Bioelectrical impedance and lung function—associations with gender and central obesity: results of the EpiHealth study

Abstract Background Obesity is a major public health concern associated with various health problems, including respiratory impairment. Bioelectrical impedance (BIA) is used in health screening to assess body fat. However, there is no consensus in healthcare on how body fat should be assessed in relation to lung function. In this study, we aimed to investigate how BIA in relation to waist circumference contribute, using data from a large Swedish population study. Methods A total of 17,097 participants (aged 45–75 years) were included in the study. The relationships between fat mass, waist circumference, and lung function were analysed using weighted quantile sum regression. Results Increased fat mass was significantly associated with decreased lung function (FEV1, FVC) in both sexes. Also, the influence of trunk fat and waist circumference on FVC and FEV1 differed by sex: in males, waist circumference and trunk fat had nearly equal importance for FVC (variable weights of 0.42 and 0.41), whereas in females, trunk fat was significantly more important (variable weights 0.84 and 0.14). For FEV1, waist circumference was more important in males, while trunk fat was more significant in females (variable weights male 0.68 and 0.28 and 0.23 and 0.77 in female). Conclusions Our results suggest that trunk fat should be considered when assessing the impact of adipose tissue on lung function and should potentially be included in the health controls.