Proteinuria in Mexican Americans and non-Hispanic Whites with NIDDM

Mexican Americans have a threefold greater prevalence of non-insulin-dependent diabetes mellitus (NIDDM) than non-Hispanic Whites as found in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. In addition, Mexican-American diabetic subjects have higher levels of glycemia than non-Hispanic White diabetic subjects. We therefore hypothesized that the prevalence of clinical proteinuria would be greater among Mexican-American diabetic subjects (n = 317) than among non-Hispanic White diabetic subjects (n = 67). Clinical proteinuria, defined as ≥1+ on the Ames Albustix test, was 2.82 times more prevalent in Mexican-American diabetic subjects compared with non-Hispanic White diabetic subjects adjusting for age and duration (95% confidence interval [CI] = 1.05, 7.55; P = .039). After controlling for other possible confounding variables (i.e., glycemia, systolic blood pressure, smoking, and insulin use), the excess of proteinuria in Mexican-American diabetic subjects was only slightly attenuated, although the statistical significance became borderline (odds ratio [OR] = 2.59, 95% CI = 0.91, 7.32; P = .072). The prevalence of microalbuminuria (>30 mg/L) was also significantly higher in Mexican-American diabetic subjects than in non-Hispanic White diabetic subjects (OR = 3.54, 95% CI = 1.28, 9.81; P = 0.15). We also compared previously diagnosed Mexican-American diabetic subjects (n = 243) from San Antonio with previously diagnosed non-Hispanic White diabetic subjects in Wisconsin (n = 476). After controlling for age and duration of diabetes, Mexican-American diabetic subjects had a significantly higher prevalence of clinical proteinuria than the Wisconsin diabetic subjects (Mantel-Haenszel OR = 1.58, 95% CI = 1.05, 2.40; P = .017). Our data indicate that Mexican-American diabetic subjects have a higher prevalence of clinical proteinuria and microalbuminuria than non-Hispanic White diabetic subjects.