Association of Body Composition with Pulmonary Function in Ningxia: The China Northwest Cohort

Background: In recent decades, obesity has become an epidemic worldwide and is a risk factor for many chronic diseases. Lung function is also a predictor of various chronic diseases. However, research results on the association between obesity and lung function are inconsistent and few studies have evaluated the association between central obesity indicators and lung function. Therefore, this study explored the correlation between central obesity and lung function. Methods: This study is a cross-sectional study. The basic participant characteristics were collected by questionnaire. A tape measure was used to measure waist circumference (WC) and hip circumference (HC). Body fat percentage was measured using an InBody370. Lung function parameters were measured using a digital spirometer connected to a computer (Chestgraph HI-101). R (R4.0.5) software was used for data analysis. A generalized linear model was used to analyze the association between obesity and lung function. Results: This study found that body mass index (BMI) adjusted for WC was negatively correlated with forced vital capacity (FVC) ([beta]=-0.05 [-0.06, -0.03] in men, [beta]=-0.05 [-0.07, -0.04] in women) and forced expiratory volume in 1 s (FEV1)([beta]=-0.02 [-0.03, -0.00] in men, [beta]=-0.03 [-0.04, -0.02] in women). Body fat percentage was negatively correlated with FVC ([beta]=-0.01 [-0.01, -0.01] in men, [beta]=-0.01 [-0.01, -0.00] in women). Conclusion: Central obesity and combined central and general obesity were more strongly positively correlated with lung function. WC-adjusted BMI was negatively correlated with lung function. Body fat percentage was negatively correlated with lung function. Keywords: lung function, central obesity, body mass index, waist circumference