Lung Function Decline Persists Decades After Smoking Cessation
Even smoking less that 5 cigarettes a day causes damage to lung function that can last for decades, according to the results of a recent study.
Previous data has suggested that lung function normalizes following smoking cessation, while some studies have suggested that these declines could continue.
To further explore the effects of smoking cessation on lung function, the researchers examined data from 6 US population-based cohorts included in the NHLBI Pooled Cohort Study. They included participants with valid spirometry at 2 or more exams, and participants from the 6 studies varied from individuals aged 17 years or older to those aged 65 years or older. Overall, 25,352 participants completed 70,228 spirometry exams.
Over a median follow-up of 7 years, FEV1 decline at the median age of 57 years was 31.01 mL per year is sustained never-smokers, 34.97 mL per year in former smokers, and 29.92 mL per year in current smokers. After adjustment, former smokers showed an accelerated FEV1 decline of 1.82 mL per year compared with never-smokers. These declines were observed in former smokers for decades after smoking cessation and in current smokers with low cigarette consumption (<10 pack-years). Notably, the effect estimate for FEV1 decline in current smokers who consumed less than 5 cigarettes each day was 68% of that in current smokers who consumed 30 or more cigarettes each day and roughly 5-times greater than that observed in former smokers.
“Former smokers and low-intensity current smokers have accelerated lung function decline compared with never-smokers," the researchers concluded. "These results suggest that all levels of smoking exposure are likely to be associated with lasting and progressive lung damage.”
—Michael Potts
Reference:
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 [published online October 9, 2019]. Lancet Resp Med. https://doi.org/10.1016/S2213-2600(19)30276-0.