Low BMI and weight loss aggravate COPD mortality in men, findings from a large prospective cohort: the JACC study.

To clarify how low BMI and weight loss were associated with risk of chronic obstructive pulmonary disease (COPD) mortality, in a large prospective cohort of the general population across Japan, the Japan Collaborative Cohort Study, conducted between 1988 and 2009. A total of 45,837 male residents were observed for a median period of 19.1 years. Self-administered questionnaires, collecting information on BMI, weight loss since the age of 20, lifestyles, history of diseases, as well as records of COPD mortality, were analysed at 2019. During follow-up, 268 participants died from COPD. The multivariate-adjusted hazard ratio (95% confidence interval) of COPD mortality associated with a 1-SD increment of body mass index (BMI) was 0.48 (0.41-0.57), while for weight change from age of 20 (+ 2.0 kg) it was 0.63 (0.59-0.68). These associations were persistently observed after stratifications with smoking status, excluding those having airway symptoms in the baseline survey, and excluding early COPD deaths within 5, 10 and 15 years. Our study suggests that BMI and weight change since the age of 20 could be markers for COPD prognosis, indicated by risk of COPD mortality.