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.
在許多已開發國家，戒菸的人比在吸菸的人多，而且現在吸菸者每天抽的煙也越來越少。一些數據表明，戒菸後肺功能恢復正常;然而，機制研究表明，肺功能下降可能會繼續。我們假設，與從不吸菸的人(包括那些沒有普遍肺部疾病的人)相比，已戒菸者和少量吸菸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.
我們使用了NHLBI聯合隊列研究中包含的6個以美國人群為基礎的隊列的數據。我們限制樣本中的參與者有效的肺活量測定在兩個或更多的檢查。兩個隊列招募年輕人(≥17歲)，兩個招募中年人和老年人(≥45歲)，兩個招募老年人(≥65歲)，並在1983年至2014年間進行檢查。通過使用根據社會人口統計學和人體測量學因素調整的混合模型，將持續吸菸者和當前吸菸者的FEV1下降情況與從不吸菸者進行比較。根據戒菸持續時間、累計(吸的包數)和當前(每天吸多少支煙)的香菸消費量來評估FEV1的差異下降。
Findings 發現
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名參與者(年齡17-93歲)完成了70 228項有效的肺活量測試。中位隨訪7年(IQR 3-20)，中位年齡(57歲)的FEV1下降在持續不吸菸者中為每年31.01 mL (95% CI 30.66-31.37)，在已戒菸者中為每年34.97 mL(34.36-35.57)，在現吸菸者中為每年39.92 mL(38.92-40.92)。經過校正後，與從不吸菸的人相比，已經戒菸的人FEV1每年下降1.82毫升(95%可信區間為1.24-2.40)，這大約是目前吸菸者估計值的20%(每年9.21毫升;95%可信區間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.
與從不吸菸的人相比，在戒菸後的幾十年里，曾吸菸者和現在少量 (少於10包年)吸菸者的FEV1下降速度更快。就目前的香菸消費量而言，據估計，FEV1下降估計值，對於目前每天吸菸少於五支的吸菸者(每年7.65毫升;95% CI 6.21-9.09)是當前吸菸者（每天消費30支或更多香菸）的68%(每年11.24毫升;9.86-12.62)，而大約是已戒菸者的5倍(每年1.57毫升;1.00 - -2.14)。在沒有流行肺部疾病的參與者中，相關性減弱，但與主要結果一致。
Interpretation 意義
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.
與從不吸菸的人相比，已戒菸者和少量吸菸者的肺功能下降速度更快。這些結果表明，所有水平的吸菸暴露都可能與持續和漸進的肺損傷有關。