Rapid decrease of resting energy expenditure after a three-months lifestyle intervention in osas patients.

The objective of this study was to estimate basal energy expenditure and variation in anthropometrics and body composition parameters after dietetic and lifestyle treatment in a population of obese untreated obstructive sleep apnea syndrome (OSAS) patients. Patients and methods: Sixteen obese mild to moderate untreated OSAS patients (AHI 5-29) followed a program of dietetic lifestyle and weight management. Body composition, anthropometric measures, indirect calorimetry, blood analysis, and results of the questionnaire for the Stanford Sleepiness Scale (SSS) were recorded with follow-up at 3 months. Results: Eleven patients completed the study. Weight (p = 0.001), body mass index (BMI) (p = 0.001), neck circumference (p = 0.003), fat mass (FM) (p = 0.036), and resting metabolic rate (RMR) (p = 0.008) also in connection with FM (p = 0.008) showed meaningful associations. Multivariate associations between weight and neck circumference (p = 0.025), weight and SSS score (p = 0.001), and RMR and FFM loss (p = 0.019) were also noted. Respiratory quotient was unvaried. Conclusion: The results of our study, in agreement with those of other works, confirm the importance of weight decrease for OSAS therapy. A significant association between weight loss and symptomatology estimated with SSS was observed, mainly in relation to the circumference of the neck. These data confirm the hypothesis that one of the main pathogenetic factors of nocturnal apneas in obese patients is the deposition of adipose tissue around the upper airway. The massive reduction in RMR was one of the reasons management of weight loss in OSAS patients is complicated. Why RMR decrease is not related to a decrease of FFM and possible alterations of lipid metabolism in OSAS patients should be analyzed further in other studies. © SINPE-GASAPE.