Association of Renin and Aldosterone With Ethnicity and Blood Pressure: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND Although variations in plasma renin activity (PRA) and aldosterone have been examined in whites and blacks, the association of these hormones with blood pressure in multiethnic populations has not been described. METHODS We measured PRA and aldosterone in 1,021 participants in the Multi-Ethnic Study of Atherosclerosis not taking antihypertensives and examined the association between ethnicity and PRA/aldosterone and the association between PRA/aldosterone with systolic blood pressure (SBP). RESULTS Average age was 62 (SD = 9) years, and 49% of participants were women. Median PRA was 0.51 (interquartile range (IQR) = 0.29-0.87) ng/ml/hour, and median aldosterone was 12.6 (IQR = 9.1-17.1) ng/dl. After age and sex adjustment, compared with whites, blacks had 28% lower PRA and 17.4% lower aldosterone, and Hispanics had 20.1% higher PRA but similar aldosterone levels. After multivariable adjustment, compared with whites, only Hispanic ethnicity independently associated with higher PRA (0.18 ng/ml/hour; 95% confidence interval (CI) = 0.06-0.31). Blacks had lower aldosterone (-1.7 ng/dl; 95% CI = - 3.2 to - 0.2)compared with whites. After multivariable adjustment, PRA was associated with lower SBP in whites (- 3.2 mm Hg; 95% CI = -5.2 to -1.2 per standardized unit PRA), Chinese (-3.5 mm Hg; 95% CI = -6.2 to -0.80 per standardized unit), and Hispanics (-2.3 mm Hg; 95% CI = -4.1 to -0.6 per standardized unit) but not blacks. Aldosterone was associated with higher SBP only in Hispanics (2.5 mm Hg; 95% CI = 0.4-4.5 per SD). CONCLUSIONS Compared with whites, blacks have lower aldosterone and Hispanics have higher PRA. Aldosterone had significant associations with higher SBP in Hispanics compared with other groups, a finding that may suggest a different mechanism of hypertension.