Limkul L.Udomittipong K.Charoensittisup P.Mahoran K.Mahidol University2025-09-142025-09-142025-09-01European Journal of Pediatrics Vol.184 No.9 (2025)03406199https://repository.li.mahidol.ac.th/handle/123456789/112050Obesity is a pervasive global health issue frequently associated with metabolic syndrome (MetS). Limited data exist regarding the impact of MetS and its individual components on pulmonary function in obese pediatric populations. This study investigated the relationship between MetS and lung function, and further identified specific MetS components that adversely affect pulmonary outcomes. We enrolled obese children and adolescents aged 7‒18 years. Anthropometric measurements and metabolic assessments were performed. All participants underwent spirometry and the six-minute walk test (6-MWT). Based on MetS criteria, participants were classified into MetS or non-MetS groups. Between-group comparisons were conducted, and regression analyses were used to identify MetS components predictive of lung function and exercise capacity. A total of 155 participants were evaluated (37 [23.9%] with MetS; 118 [76.1%] without). Those with MetS demonstrated a significantly lower 6-MWT distance z-score (‒0.61 ± 1.1 vs ‒0.07 ± 0.99; P = 0.006). No significant group differences were found in spirometric parameters. Obesity indices exerted a stronger negative effect on lung function than MetS status. Abdominal circumference (b = ‒0.03, P < 0.001) and elevated FBS (> 100 mg/dL; b = ‒0.50, P = 0.04) were associated with reduced 6-MWT distance z-scores; they also negatively influenced FEV1% predicted (abdominal circumference: b = ‒0.15, P < 0.04; elevated FBS: b = ‒9.04, P = 0.02). Conclusions: Obese children and adolescents with MetS show significantly diminished functional capacity as evidenced by lower 6-MWT performance. Among MetS components, increased abdominal circumference and elevated FBS (> 100 mg/dL) emerged as critical predictors of decreased functional capacity. (Table presented.)MedicineArticleSCOPUS10.1007/s00431-025-06446-52-s2.0-10501517865714321076