Effect of body mass index (BMI) on pulmonary functions in children of 6-14 years of age: A cross-sectional study.

Background: Over-weight/obesity is a new global pandemic affecting children with prevalence up to 36%. It is responsible for metabolic syndrome and its future complications in children; however, its effect on lung functions in children is not well studied.

Aim: To compare lung function tests [forced expiratory volume in the first second (FEV1), FEV1/forced vital capacity (FVC), FVC, and % predicted] of children with over-weight/obesity to that of normal children.

Method: it is a hospital-based cross-sectional study. Children of 6-14 years of age with over-weight [body mass index (BMI) >85 centile] and obesity (BMI >95 centile) attending the pediatrics outpatient department (OPD) were included. Age-matched children attending the OPD during the study period were selected as controls. Demographic and anthropometric details were collected, and pulmonary function tests were carried out in included children.

Results: A total of 103 children were included (over-weight/obese = 56, control = 47). The percent predicted (%) FEV1 (86.23 ± 12.84 vs 91.77 ± 8.68) and FVC (81.93 ± 12.12 vs 88.62 ± 10.87) were significantly lower in the obese/over-weight group as compared to control group. A signification negative correlation was found between FEV1 (%) and FVC (%) and that of BMI and waist-hip ratio (WHR).

Conclusions: Pulmonary functions (FEV1, FVC) are found to be negatively correlated with BMI and WHR.