Factors correlated with plasma renin activity in general Japanese population

Background: The renin-angiotensin-aldosterone system plays a pivotal role in regulation of blood pressure and electrolyte homeostasis and is a target in the treatment of hypertension and renal diseases. However, the factors correlated with plasma renin activity (PRA) are unclarified in general Japanese population. To examine this point, we conducted a community-based cross-sectional study. Methods: Subjects of this study were 2,056 individuals (mean age, 61 years; 934 men; 1,122 women) over 40-year-old without antihypertensive medication in Takahata town, Japan. PRA was measured by radioimmunoassay. Estimated 24-h urine sodium (e24hUNa) and potassium excretion were calculated from morning spot urine. Results: The median value of PRA was higher in men compared to women (1.1 ng/ml/h vs. 0.7 ng/ml/h, P < 0.001). The increased PRA (>2.0 ng/ml/h) were detected in 248 men (26.3%) and 142 women (12.7%). One-factor analysis of variance showed that PRA was correlated with blood pressure, uric acid, hemoglobin, total protein, total cholesterol, low-density lipoprotein cholesterol, serum adiponectin and e24hUNa in men. In women, PRA was correlated with age, blood pressure, total protein, high-density lipoprotein cholesterol (HDL-C), serum insulin, e24hUNa and obesity. Multivariate logistic regression analysis showed that high PRA (>2.0 ng/ml/h) was independently associated with low blood pressures, low e24UNa and high serum total protein both in men and women, smoking only in men and high HDL-C only in women, respectively. Conclusions: This study revealed that PRA was higher in men than women and was associated negatively with blood pressures and urine sodium excretion, and positively with total protein, smoking and HDL-C in Japanese population.