Table 1—

Effects of smoking cessation on chronic obstructive pulmonary disease(COPD) morbidity

First author [ref.]StudySubjects nAge yrsFollow-up# yrsΔFEV1 mL·yr−1Summary effectComments
Clinically based
 Fletcher 15London, UK792 working M30–598-80 (heavy smokers), -62 (light smokers), -37 (ex-smokers) with mild obstruction+Spirometry was performed every 6 months
 Hughes 13London, UK56 M with emphysema45–633–13-58 (smokers), -15 (ex-smokers; p<0.001)+Greater VC decline in smokers than ex-smokers
 Anthonisen 12NIH (USA)985 COPD Pts (FEV1 < 60% pred)53–683-44 (smokers, ex-smokers)0Spirometry was performed every 3 months.
 Postma 14Groningen, NL81 moderate–severe COPD Pts39–572–21-85 (smokers), -49 (ex-smokers; p<0.05)+
 Kessler 20Strasbourg, FR64 moderate–severe COPD Pts57–722.5ND0No difference in COPD exacerbation hospitalisation risk for ex- and current smokers (univariate analysis)
 Garcia-Aymerich 21Barcelona, ES86 Cs (hospitalised, COPD exacerbation); 86 C (stable COPD)60–78Cross-sectionalND-Current smoking associated with less hospitalisation than ex-smoking (OR 0.30)
 Kanner 18LHS (USA)5887 mild–moderate COPD Pts35–605Greater decline in smokers, but not ex-smokers, with more than one LRTI annually (p = 0.0001)+Ex-smokers had fewer self-reported LRTI episodes than current smokers (p = 0.0003)
 Anthonisen 8LHS (USA)5887 mild–moderate COPD Pts35–6011-66 (M smokers), -30 (M ex-smokers), -54 (F smokers), -22 (F ex-smokers)+
 Anthonisen 17LHS (USA)5887 mild–moderate COPD Pts35–605ND0No difference between treatment groups or smokers versus ex-smokers in hospitalisation rate for respiratory causes
 Makris 19Heraklion, GR102 moderate–severe COPD Pts60–70374 (decline faster in current than ex-smokers; p = 0.004)+Both current and ex-smokers with frequent COPD exacerbations had faster FEV1-decline
 Tashkin 27Los Angeles, CA, USA2401 (Gen Pop sample)25–645Same unquantified decline in current/ex-smoking M with COPD0/+Ex-smoking F with COPD had smaller declines than current smokers (p<0.002)
 Sherrill 28Tucson, AZ, USA3805 M/F (random cluster)≥1817M quitters in lowest FEV1/FVC quartile had similar decline to current smokers0/+F quitters in the lowest FEV1/FVC quartile had slower decline than current smokers
 Burchfiel 22Honolulu Heart Program (USA)4451 Japanese–American M45–686-18.8 (quitters with COPD, n = 64), -31.4 (smokers with COPD, n = 199; p = 0.024)+Adjusted for baseline FEV1 and amount smoked
 Pelkonen 23Helsinki, FI1711 M from two rural areas40–5915-62.9 (smokers), -48.4 (ex-smokers; p<0.001) in lowest FEV0.75 tertile+
 Godtfredsen 29Copenhagen, DK19709 (Gen Pop sample, three pooled studies)20–9314ND+Risk of hospitalisation for COPD lower in long-term ex-smokers (HR 0.30) and quitters (HR 0.53) than current smokers.
 LØkke 31Copenhagen DK8045 M/F from CCHS30–6025ND+OR for developing COPD showed increasing trend with shorter duration of smoking cessation compared to never-smokers
 Mannino 25Lexington, KY, USA15536 M/F from ARIC study44–663ND+OR for rapid FEV1 decline not higher in ex- than never-smokers (1.0); OR in current smokers 1.3 (95% CI 1.2–1.5)
 Lindberg 24Luleå, SE1109 M/F with RS36–6710-43/-35 (M/F smokers), -35/-27 (M/F ex-smokers; p<0.05)+Equal decline in never- and long-term ex-smokers; similar in quitters, re-starters and smokers
  • Δ: change; FEV1: forced expiratory volume in one second; NIH: National Institutes of Health; NL: the Netherlands; FR: France; ES: Spain; LHS: Lung Health Study; GR: Greece; FI: Finland; DK: Denmark; SE: Sweden; M: male; Pt: patient; % pred: % predicted; Cs: cases; C: controls; Gen Pop: general population; CCHS: Copenhagen City Heart Study; ARIC: Atherosclerosis Risk in Communities; RS: respiratory symptoms; ND: not determined; LRTI: lower respiratory tract illness; FVC: forced vital capacity; FEV0.75: forced expiratory volume in 0.75 seconds; VC: vital capacity; OR: odds ratio; F: female; HR: hazard ratio; CI: confidence interval; +: ex-smokers/quitters showed benefits over current smokers; -: current smokers showed benefits over ex-smokers/quitters; 0: no difference between the two groups. #: after smoking cessation.