Balte PP, Chaves PHM, Couper DJ, et al. - This prospective cohort study designed to evaluate whether nonobstructive chronic bronchitis is correlated with adverse respiratory health outcomes in adult ever smokers and never smokers. This research recruited a total of 22,325 adults without initial airflow obstruction (defined as the ratio of forced expiratory volume in the first second [FEV1] to forced vital capacity [FVC] of <0.70) or clinical asthma at baseline. Individuals were included between August 1971 and May 2007 and were followed up through December 2018. The outcomes of this study demonstrated that nonobstructive chronic bronchitis is correlated with adverse respiratory health outcomes, especially in ever smokers, and maybe a high-risk phenotype suitable for risk stratification and targeted therapies.