The Relationship Between the Aldosterone-to-Renin Ratio and Blood Pressure in Young Adults: A Longitudinal Study

Background: Hypertension tracks throughout childhood into adulthood. Aldosterone excess, or primary aldosteronism, has been reported as the most common secondary cause of hypertension in adults. Elevated aldosterone in the setting of low renin predicts incident hypertension in normotensive adults. However, the relationship between aldosterone and blood pressure in adolescents and young adults is unclear. Objectives: To evaluate the relationship between aldosterone, renin and the aldosterone:renin ratio (ARR) and blood pressure (BP) at age 17y as well as BP at age 27y in a community-based population. Methods: This is a prospective birth cohort study. Young adult offspring (Gen2) of women enrolled during pregnancy into the Raine Study, with 1239 at age 17y and 1006 at age 27y, were evaluated. Females taking hormonal contraception and participants without BP data were excluded from the current analysis. A generalised linear model was used to examine the relationship between BP and aldosterone, renin and ARR over time. The median aldosterone, renin and ARR was compared between sexes using quantile regression. Results: At 17y, females had similar aldosterone (349 vs 346 pmol/L, p=0.833) but significantly lower renin (20.6 vs 25.7 mU/L, p<0.001) and thus a higher ARR (18.3 vs 13.5, p<0.001) compared to males. However, they had lower systolic BP (109 vs 118 mmHg, p< 0.001) versus males. A significant correlation between ARR and systolic BP was detected in 17y males when adjusted for alcohol consumption, physical activity, urinary sodium and body mass index. This was true when the ARR was expressed as a continuous variable (β-coefficient 0.1, p=0.009) or categorical variable (highest quartile, β-coefficient 3.15, p=0.003). A similar correlation was not observed in females at 17y. However, the ARR at 17y was significantly associated with both systolic (β-coefficient 0.15, p=0.009) and diastolic BP (β-coefficient 0.14, p=0.003) at 27y in females, but not males. Conclusion: A relationship between ARR and BP are observed at both 17 and 27 years but with distinct age-related sex differences. Further evaluation of the relationship between ARR and surrogate markers of cardiovascular disease such as vascular reactivity will improve our understanding of aldosterone as a cardiovascular risk factor young people.