vitamin E group had an RR of 0.93 (95% CI 0.83-1.04) (P = 0.21) compared with those randomized to placebo. In this large trial with 10-year follow-up, alternate-day doses of 600 IU vitamin E provided no significant benefit for type 2 diabetes in initially healthy women.