8-YEAR INCIDENCE OF HYPERTENSION IN MEXICAN-AMERICANS AND NON-HISPANIC WHITES - THE SAN-ANTONIO HEART-STUDY

The prevalence of hypertension has been reported to be lower in Mexican-Americans (MAs) than in non-Hispanic whites (NHWs). This finding is paradoxical since, compared to NHWs, MAs are generally more obese, and generally have a higher prevalence of non-insulin-dependent diabetes mellitus (NIDDM), both of which are risk factors for hypertension. Thus far, no data exist on the incidence of hypertension in MAs. We therefore determined the 8-year incidence of hypertension (defined as a diastolic blood pressure greater-than-or-equal-to 95 mm Hg or current treatment with antihypertensive medications) in 1462 subjects (867 MAs and 595 NHWs) who were normotensive at baseline and who subsequently participated in the 8-year follow-up of the San Antonio Heart Study, a population-based study of diabetes and cardiovascular risk factors. Hypertension developed in 79 MAs (9.1%) and 55 NHWs (9.2%). The age-adjusted odds ratio (OR) for ethnicity (MA/NHW) was 0.83 (95% CI = 0.48, 1.44) in men and 1.25 (95% CI = 0.76, 2.04) in women. After adjusting for age, gender, body mass index, NIDDM, and level of educational attainment using multiple logistic regression, Mexican-Americans had an incidence of hypertension similar to non-Hispanic white (OR = 0.80, 95% CI = 0.52, 1.22). The similar incidence of hypertension in MAs is in striking contrast to the markedly increased incidence of NIDDM in this ethnic group relative to non-Hispanic whites. The cause of the relative protection from hypertension in MAs is unknown.