The longitudinal impact of body compartments on lung function in children, adolescents, and adults

Abstract

<b>Background:</b> Evidence shows associations between body weight and lung function, but the longitudinal effects of specific body compartments and their changes on lung function trajectories remain unclear. We aimed to investigate the influence of body compartments and changes over time on lung function measures, including static lung volumes. <b>Methods:</b> We investigated 10602 adults (≥18-82 years) and 1489 children/adolescents (6-18 years) of the population-based LEAD cohort. Lung function by spirometry (FEV1, FVC) and body plethysmography (TLC, RV, FRC) were compared between individuals with different amounts of fat mass index (FMI) and appendicular lean mass index (ALMI) assessed by DXA. Lung function changes in body compartments were assessed after four years. Findings: High ALMI was consistently associated with higher FEV1 and FVC in children/adolescents and adults, and with higher TLC in children/adolescents. In adults, an inverse association existed between FMI and all lung function measures, while children/adolescents with high FMI had higher FVC. In children/adolescents with increasing ALMI, FVC and TLC increased, while in adults with increasing FMI, static lung measures (TLC, RV, FRC) declined. <b>Conclusion:</b> This study demonstrates the impact of body composition on various lung function measures. Muscle mass influences forced parameters, especially in children/adolescents,&nbsp;while fat mass impacts static lung function measures more strongly. Lung function trajectories should be interepreted considering changes in body comparments in the future.