MON-210 Role of Female Gender and Subcutaneous Fat in the Positive Association of Obesity with Idiopathic Hyperaldosteronism

Context: Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. The relationship between PA and various metabolic disorders including obesity, diabetes mellitus and dyslipidemia has been reported. On the other hand, PA consists of two main subtypes: unilateral aldosterone-producing adenoma (APA) and the bilateral idiopathic hyperaldosteronism (IHA), which have different etiologies. Recently, it was reported that the prevalence of obesity was higher in patients with IHA than those with APA, suggesting that there is a link between obesity and the etiology of IHA (Ohno Y et al. J Clin Endocrinol Metab 2018). Furthermore, it has also been reported that female patients with PA are more likely to have IHA than male patients. Objective: Our objective was to clarify the pathological role of female gender in the positive association of obesity with IHA. Because of the difference of body fat distribution between men and women, we also investigate the contribution of visceral and subcutaneous fats in the pathogenesis of IHA. Design: This retrospective observational study comprised 117 PA patients (IHA: n = 73, APA: n = 44) diagnosed by adrenal venous sampling between January 2006 and July 2019 at Jichi Medical University Hospital. We compared prevalence of obesity and metabolic parameters including visceral and subcutaneous fat areas measured by computed tomography between patients with IHA and APA by gender. We also compared visceral and subcutaneous fat areas between patients with IHA and APA by the presence of obesity, BMI ≥25 kg/m2 (the diagnosis criteria by Japan Society for the Study of Obesity). Results: In consistent with previous reports, BMI was significantly higher in patients with IHA than those with APA. However, in male patients, no difference of BMI between IHA and APA was observed. By contrast, in female patients, not only BMI but also both visceral and subcutaneous fat areas were significantly higher in IHA than in APA. Next, we investigated the contribution of visceral and subcutaneous fats in the positive association of obesity with IHA in female patients. Subcutaneous fat area but not visceral fat area was significantly higher in female obese patients with IHA. By contrast, visceral fat area but not subcutaneous fat area was significantly higher in female non-obese patients with IHA. Conclusions: These results suggest that obesity, especially subcutaneous fat accumulation, contributes to the pathogenesis of IHA in female patients.