Independent Association of Serum Aldosterone Level with Metabolic Syndrome and Insulin Resistance in Korean Adults

Background and Objectives: A relationship between renin-angiotensin system (RAS) components and metabolic syndrome (MetS) has been suggested, but not elucidated clearly. We examined the levels of RAS components in patients with and without MetS and their association with MetS in Korean population. Methods: This study was approved by the review boards of the participating institutions and endorsed by the Korean Society of Lipid and Atherosclerosis. We screened 892 Koreans aged ${\geq}20years$ who underwent evaluation of hypertension, diabetes, or dyslipidemia at 6 tertiary hospitals in 2015-2016. After excluding patients who were taking diuretics, ${\beta}-blockers$, or RAS blockers, or suspected of primary aldosteronism, 829 individuals were enrolled. Anthropometric and biochemical parameters including aldosterone, plasma renin activity (PRA), and aldosterone-to-PRA ratio were evaluated. The homeostasis model assessment for insulin resistance (HOMA-IR) were used for evaluating insulin resistance. Results: The mean age of the participants was $52.8{\pm}12.8years$, 56.3% were male, and their mean systolic and diastolic blood pressures were $133.9{\pm}20.0$ and $81.2{\pm}14.6mmHg$, respectively. The levels of serum aldosterone, but not PRA, were significantly higher in subjects with MetS than in those without ($20.6{\pm}33.6$ vs. $15.3{\pm}12.2ng/dL$, p<0.05), and positively correlated with waist circumference, blood pressure, triglycerides, and glycated hemoglobin. The levels of aldosterone were independently associated with the number of MetS components and HOMA-IR after adjusting for conventional risk factors. Conclusion: Serum aldosterone levels were higher in Korean adults with MetS than in those without. This finding suggests that increased aldosterone level might be closely associated with insulin resistance.