Lower hypertension risk in Mexico City than in San Antonio

Background We examined the effects of blood pressure (BP), weight, and weight gain on hypertension risk in two similar ethnic origin populations, subjects in Mexico City and Mexican Americans in San Antonio. Methods The Mexico City Diabetes Study and San Antonio Heart Study are population-based, epidemiologic studies with identical survey protocols. Incident hypertension (BP ≥140/90 mm Hg or current antihypertensive treatment) was analyzed in subjects aged 35 to 64 years of Mexican ethnicity living in low-income neighborhoods (n = 1467 in Mexico City, n = 628 in San Antonio). Results In Mexico City, 10.6% of men and 13.1% of women developed hypertension in a 6.5-year period; in San Antonio, 28.6% and 28.7% in a 7.5-year period, respectively. Poisson regression analysis demonstrated a greater hypertension risk in San Antonio for both men (risk ratio [RR] = 1.75, 95% confidence interval [CI]: 1.19–2.56) and women (RR = 1.40, 95% CI: 1.05–1.86). In a multiple linear regression analysis, systolic BP change was associated with weight gain in Mexico City (P< .001 in men and women) and San Antonio (P = .045 in men, and P = .027 in women) independently of age, BP, obesity, alcohol consumption, cigarette smoking, diabetes, and antihypertensive treatment. These covariates did not fully explain greater increments of systolic BP in San Antonio than in Mexico City (P< .001 in men and women). Conclusions Hypertension risk is lower in Mexico City than in San Antonio. Systolic BP increases with weight gain, independently of other determinants of hypertension.