Department of Medicine, Columbia University Medical Center, New York, New York.
Benjamin Leon Jr Family Center for Geriatric Research and Education, Florida International University, Miami, Florida.
JAMA Intern Med. 2020 May 1;180(5):676-686. doi: 10.1001/jamainternmed.2020.0104.
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.
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 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. 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.
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.
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.
Among 22 325 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 11 082 ever smokers with 99 869 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 11 243 never smokers with 120 004 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.
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.
慢性支气管炎与年轻人中的香烟吸烟和电子烟使用有关，但在没有气流阻塞或临床哮喘的患者中，描述为非阻塞性慢性支气管炎的慢性支气管炎与呼吸健康结果的关系仍不确定。
评估非阻塞性慢性支气管炎是否与成年吸烟者和不吸烟者的不良呼吸健康结果相关。
设计、地点和参与者：本前瞻性队列研究纳入了 22325 名基线时无初始气流阻塞（定义为第一秒用力呼气量与用力肺活量之比<0.70）或临床哮喘的成年人。国家心肺血液研究所（NHLBI） pooled cohorts 研究对 9 项美国基于人群的队列研究进行了协调和合并。因此，本研究基于其中 5 项队列研究的数据。参与者于 1971 年 8 月至 2007 年 5 月入组，并随访至 2018 年 12 月。
非阻塞性慢性支气管炎在基线时通过问卷定义为至少连续 2 年每年至少有 3 个月咳嗽和咳痰。
肺功能通过支气管扩张剂前的肺活量测定法进行测量。慢性下呼吸道疾病相关的住院和死亡以及与呼吸疾病相关的死亡率由事件裁决和行政标准定义。模型按吸烟状况和体重指数、社会人口统计学和吸烟相关因素进行分层。对照组为无非阻塞性慢性支气管炎的参与者。
在纳入分析的 22325 名成年人中，平均（标准差）年龄为 53.0（16.3）岁（范围，18.0-95.0 岁），58.2%为女性，65.9%为非西班牙裔白人，49.6%为曾吸烟者。在 11243 名曾吸烟者中，有 99869 人年的随访时间，患有非阻塞性慢性支气管炎（300 [2.7%]）的参与者 FEV1（4.1 毫升/年；95%CI，2.1-6.1 毫升/年）和 FVC（4.7 毫升/年；95%CI，2.2-7.2 毫升/年）下降加速，慢性下呼吸道疾病相关住院或死亡率增加（风险比[HR]，2.2；95%CI，1.7-2.7），与无非阻塞性慢性支气管炎的曾吸烟者相比，呼吸疾病相关（HR，2.0；95%CI，1.1-3.8）和全因死亡率（HR，1.5；95%CI，1.3-1.8）也更高。在 11243 名从不吸烟者中，有 120004 人年的随访时间，患有非阻塞性慢性支气管炎（151 [1.3%]）的参与者慢性下呼吸道疾病相关住院或死亡率更高（HR，3.1；95%CI，2.1-4.5），与无非阻塞性慢性支气管炎的从不吸烟者相比。非阻塞性慢性支气管炎与 FEV1:FVC 下降或新发生气流阻塞无关。至少存在非阻塞性慢性支气管炎的 1 种组成症状（即慢性咳嗽或咳痰）的情况在曾吸烟者（11.0%）和从不吸烟者（6.7%）中均很常见，与不良呼吸健康结果相关。
研究结果表明，非阻塞性慢性支气管炎与呼吸健康结果不良有关，特别是在曾吸烟者中，并且可能是一种适合风险分层和靶向治疗的高危表型。
