Importance: Chronic bronchitis has been associated with cigarette smoking as well as with e-cigarette use among young adults, but the association of chronic bronchitis in persons without airflow obstruction or clinical asthma, described as nonobstructive chronic bronchitis, with respiratory health outcomes remains uncertain. Objective: To assess whether nonobstructive chronic bronchitis is associated with adverse respiratory health outcomes in adult ever smokers and never smokers. Design, Setting, and Participants: This prospective cohort study included 22325 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. The National Heart, Lung, and Blood Institute (NHLBI) Pooled Cohorts Study harmonized and pooled data from 9 US general population-based cohorts. Thus present study is based on data from 5 of these cohorts. Participants were enrolled from August 1971 through May 2007 and were followed up through December 2018. Exposures: Nonobstructive chronic bronchitis was defined by questionnaire at baseline as both cough and phlegm for at least 3 months for at least 2 consecutive years. Main Outcomes and Measures: Lung function was measured by prebronchodilator spirometry. Hospitalizations and deaths due to chronic lower respiratory disease and respiratory disease-related mortality were defined by events adjudication and administrative criteria. Models were stratified by smoking status and adjusted for anthropometric, sociodemographic, and smoking-related factors. The comparison group was participants without nonobstructive chronic bronchitis. Results: Among 22325 adults included in the analysis, mean (SD) age was 53.0 (16.3) years (range, 18.0-95.0 years), 58.2% were female, 65.9% were non-Hispanic white, and 49.6% were ever smokers. Among 11082 ever smokers with 99869 person-years of follow-up, participants with nonobstructive chronic bronchitis (300 [2.7%]) had accelerated decreases in FEV1 (4.1 mL/y; 95% CI, 2.1-6.1 mL/y) and FVC (4.7 mL/y; 95% CI, 2.2-7.2 mL/y), increased risks of chronic lower respiratory disease-related hospitalization or mortality (hazard ratio [HR], 2.2; 95% CI, 1.7-2.7), and greater respiratory disease-related (HR, 2.0; 95% CI, 1.1-3.8) and all-cause mortality (HR, 1.5; 95% CI, 1.3-1.8) compared with ever smokers without nonobstructive chronic bronchitis. Among 11243 never smokers with 120004 person-years of follow-up, participants with nonobstructive chronic bronchitis (151 [1.3%]) had greater rates of chronic lower respiratory disease-related hospitalization or mortality (HR, 3.1; 95% CI, 2.1-4.5) compared with never smokers without nonobstructive chronic bronchitis. Nonobstructive chronic bronchitis was not associated with FEV1:FVC decline or incident airflow obstruction. The presence of at least 1 of the component symptoms of nonobstructive chronic bronchitis (ie, chronic cough or phlegm), which was common in both ever smokers (11.0%) and never smokers (6.7%), was associated with adverse respiratory health outcomes. Conclusions and Relevance: The findings suggest that nonobstructive chronic bronchitis is associated with adverse respiratory health outcomes, particularly in ever smokers, and may be a high-risk phenotype suitable for risk stratification and targeted therapies.
Bibliographical noteFunding Information:
Study was funded by grants R21 HL129924 and K23 HL130627 from the NHLBI, NIH, with additional funding for analyses from grants R01-HL077612 and R01-HL093081 from the NHLBI. The ARIC Study has been funded in whole or in part with federal funds from the NHLBI, NIH, and the Department of Health and Human Services under contracts HHSN268201700001I, HHSN268201700003I, HHSN268201700005I, HHSN268201700004I, and HHSN2682017000021. The Coronary Artery Risk Development in Young Adults (CARDIA) Study was conducted and supported by the NHLBI in collaboration with grants HHSN268201800005I and HHSN268201800007I from the University of Alabama at Birmingham, grant HHSN268201800003I from Northwestern University, grant HHSN268201800006I from the University of Minnesota, and grant HHSN268201800004I from the Kaiser Foundation Research Institute. The CARDIA Study was also partially supported by the Intramural Research Program of the NIA and an intra-agency agreement AG0005 between the NIA and the NHLBI, as well as by grant R01 HL122477 (Dr Kalhan) from the NHLBI. The Cardiovascular Health Study (CHS) was supported by contracts HHSN268201200036C, HHSN268200800007C, HHSN268201800001C, N01HC55222, N01HC85079, N01HC85080, N01HC85081, N01HC85082, N01HC85083, and N01HC85086 and grants U01HL080295 and U01HL130114 from the NHLBI, with additional contributions from the National Institute of Neurological Disorders and Stroke. Additional support was provided by grant R01AG023629 from the NIA. A full list of principal CHS investigators and institutions can be found at CHS-NHLBI.org. The Framingham Offspring Cohort was supported by the Framingham Heart Study of the NHLBI, NIH and Boston University School of Medicine. The Framingham Offspring Cohort was supported by contract N01-HC-25195 and HHSN268201500001I from the NHLBI’s Framingham Heart Study. The Multi-Ethnic Study of Atherosclerosis (MESA)–Lung Study was supported by grants R01-HL-077612, R01-HL-093081, R01-HL130605, RC1-HL-100543, N01-HC-95159, N01-HC-95160, N01-HC-95161, N01-HC-95162, N01-HC-95163, N01-HC-95164, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, and N01-HC-95169 from the NHLBI, NIH. This publication was also developed under a Science to Achieve Results research assistance agreement RD831697 (MESA Air), awarded but not formally reviewed by the US Environmental Protection Agency.
reported receiving grants from the National Heart, Lung, and Blood Institute (NHLBI) during the conduct of the study and receiving grants from the NHLBI and from the COPD Foundation outside the submitted work. Dr Kalhan reported receiving grants from the NHLBI during the conduct of the study and receiving personal fees from AstraZeneca, Boehringer Ingelheim, Boston Consulting Group, Boston Scientific, CVS Caremark, and GlaxoSmithKline outside the submitted work. Dr Kronmal reported receiving grants from the NHLBI during the conduct of the study. Dr Loehr reported receiving grants and contracts as an investigator with the Atherosclerosis Risk in Communities (ARIC) Study from the NHLBI during the conduct of the study. Dr Newman reported receiving grants from the National Institute on Aging (NIA) during the conduct of the study. Dr O'Connor reported receiving grants from the National Institutes of Health (NIH) during the conduct of the study and receiving personal fees from AstraZeneca and grants from Janssen
Pharmaceuticals outside the submitted work. Dr Schwartz reported receiving grants from the NHLBI, NIH during the conduct of the study. Dr B. M. Smith reported receiving grants from the NIH during the conduct of the study and receiving grants from the Canadian Institutes of Health, the Quebec Health Research Fund, and the Quebec Lung Association outside the submitted work. Dr L. J. Smith reported receiving grants from the NHLBI, NIH during the conduct of the study. Dr Oelsner reported receiving grants from the NHLBI, NIH during the conduct of the study. No other disclosures were reported.
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PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural
- Research Support, N.I.H., Intramural
- Research Support, Non-U.S. Gov't
- Research Support, U.S. Gov't, Non-P.H.S.