Association Between Pituitary-Adrenal Axis Dominance Over the Renin-Angiotensin-Aldosterone System and Hypertension

CONTEXT: The hypothalamus-pituitary-adrenal (HPA) axis and the renin-angiotensin aldosterone system (RAAS) are well known to be associated with hypertension. However, the extent of the effects is not yet well elucidated in general conditions. OBJECTIVE: To separately determine the effect of the HPA axis and the RAAS on hypertension in a general population. DESIGN, SETTING, AND PARTICIPANTS: A population-based study of 859 Japanese individuals enrolled in the 2014 Iwaki study and without hypertension or steroid treatment (age, 50.2 ± 14.7 years). MAIN OUTCOME MEASURES: Hypertension prevalence, plasma concentration of aldosterone, ACTH, cortisol, and plasma renin activity. RESULTS: Principal component (PC) analysis using these four hormones identified two PCs (PC1 and PC2), which represent levels of these hormones as a whole, and dominance between the HPA axis (ACTH and cortisol) and the RAAS (plasma renin activity and plasma concentration of aldosterone), respectively. Association between these PCs and hypertension was significant (PC1, high vs low, odds ratio [OR], 1.48; 95% confidence interval [CI], 1.09-2.02; and PC2, HPA axis vs RAAS dominancy, OR, 2.08; and 95% CI, 1.51-2.85). However, association between the hormone levels as a whole and hypertension became insignificant after adjustment for multiple factors including these PCs together. However, association between the HPA axis dominance and hypertension remained significant even after the adjustment (the HPA axis vs the RAAS, OR, 1.73; 95% CI, 1.20-2.48). CONCLUSIONS: The HPA axis dominance over the RAAS is significantly associated with hypertension in a Japanese population.