Abstract

STUDY OBJECTIVE--The aim was to measure experimentally the effects in middle aged men of stopping smoking. DESIGN--The study was a randomised controlled trial. SETTING AND SUBJECTS--The subjects were 1445 male smokers, initially aged 40-59 years, who were selected from the Whitehall study survey of 16,016 civil servants on the basis of a high risk of cardiorespiratory disease. MAIN RESULTS--During the next 20 years there were 620 deaths (231 from coronary heart disease), 96 cases of lung cancer, and 159 other cancers. Comparing the intervention with the normal care group, total mortality was 7% lower, fatal coronary heart disease was 13% lower, and lung cancer (deaths+registrations) was 11% lower. An excess rate for other cancers, reported previously, did not persist into the second decade of the trial. CONCLUSIONS--The results are consistent with observational studies, implying that smoking cessation by middle aged men substantially improves their changes of avoiding lung cancer or a fatal heart attack. Our estimate from the trial is that out of every 100 men who stopped smoking, between six and 10 were in consequence alive 20 years later.