Effects of a One-Year Intensified Weight Loss Program on Body Composition Parameters in Patients with Severe Obesity and Obstructive Sleep Apnea (OSA): A Randomized Controlled Trial

<b>Background:</b> Studies focusing on the effects of lifestyle strategies on patients with obstructive sleep apnea (OSA) that go beyond body weight and explore body composition are currently scarce and inconclusive. <b>Objectives/Methods:</b> The aim of this study was to evaluate the effects of a 12-month intensive life intervention program (ILI), based on a hypocaloric Mediterranean diet, on changes in the body composition parameters as assessed by abdominal computed tomography (CT) and the cardiorespiratory profile of patients with severe OSA and grade I-II obesity, compared to patients receiving standard care. Resultts:Thirty-four patients (30 males and four females) were randomly assigned to an intervention group (IG) (<i>n</i> = 18) or a control group (CG) (n = 16). We observed an improvement in OSA severity following the intervention. Patients in the IG lost 8.2% of their body weight compared to 0.1% of the patients in the CG (<i>p</i> < 0.001), and this loss was primarily due to reductions in total body fat, visceral adipose tissue index (VATI) [IG -19.4 (18.1) cm²/m² versus CG 2.32 (11.6) cm²/m², <i>p</i> < 0.001], and a tendency toward lower intramuscular adipose tissue index (IMATI) [IG -0.69 (0.85) cm²/m² versus CG 0.04 (1.3) cm²/m², <i>p</i> = 0.098]. These changes were associated with an improvement in patients' metabolic and inflammatory profile. Younger age and a higher degree of obesity at baseline were associated with greater weight loss. Conslusions: In conclusion, the ILI was effective in reducing 8.2% of body weight at 12 months, leading to favorable changes in patients' body composition profile that resulted in healthier metabolic and inflammatory parameters.