title: Smoking cessation--but not smoking reduction--improves the annual decline in FEV1 in occupationally exposed workers.
abstract: BACKGROUND
  Individuals exposed both to cigarette smoke and respiratory pollutants at work incur a greater risk of development of airway hyperresponsiveness (AHR) and accelerated decline in forced expiratory volume in 1 s (FEV1) than that incurred by subjects undergoing each exposure separately. We examined whether smoking cessation or smoking reduction improves AHR and thereby slows down the decline in FEV1 in occupationally exposed workers.
  
  
  METHODS
  We examined 165 workers (137 males and 28 females) participating in a smoking cessation programme. Nicotine tablets were used for smoking cessation or smoking reduction. Respiratory symptoms were assessed by questionnaire, FEV1 by spirometry and AHR by methacholine challenge test. At 1 year, subjects were classified into quitters, reducers, or continuing smokers.
  
  
  RESULTS
  Sixty-seven subjects completed the study (32 quitters; 17 reducers; 18 continuing smokers). Respiratory symptoms improved markedly in quitters (P<0.001 for all comparisons) and less so in reducers (P values between 0.163 and 0.027). At 1 year, FEV1 had slightly but significantly improved in quitters (P=0.006 vs. smokers; P=0.038 vs. reducers) and markedly deteriorated in reducers and continuing smokers. Concurrent, 1-year change in AHR did not differ significantly among the groups.
  
  
  CONCLUSIONS
  In occupationally exposed workers, stopping smoking markedly improved respiratory symptoms and, in males, slowed the annual decline in FEV1. Smoking reduction resulted in smaller improvements in symptoms but deterioration in FEV1. These findings were independent of AHR. While smoking cessation should remain the ultimate goal in workplace cessation programmes more studies are necessary to better ascertain the benefits of smoking reduction.
authors.affiliation: INSERM ERI 11, Faculté de Médecine, B.P. 184-9, Av de la Forêt de Haye, 54505 Vandoeuvre-lès-Nancy Cedex, France. abraham.bohadana@nancy.inserm.fr
authors.forename: Abraham B
authors.initials: AB
authors.lastname: Bohadana
authors.forename: Fredrik
authors.initials: F
authors.lastname: Nilsson
authors.forename: Ake
authors.initials: A
authors.lastname: Westin
authors.forename: Nadine
authors.initials: N
authors.lastname: Martinet
authors.forename: Yves
authors.initials: Y
authors.lastname: Martinet
mesh_terms: D000328:Adult; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D016273:Occupational Exposure / Q000009:adverse effects*; D011446:Prospective Studies; D012130:Respiratory Hypersensitivity / Q000517:prevention & control*; D012907:Smoking / Q000009:adverse effects*; D016540:Smoking Cessation