Characterization of the Renin-Angiotensin-Aldosterone System in Young Healthy Black Adults: The African Prospective Study on the Early Detection and Identification of Hypertension and Cardiovascular Disease (African-PREDICT Study)

Abstract

This study presents a detailed profile of the renin-angiotensin-aldosterone system (RAAS), electrolytes, volume loading, blood pressure (BP), and total peripheral resistance in healthy young Black and White adults. We also explored longitudinal associations between BP and RAAS. We included normotensive Black (N=543) and White (N=573) adults (20–30 years) and followed N=324 over ≈4.5 years. We measured clinic (central, brachial) and 24-hour BP, total peripheral resistance and left ventricular dimensions. We determined serum NT-proBNP (N-terminal prohormone B-type natriuretic peptide), RAAS, and 24-hour urinary and serum Na + and K + . RAAS components, left ventricular internal diameter (diastole), end diastolic volume and NT-proBNP were lower ( P <0.001) in Black than White adults, despite similar clinic SBP. However, central systolic BP and total peripheral resistance were higher in Black adults ( P <0.001). Plasma renin activity and angiotensin II were comparable between Black and White groups ( P >0.05) only in quartile 1 of Na + /K + values. In both groups, RAAS was lower in the higher quartiles of 24-hour Na + and NT-proBNP (all P -trend≤0.014). Over 4.5 years, all BPs increased in the Black ( P <0.001) but not White group. The increase in central systolic BP over time was associated with elevated serum aldosterone only in Black adults (β=0.18, P =0.038). We found that RAAS concentrations in healthy Black adults were half of those of White participants, which may not be explained by volume expansion. Yet, baseline aldosterone predicted BP elevation over time in Black adults. RAAS was similar in Black and White adults only at low Na + /K + scenarios, suggesting an essential role of potassium. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03292094.

Soluble (Pro)renin Receptor Is Adversely Associated with Indices of Left Ventricular Structure and Function: The African-PREDICT Study

“…Our study included apparently healthy black ( n = 587) and white ( n = 585) men and women with a comparable sex distribution and confirmed the influence of ethnicity on s(P)RR levels. As previously reported in this cohort [ 19 ], PRA-s, a measure of renin activity and eq AngII were two-fold higher in white participants as compared to black participants. Prorenin was higher in white participants which is inconsistent with recent relevant studies [ 18 , 41 ].…”

“…Independent sample t-tests were used to compare black and white participants. Ethnicity-pooled and ethnicity-specific regression analyses were performed to account for the well-known ethnic heterogeneity in RAS activity [ 19 , 25 ]. Candidate independent variables included age, ethnicity (in ethnicity-pooled analysis), sex, waist circumference, socioeconomic score, 24 h diastolic blood pressure, eGFR, Na + /K + , glucose, LDL-c, CRP, smoking, alcohol use and AEE as independent variables.…”

“…For the s(P)RR comparison, the study included a small sample of black and white participants, highlighting the need for further studies in human populations to confirm the ethnic differences in s(P)RR. Ethnic differences are important when investigating RAS due to the known lower levels of classical RAS components in black populations as compared to their white counterparts, and the impact on response to some classes of antihypertensive drugs [ 19 , 20 , 21 ].…”

Blood Pressure and Stroke: A Review of Sex- and Ethnic/Racial-Specific Attributes to the Epidemiology, Pathophysiology, and Management of Raised Blood Pressure

“…209 Blacks tend to have a suppressed renin-angiotensin-aldosterone system activity, including low renin status and accordingly, low renin hypertension is common. 210,211 Other hypothesized etiology for more prevalent hypertension among Blacks include sodium abnormalities, epithelial sodium channel changes, altered genes regulating the renin-angiotensin-aldosterone system, increased peripheral vascular resistance, increasing obesity, early vascular aging (large artery stiffness), and underweight phenotype. 120,210 East Asians have a genetically higher salt sensitivity.…”

Population‐based discovery and Mendelian randomization analysis identify telmisartan as a candidate medicine for Alzheimer's disease in African Americans

“…A large genetic study has shown that renal development is significantly mediated by AD‐associated loci in the AAs, compared to the non‐Hispanic EAs 16 . Furthermore, the renin‐angiotensin‐aldosterone system (RAAS) is markedly less robust in healthy young AA adults than in their EA counterparts 17 . Specifically, AA adults have a greater aldosterone sensitivity than EA adults 18 .…”