ABSTRACT
Objective To investigate the relationship between underweight and pulmonary function in the general population. Methods A total of 2 350 patients who underwent a pulmonary function examination at Chongqing Three Gorges Central Hospital from January to June 2019 were selected as the study subjects. The subjects were divided into three groups based on their BMI value including underweight (2), normal weight (BMI between 18.5 kg/m2 and 25 kg/m2), and overweight and obese (≥25 kg/m2). Results Subjects in the overweight group had significantly worse biochemical indicators compared with underweight and normal weight subjects, but the frequency of strenuous exercise of the underweight subjects was significantly lower than that of the other two groups (P<0.001). Compared to the normal weight and overweight groups, the underweight group had lower level of forced expiratory volume in first second (FEV1), predicted FEV1(%), forced vital capacity (FVC), predicted FVC(%), and peak expiratory flow (PEF) (P<0.001), but higher level of FEV1/FVC, as well as predicted FEV1 (%)<80% and predicted FVC (%)<80%. Multivariate logistic regression model analysis showed that after adjusting for multiple confounding factors, the risk of reduced lung function in underweight group increased significantly, and the odd ratios were 2.10 (95%CI 1.98–2.21) and 4.90 (95%CI 4.62–5.18) for FEV1(%)<80% and FVC%<80%, respectively. Conclusion This study demonstrated that in the general population, the underweight was significantly associated with reduced lung function.