Assessment of pulmonary functions in obese adolescent boys

Abstract

Background: Obesity is rapidly escalating in India in all age groups. School-based data indicate a prevalence rate between 5.6% and 24% in children and adolescents. Adolescent obesity is associated with a greater long-term risk of hypertension and type 2 diabetes mellitus in adulthood. However, studies investigating pulmonary functions in obese adolescents are few. The present study assesses pulmonary functions in obese adolescent boys from a school in Baroda city, Gujarat.

Aims: (i) To assess the dynamic lung functions in obese adolescent boys. (ii) To determine the predominant lung function impairment associated with obesity in adolescence.

Materials and methods: Dynamic lung functions were measured in 30 obese adolescent boys and an equal number of age-matched controls using MEDI:SPIRO software (Maestros Mediline Systems Ltd., Navi Mumbai, India).

Results: Forced expiratory volume in the 1(st) second (FEV(1))/forced vital capacity (FVC) and maximum voluntary ventilation (MVV) were significantly decreased in the obese group (P < 0.001). Pulmonary functions in the study population correlated negatively with various indices of obesity, viz. weight, body mass index (BMI), waist circumference, hip circumference, and waist-to-hip ratio. The strongest negative correlation was between BMI and FEV(1)/FVC (P < 0.001) and between BMI, MVV, and Forced Expiratory Flow (FEF(25-75%)) (P < 0.001). Waist-to-hip ratio in the study population correlated negatively with MVV (P < 0.01), but not with FEV(1)/FVC.

Conclusions: Lung function impairment, particularly decreased MVV and reduced FEV(1)/FVC ratio, is associated with obesity in adolescence. In addition, pulmonary functions deteriorate with increasing obesity in adolescence and correlate negatively with various indices of obesity, viz. weight, BMI, waist circumference, hip circumference, and waist-to-hip ratio. This study reveals another health hazard associated with obesity and highlights the need to aggressively reduce weight at a younger age.

Keywords: Adolescent obesity; body mass index; pulmonary function tests; waist-to-hip ratio.

Figure 1

Comparison of FVC and FEV₁ (% of predicted values) of the control and obese groups

Figure 2

Comparison of PEFR and FEF_25–75% (observed values) of the control and obese groups

Figure 3

Comparison of the pulmonary function parameters (observed values) of the control and obese groups

Figure 4

Correlation between BMI and FEV₁/FVC in the entire study population (N = 60)

Figure 5

Correlation between BMI and MVV in the entire study population (N = 60)

Figure 6

Correlation between waist/hip ratio and MVV in the entire study population (N = 60)