OBJECTIVE -To determine the prospective association between endogenous sex hormones and the development of type 2 diabetes in older men and women.RESEARCH DESIGN AND METHODS -A standardized medical history was obtained, an oral glucose tolerance test was performed, and plasma samples for sex hormones and covariates were collected from ambulatory, community-dwelling men and women at baseline from 1984 to 1987 . Approximately 8 years later (1992, another medical history was obtained, an oral glucose tolerance test was performed, fasting and 2-h insulin levels were measured, and the homeostasis model assessment for insulin resistance (HOMA-IR) was evaluated. This report is based on the 294 men and 233 women, aged 55-89 years, who completed both visits and who did not have diabetes as determined by history or glucose tolerance test at baseline, as well as women who were postmenopausal and not taking replacement estrogen.RESULTS -In age-adjusted correlation analyses, total testosterone was inversely and significantly related to subsequent levels of fasting and postchallenge glucose and insulin in men, whereas bioavailable testosterone and bioavailable estradiol were positively and significantly related to fasting and postchallenge glucose and insulin in women (all P Ͻ0.05). There was similar significant association with insulin resistance (HOMA-IR) in unadjusted and multiply adjusted analyses (P Ͻ0.05). There were 26 men and 17 women with new (incident) diabetes. The odds for new diabetes were 2.7 (95% CI 1.1-6.6) for men in the lowest quartile of total testosterone and 2.9 (1.1-8.4) for women in the highest quartile of bioavailable testosterone.CONCLUSIONS -Low testosterone levels in men and high testosterone levels in women predict insulin resistance and incident type 2 diabetes in older adults. Diabetes Care 25:55-60, 2002B oth human (1-9) and animal studies (10,11) show differences by sex in the effects of endogenous sex hormones on insulin resistance. In men, low plasma testosterone is associated with obesity, upper body fat distribution, and increased levels of glucose and insulin (1-3), whereas hyperandrogenicity is associated with an increased risk for type 2 diabetes and cardiovascular disease in women (3-9). Most of these studies were cross-sectional.Sex hormone-binding globulin (SHBG) is an indirect measure of androgenicity, because its concentration is mainly determined by free estrogen and testosterone (4,7-9,12,13). Several prospective studies show that low levels of testosterone and SHBG predict the development of type 2 diabetes in middle-aged (14,15) and elderly (16) men. One crosssectional study shows that women with type 2 diabetes have high levels of free testosterone and low levels of SHBG (17). Low levels of SHBG alone did not significantly predict incident type 2 diabetes in middle-aged men (18); in contrast, low levels of SHBG alone predicted the development of type 2 diabetes in women (18,19). To our knowledge, there are no large prospective, population-based studies of total and bioavailabl...

A higher consumption of anthocyanins and anthocyanin-rich fruit was associated with a lower risk of type 2 diabetes.

BackgroundCoffee consumption has been associated with a lower risk of type 2 diabetes in prospective cohort studies, but the underlying mechanisms remain unclear. The aim of this study was to evaluate the effects of regular and decaffeinated coffee on biological risk factors for type 2 diabetes.MethodsRandomized parallel-arm intervention conducted in 45 healthy overweight volunteers who were nonsmokers and regular coffee consumers. Participants were assigned to consumption of 5 cups (177 mL each) per day of instant caffeinated coffee, decaffeinated coffee, or no coffee (i.e., water) for 8 weeks.ResultsAverage age was 40 years and body mass index was 29.5 kg/m2. Compared with consuming no coffee, consumption of caffeinated coffee increased adiponectin (difference in change from baseline 1.4 μg/mL; 95% CI: 0.2, 2.7) and interleukin-6 (difference: 60%; 95% CI: 8, 138) concentrations and consumption of decaffeinated coffee decreased fetuin-A concentrations (difference: -20%; 95% CI: -35, -1). For measures of glucose tolerance, insulin sensitivity, and insulin secretion, no significant differences were found between treatment groups.ConclusionsAlthough no changes in glycemia and/or insulin sensitivity were observed after 8 weeks of coffee consumption, improvements in adipocyte and liver function as indicated by changes in adiponectin and fetuin-A concentrations may contribute to beneficial metabolic effects of long-term coffee consumption.Trial Registrationclinicaltrials.gov NCT00305097

Background: Data concerning the long-term association between nut consumption and weight change in a free-living population are sparse. Objective: The objective was to determine the relation between nut consumption and long-term weight change. Design: The participants were 51,188 women in the Nurses' Health Study II aged 20-45 y, who had no cardiovascular disease, diabetes, or cancer. We prospectively evaluated the dietary intake of nuts and subsequent weight changes from 1991 to 1999. Results: Women who reported eating nuts 2 times/wk had slightly less mean (6 SE) weight gain (5.04 6 0.12 kg) than did women who rarely ate nuts (5.55 6 0.04 kg) (P for trend , 0.001). For the same comparison, when total nut consumption was subdivided into peanuts and tree nuts, the results were similar (ie, less weight gain in women eating either peanuts or tree nuts 2 times/wk). The results were similar in normal-weight, overweight, and obese participants. In multivariate analyses in which lifestyle and other dietary factors were controlled for, we found that greater nut consumption (2 times/wk compared with never/almost never) was associated with a slightly lower risk of obesity (hazard ratio: 0.77; 95% CI: 0.57, 1.02; P for trend ¼ 0.003). Conclusions: Higher nut consumption was not associated with greater body weight gain during 8 y of follow-up in healthy middleaged women. Instead, it was associated with a slightly lower risk of weight gain and obesity. The results of this study suggest that incorporating nuts into diets does not lead to greater weight gain and may help weight control.