The Effects of Smoking Cessation amongst Asbestos Workers from Wittenoom Gorge

From a cohort of 6497 male employees of the Australian Blue Asbestos Company between 1943 and 1966, 2400 replied to a questionnaire on smoking in 1979. Forty-nine per cent stated that they were current smokers, 30% that they were ex-smokers and 21 % that they had never smoked. All current smokers were provided with information on the effects of smoking and counselled to stop by a letter containing smoking cessation advice. All subjects have been followed to December 1986 to obtain their vital status, date of diagnosis of cancer, or cause of death. The incidence of cancer and mortality have been examined according to the subjects' known exposure to crocidolite and smoking status. Further information on smoking status was obtained by mail in 1985 and 1989. The incidence rates for lung cancer and death rates from all causes in those who had never smoked have been applied to the current smokers and ex-smokers to predict the effect of stopping smoking in 1979. Smoking has made a major contribution to death and disease in this cohort of crocidolite workers. Forty per cent of the smoking-related excess deaths were due to lung cancer (in both current smokers and ex-smokers). There were 60 deaths attributable to smoking and 52 attributable to asbestos exposure between 1979 and 1986. If all subjects had never smoked there would have been about 30 (95% CI, 7–48) less cases of lung cancer and 60 (95% CI, −3 to 124) less deaths from all causes in this cohort by the end of 1986. If all subjects who smoked had quit in 1979 it is predicted that there would be about 130 fewer cases of lung cancer and 260 fewer deaths from all causes by the year 2010.