Résumé :
|
[BDSP. Notice produite par INIST-CNRS nR0xdkMi. Diffusion soumise à autorisation]. The authors investigated the association between changes in smoking habits and mortality by pooling data from three large cohort studies conducted in Copenhagen, Denmark. The study included a total of 19,732 persons who had been examined between 1967 and 1988, with reexaminations at 5-to 10-year intervals and a mean follow-up of 15.5 years. Date of death and cause of death were obtained by record linkage with nationwide registers. By means of Cox proportional hazards models, heavy smokers (>=15 cigarettes/day) who reduced their daily tobacco intake by at least 50% without quitting between the first two examinations and participants who quit smoking were compared with persons who continued to smoke heavily. After exclusion of deaths occurring in the first 2 years of follow-up, the authors found the following adjusted hazard ratios for subjects who reduced their smoking : for cardiovascular diseases, hazard ratio (HR)=1.01 (95% confidence interval (Cl) : 0.76,1.35) ; for respiratory diseases, HR=1.20 (95% Cl : 0.70,2.07) ; for tobacco-related cancers, HR=0.91 (95% Cl : 0.63,1.31) ; and for all-cause mortality, HR=1.02 (95% Cl : 0.89,1.17). In subjects who stopped smoking, most estimates were significantly lower than the heavy smokers'These results suggest that smoking reduction is not associated with a decrease in mortality from tobacco-related diseases. The data confirm that smoking cessation reduces mortality risk.
|