<b>Introduction:</b> There are few studies evaluating the effect of weight loss as a treatment for obstructive sleep apnea (OSAS) in obese children. <b>Aims:</b> To evaluate the effect of weight loss as a treatment for mild OSAS among obese children recruited from the community. <b>Methods:</b> A prospective, multicenter study of Spanish children ages 3–14 years-old with a body mass index (BMI)≥95th percentile for age and sex, who were diagnosed with mild OSAS (Alonso-Álvarez ML et al. <i>SLEEP</i> 2014;37(5):943-9), and who were subsequently managed with a standard dietary intervention. Polysomnography, nasopharyngoscopy and anthropometry were performed at baseline and follow-up. Diagnosis of OSAS was established using a respiratory disturbance index (RDI)≥3/hrTST. <b>Results:</b> 36 obese children with mild OSAS at baseline completed the initial (T0) and follow-up (T1) assessments. 50% of them had an RDI ≥3 /hrTST at T1 (persistent cases) and 50% of them had an RDI < 3 at T1 (Remission Cases). In the remission cases, the mean RDI at T0 and T1 was 5.97±2.19 and 1.71±0.89 respectively. In the persistent cases, the mean RDI at T0 and T1 was 11.18±6.29 and 7.69±5.47 respectively. A general linear model approach was used, the BMI in the remission cases decreased, while BMI increased in the group with persistent OSAS (BMI from T0 to T1: - 0.33±2.83 and 0.36±2.05/kg.m2, respectively). A statistically significant association between BMI change from T0 to T1 and parallel RDI changes emerged (r=0.362, p=0.03). <b>Conclusions:</b> BMI reduction is associated with improvements in polysomnographic parameters among obese children with OSAS. However, persistence of OSAS occurs in a high percentage of cases. Funded by SEPAR.
