The prevalence of non-insulin-dependent diabetes mellitus (NIDDM) is higher in Mexican Americans than in non-Hispanic white Americans, even after adjustment for the former's greater overall and more centralized adiposity. We postulated that this excess risk of NIDDM could be due to resistance to insulin. We performed oral glucose-tolerance tests with measurements of serum insulin concentrations in 225 Mexican Americans and 180 non-Hispanic whites without diabetes as part of the San Antonio Heart Study, a population-based study of risk factors for diabetes. Changes in serum insulin concentrations in response to the glucose challenge were quantified by the area under the serum insulin curve. Overall adiposity was characterized by body-mass index, and regional body-fat distribution by the ratio of subscapular to triceps skinfolds and the ratio of waist to hip circumference. After adjustment for these indicators of adiposity and also for differences in glucose tolerance, Mexican Americans were found to have significantly greater areas under the serum insulin curve than non-Hispanic whites. These data suggest that, like other populations at high risk for NIDDM such as Pima Indians and Micronesians, Mexican Americans have more hyperinsulinemia than can be accounted for by their adiposity.

Recent reports suggest that coffee consumption is associated with increased serum cholesterol and triglyceride concentrations. The authors examined the association between serum lipids and coffee consumption and other caffeinated beverages as part of a population-based study of 1,228 women and 923 men, aged 25-64 years, in San Antonio, Texas, studied between October 1979 and November 1982. The study confirmed a positive relationship between coffee consumption and both total and low density lipoprotein cholesterol in both sexes which persisted after adjustment for age, ethnicity, obesity, cigarette smoking, and alcohol consumption. Neither tea nor cola consumption was associated with changes in serum lipids, suggesting that caffeine alone does not exert a direct effect on lipid levels. The possibility was examined that the coffee-cholesterol relationship might be due to a more atherogenic diet consumed by heavy coffee drinkers. In men, per cent calories from both total and saturated fat and dietary cholesterol intake increased with increased coffee consumption. Similar trends were not observed in women, however. The positive relationship between coffee and cholesterol may therefore be due to confounding effects of other aspects of the diet.