戒烟者和少量吸烟者肺功能仍更快下降

Lung function decline in former smokers and low-intensity current smokers: a secondary data analysis of the NHLBI Pooled Cohorts Study

• Oelsner EC, Balte PP, Bhatt SP, et al. Lung function decline in former smokers and low-intensity current smokers: a secondary data analysis of the NHLBI Pooled Cohorts Study. The Lancet Respiratory Medicine 2020;8:34-44.
• Correspondence to: Dr Elizabeth C Oelsner, Division of General Medicine, Columbia University Medical Center, New York, NY 10032, USA eco7@cumc.columbia.edu

Background 背景

Former smokers now outnumber current smokers in many developed countries, and current smokers are smoking fewer cigarettes per day. Some data suggest that lung function decline normalises with smoking cessation; however, mechanistic studies suggest that lung function decline could continue. We hypothesised that former smokers and low-intensity current smokers have accelerated lung function decline compared with never- smokers, including among those without prevalent lung disease.

在许多发达国家，戒烟的人比在吸烟的人多，而且现在吸烟者每天抽的烟也越来越少。一些数据表明，戒烟后肺功能恢复正常;然而，机制研究表明，肺功能下降可能会继续。我们假设，与从不吸烟的人(包括那些没有普遍肺部疾病的人)相比，已戒烟者和少量吸烟者的肺功能下降速度更快。

Methods 方法

We used data on six US population-based cohorts included in the NHLBI Pooled Cohort Study. We restricted the sample to participants with valid spirometry at two or more exams. Two cohorts recruited younger adults (≥17 years), two recruited middle-aged and older adults (≥45 years), and two recruited only elderly adults (≥65 years) with examinations done between 1983 and 2014. FEV1 decline in sustained former smokers and current smokers was compared to that of never-smokers by use of mixed models adjusted for sociodemographic and anthropometric factors. Differential FEV1 decline was also evaluated according to duration of smoking cessation and cumulative (number of pack-years) and current (number of cigarettes per day) cigarette consumption.

我们使用了NHLBI联合队列研究中包含的6个以美国人群为基础的队列的数据。我们限制样本中的参与者有效的肺活量测定在两个或更多的检查。两个队列招募年轻人(≥17岁)，两个招募中年人和老年人(≥45岁)，两个招募老年人(≥65岁)，并在1983年至2014年间进行检查。通过使用根据社会人口统计学和人体测量学因素调整的混合模型，将持续吸烟者和当前吸烟者的FEV1下降情况与从不吸烟者进行比较。根据戒烟持续时间、累计(吸的包数)和当前(每天吸多少支烟)的香烟消费量来评估FEV1的差异下降。

Findings 发现

25 352 participants (ages 17–93 years) completed 70 228 valid spirometry exams. Over a median follow-up of 7 years (IQR 3–20), FEV1 decline at the median age (57 years) was 31.01 mL per year (95% CI 30.66–31.37) in sustained never-smokers, 34.97 mL per year (34.36–35.57) in former smokers, and 39.92 mL per year (38.92–40.92) in current smokers. With adjustment, former smokers showed an accelerated FEV1 decline of 1.82 mL per year (95% CI 1.24–2.40) compared to never-smokers, which was approximately 20% of the effect estimate for current smokers (9.21 mL per year; 95% CI 8.35–10.08).

25 352名参与者(年龄17-93岁)完成了70 228项有效的肺活量测试。中位随访7年(IQR 3-20)，中位年龄(57岁)的FEV1下降在持续不吸烟者中为每年31.01 mL (95% CI 30.66-31.37)，在已戒烟者中为每年34.97 mL(34.36-35.57)，在现吸烟者中为每年39.92 mL(38.92-40.92)。经过校正后，与从不吸烟的人相比，已经戒烟的人FEV1每年下降1.82毫升(95%可信区间为1.24-2.40)，这大约是目前吸烟者估计值的20%(每年9.21毫升;95%可信区间8.35 - -10.08)。

Compared to never-smokers, accelerated FEV1 decline was observed in former smokers for decades after smoking cessation and in current smokers with low cumulative cigarette consumption (<10 pack-years). With respect to current cigarette consumption, the effect estimate for FEV1 decline in current smokers consuming less than five cigarettes per day (7.65 mL per year; 95% CI 6.21–9.09) was 68% of that in current smokers consuming 30 or more cigarettes per day (11.24 mL per year; 9.86–12.62), and around five times greater than in former smokers (1.57 mL per year; 1.00–2.14). Among participants without prevalent lung disease, associations were attenuated but were consistent with the main results.

与从不吸烟的人相比，在戒烟后的几十年里，曾吸烟者和现在少量 (少于10包年)吸烟者的FEV1下降速度更快。就目前的香烟消费量而言，据估计，FEV1下降估计值，对于目前每天吸烟少于五支的吸烟者(每年7.65毫升;95% CI 6.21-9.09)是当前吸烟者（每天消费30支或更多香烟）的68%(每年11.24毫升;9.86-12.62)，而大约是已戒烟者的5倍(每年1.57毫升;1.00 - -2.14)。在没有流行肺部疾病的参与者中，相关性减弱，但与主要结果一致。

Interpretation 意义

Former smokers and low-intensity current smokers have accelerated lung function decline compared with never-smokers. These results suggest that all levels of smoking exposure are likely to be associated with lasting and progressive lung damage.

与从不吸烟的人相比，已戒烟者和少量吸烟者的肺功能下降速度更快。这些结果表明，所有水平的吸烟暴露都可能与持续和渐进的肺损伤有关。