Predictors of visceral obesity in normal weight obstructive sleep apnea patients

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is epidemiologically related to adverse cardiovascular outcomes. The pathophysiology clues are metabolic changes and obesity. The most studied anthropometric predictors of obesity, such as body mass index (BMI), waist circumference (WC), are influenced by various factors such as sex, type of constitution, hydration balance. The normal range of BMI and WC limits the diagnostic search for metabolic disturbances and visceral obesity in patients with respiratory sleep distress and can lead to increased cardiovascular risks. AIMS: to investigate the visceral obesity predictors in normal weight patients with obstructive sleep apnea syndrome. MATERIALS AND METHODS: We had performed а cross-sectional study, 68 patients were examined with mean age of 38.24 ± 7.4 years. The main group (38 individuals) was represented by patients with OSAS. The control group consisted of healthy individuals without OSAS. Alternative markers of visceral obesity, such as lipid accumulation products, visceral obesity index, conicity index have been studied. RESULTS: In the main group we found different disorders of lipid metabolism such as the increase in triglyceride levels by 94%, low-density lipids by 32%, total cholesterol by 10% compared with the control group. Anthropometric evidence was obtained for excessive fat accumulation in patients with normal body weight and OSAS: WC was 89.6 ± 5.7 cm in the main group and was higher than in the control group 83.7 ± 6.3 cm (p = 0.024) due to an increase in the visceral fat compartment, as evidenced by the conicity index (67.2 ± 7.0 and 59.3 ± 6.2 respectively, p = 0.032) and waist to height ratio (0.58 ± 0.05 and 0.53 ± 0.04 in the main and control groups, respectively, p = 0.041). Correlation relationships between the severity of sleep apnea syndrome and visceral obesity indicators were revealed. CONCLUSIONS: Normal weight patients with breathing disorders are at risk of visceral fat obesity and, thereby, increased cardiovascular risk. Assessment of additional markers of visceral obesity in patients with normal body weight and sleep apnea is recommended to include in the dynamic observation programms.