0515 EFFECTS OF CONTINUOUS POSITIVE AIRWAY PRESSURE ON BODY COMPOSITION, PHYSICAL ACTIVITY, AND FOOD INTAKE IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA

Abstract

Introduction: Obstructive sleep apnea (OSA) may promote weight gain by affecting physical activity (PA), food intake, hunger/satiety hormones, and/or energy metabolism. We aimed to determine if continuous positive airway pressure (CPAP) alters behaviors involved in regulating body composition in individuals with OSA. Method(s): These are preliminary data from a prospective study of CPAP in obese OSA patients. To date, 9 individuals (n=3 females), age (+/- SEM) 48.1 +/- 4.1 y and apnea-hypopnea index 51.0 +/- 14.0 events/h, were studied. Outcomes were assessed at baseline and after 2 months of nightly CPAP use. Body composition measures included body mass index (BMI), and air displacement plethysmography (BodPod) for fat mass (FM) and fat-free mass (FFM). Free-living PA was recorded with wrist-actigraphy for 7 days. Food intake was assessed by providing participants with a stipend to purchase food items of their choice, and quantifying energy and macronutrient content of food consumed in the laboratory. Result(s): BMI slightly but significantly increased after CPAP (35.5 +/- 1.5 vs. 35.8 +/- 1.4, p=0.06). FM% decreased (39.4 +/- 2.4 vs. 38.1 +/- 2.4%; p=0.09), and FFM% increased (60.6 +/- 2.4% vs. 61.9 +/- 2.4%; p=0.09), corresponding with a significant increase in FFM (135.7 +/- 8.2 vs. 140.7 +/- 9.4 kg; p=0.02). Estimated resting metabolic rate (based on the Nelson Prediction Equation from FFM and FM obtained from the BodPod) increased after CPAP (1750.3 +/- 95.8 vs. 1787.2 +/- 102.7 kcal/d; p=0.06). Percent time in moderate-to-vigorous PA (MVPA) was significantly increased (3.2 +/- 0.7% vs. 5.6 +/- 1.1%, p=0.04). Percent time in sedentary and light PA were unchanged (p-values >=0.30). Actiwatch-derived average energy expended/hour increased (70.8 +/- 11.5 vs. 78.9 +/- 11.9 kcal/h; p=0.06). No differences were seen for food intake (energy and macronutrient), except for percent energy consumed as carbohydrate, which decreased after CPAP (55.0 +/- 2.4 vs. 48.7 +/- 1.5% p=0.04). Conclusion(s): Increased FFM appears to contribute to body weight gain after CPAP, and may be driven by increased levels of MVPA. Findings suggest that CPAP could be useful to encourage optimal cardiometabolic outcomes in OSA patients.