A CROSS-SECTIONAL STUDY TO DETERMINE THE EFFECT OF OBESITY ON PULMONARY FUNCTION TESTS USING “BODY BOX PLETHYSMOGRAPHY”

Introduction: As compared to healthy weight subjects, obese individuals are more susceptible to respiratory infections and obese patients with respiratory disease have higher hospitalization rates. This cross-sectional study was conducted to observe the effect of obesity on pulmonary function tests in otherwise healthy adults. Materials and Methods: Study comprised of 180 subjects in the age group of 18-65 years divided into 3 groups: Group I comprising 60 normal subjects with body mass index (BMI) between 18.5-24.9 Kg/m², Group II comprising 60 overweight subjects with BMI between 25-29.9 Kg/m², and, Group III comprising 60 obese subjects with BMI ≥ 30 Kg/m². It was carried out in Department of Physiology, Government Medical College, Patiala from December 2020 to November 2022. The pulmonary function tests were recorded by spirometry using body box plethysmograph. Results: All respiratory parameters exhibited statistically significant decrease in obese groups as compared to normal and overweight groups. Lung volumes showed significant differences in relation to BMI. FVC, FEV₁ and FEV₃ showed significant decrease in relation to BMI with Group III (obese) as compared to Group I (normal) and Group II (overweight) with p<0.01 in both cases. FEV₁/FVC showed a significant increase in obese (91.25 ± 6.08) as compared to normal (86.83 ± 7.7) and overweight (86.03 ± 6.9) groups. Conclusion: Obesity of especially marked degrees with BMI of more than 30 kg/m² alters the respiratory physiology and negatively affects the spirometric parameters. Restrictive pattern was the most common abnormality observed in the spirometry of obese patients.