Lung function indices of obese secondary school adolescents in Port Harcourt, Nigeria

Background: Obesity is associated with increased risk of respiratory symptoms, morbidity and mortality. There is a dearth of literature on the effect of obesity on lung functions among the adolescent age group. Objective: The aim of this study was to determine the effect of obesity on lung function test indices among obese secondary school adolescents. Methods: It was a descriptive analytical study carried out from May to July 2019. A multi-stage sampling technique was used to recur it adolescents from 16 secondary schools in Port Harcourt Local Government Area, Rivers State. Data were collected using a structured interviewer administered questionnaire. Weight and height were measured using a digital weighing scale and a stadiometer respectively. Body mass index was calculated as weight (kg)/height2 (m2) with WHO Anthro-Plus software and categorized using WHO standard BMI-for-age Z-score charts for boys and girls 5 to 19yrs. Lung function indices were measured using a digital hand-held Spiro bank II spirometer which was calibrated based on the GLI 2012 equation. Results: A total of 224 secondary school adolescents were recruited for the study out of which 108 (48.21%) were males and 116 (51.79%) were females, giving a M: F ratio of 0.93:1. Before controlling for confounders, obese females had significantly low mean percentage predictive values of FEV1 and PEF compared to normal (FEV1: 72.2 vs. 82.83; PEF: 67.73 vs. 71.7; p=0.011).After correcting for confounders (socioeconomic status and parental smoking) using a regression model, obesity was significantly associated with lower FEV1 percentage predicted (p=0.010) and PEF percentage predicted (p=0.050). Among the obese adolescents, lung function indices correlated negatively with obesity severity, but was only statistically significant for FEV1 (r=-0.43, 95%CI: -0.15, -0.003; p=0.041)and PEF (r=-0.41, 95% CI: -0.20, 0.00; p=0.051). Conclusion: Obesity was associated with reduction in lung function indices; and obese subjects with higher body mass index had worse lung function test indices Therefore, it will be worthwhile to routinely carry out lung function tests as part of School Health Program, so that necessary measures and referrals would be implemented. On the other hand, this study exposed the need to put in place measures (such as playground in schools, discouraging fast-food patronage) to reduce the prevalence of obesity among secondary school adolescents in Port Harcourt.