Association of body weight on pulmonary function tests in young individuals (aged 18- 40 years)- A cross-sectional study

This was a prospective cross-sectional study conducted to evaluate association of waist, hip and thigh circumferences on respiratory parameters among young healthy adults. A total of 180 volunteers of different weight categories; including underweight, normal weight, over weight and obese people were recruited by using non-probability convenient sampling technique. Non-smoker males and females (non-pregnant), aged between 18-40 years with no pulmonary and cardiac disease were included in the study. Waist circumference, mid-thigh circumference, hip circumference and respiratory parameters were measured. The results showed a  significant association between waist circumference with forced vital capacity (FVC) (r = 0.188, p = 0.011), average tidal volume (VT) (r = 0.160, p = 0.032), inspiratory reserve volume (IRV) (r = 0.388,p<0.001), vital capacity (VC) (r = 0.312, p<0.001), total lung capacity (TLC) (r = 0.385, p<0.001), and functional residual capacity (FRC) (r = 0.477, p<0.01),  and a negative association with forced expiratory volume in 1 second (FEV1) (r = -0.148, p = 0.048) and FEV1/FVC ratio (r = -0.246, p<0.001). Significant association was not observed between waist circumference and expiratory reserve volume (ERV) (r = 0.071, p = 0.344).  In the present study, increased waist, hip, and thigh circumferences were found to be negatively associated with FEV1 and FEV1/FVC ratio. Spirometry should be performed in obese and overweight young healthy adults even if they are asymptomatic, as early preventive measures can be taken to reduce the resulting morbidity.