Smoking cessation-but not smoking reduction-improves the annual decline in FEV(1) in occupationally exposed workers.

Bohadana AB, Nilsson F, Westin A, Martinet N, Martinet Y
Respir Med. 2005 Dec 12
INSERM ERI 11, Faculte de Medecine, B.P. 184-9, Av de la Foret de Haye, 54505 Vandoeuvre-les-Nancy Cedex, France; Service de Pneumologie, CHU de Nancy, INSERM EMI 0014, Vandoeuvre-les-Nancy, France.

INTRODUCTION: 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 1s (FEV(1)) 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 FEV(1) 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, FEV(1) 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, FEV(1) 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.

CONCLUSION: In occupationally exposed workers, stopping smoking markedly improved respiratory symptoms and, in males, slowed the annual decline in FEV(1). Smoking reduction resulted in smaller improvements in symptoms but deterioration in FEV(1). 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.




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