Résumé :
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[BDSP. Notice produite par INIST R0xQl6cY. Diffusion soumise à autorisation]. Background. This study was undertaken to test the constitutional hypothesis which attributes the association of tobacco smoking with morbidity and mortality to genetic predispositions to smoking and/or disease. Methods. Subjects were World War II veterans, born in the US between 1917 and 1927, and surveyed at mean age 47 for present and past smoking habits. Twenty-four year mortality follow-up data were available for 1515 male twin pairs discordant for lifelong cigarette smoking. Using the first or only death of a smoking-discordant pair, 24-year relative risks of mortality were calculated by zygosity, cause of death, amount smoked, and age at death. Results. We found that active smokers at baseline, regardless of zygosity, had a higher risk of death than their co-twins who had never smoked or quit smoking (monozygotic pairs : relative risk [RR]=2.5 ; 95% confidence interval [Cl] : 1.3-6.1 and RR=1.7 ; 95% Cl : 1.2-2.5 ; dizygotic pairs : RR=2.4 ; 95% Cl : 1.4-3.8 and RR=2.0 ; 95% Cl : 1.7-3.3). The elevated risk of death among smokers was due to deaths from lung cancer (monozygotic pairs : RR=5.0 ; 95% Cl : 2.6-15.0 ; dizygotic pairs : RR=11.0 ; 95% Cl : 4.3-45.0) or deaths from cardiovascular diseases (monozygotic pairs : RR=3.9 ; 95% Cl : 1.9-11.5 ; dizygotic pairs : RR=2.8 ; 95% Cl : 1.7-4.9). Apart from these findings the relationship of smoking with all-cause mortality was stronger for earlier/younger deaths and for heavy to moderate smoking. Conclusions. (...)
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