Leem AY, et al. -The relationship between serum bilirubin concentration and annual lung function decline was evaluated in the Korean general population. Researchers analyzed 7,986 subjects aged 40–69 years from the Ansung-Ansan cohort database I (2001–2002)–III (2005–2006), to assess the relationships between serum bilirubin level and forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC, and mean forced expiratory flow between 25% and 75% of FVC (FEF_25%–75%) at baseline, as well as the annual average changes in these lung parameters. The general population, especially the never-smokers, demonstrated significant associations of serum bilirubin levels with FEV₁, FVC, and FEF_25%–75%. Moreover, there appeared an association of serum bilirubin levels with the annual decline in FEV₁, FVC, and FEV₁/FVC ratio.