HealthDay News — Smokers typically die at least a decade earlier than nonsmokers, but this can be at least partially reversed by quitting smoking, study findings suggest.
All-cause mortality was three times higher for smokers than for nonsmokers, with a hazard ratio of 2.8 (95% CI 2.4 to 3.1) for men and 3 (95% CI 2.7 to 3.3) for women, Prabhat Jha, MD, of the Center for Global Health Research in Toronto, and colleagues reported in New England Journal of Medicine.
This excess mortality was largely due to diseases that could be caused by smoking, including neoplastic, vascular, and respiratory diseases.
Jha and colleagues reviewed the smoking and smoking-cessation histories of 202,248 adults, aged 25 years and older who participated in the U.S. National Health Interview Survey during the years 1997 to 2004. During about 7 years of follow-up, 8,236 women and 7,479 men died.
Never smokers were twice as likely to live to age 80 compared with current smokers, the researchers found. Among men, the likelihood of living to 80 was 61% (95% CI: 55-67) for nonsmokers, but fell to just 26% (95% CI 18 to 33) for those who continued to smoke.
Among women women, nonsmokers had a 70% (95% CI: 64-76) likelihood of living to 80, whereas smokers had only a 38% (95% CI: 30-45) likelihood, according to Jha and colleagues.
The life expectancy of current smokers was more than 10 years shorter than that of never smokers, but quitting can help reverse this trend. Those who quit smoking between 25 to 34 years of age gained about six years of life, whereas those who stopped between ages 55 and 64 gained 4 years.
Overall, smoking cessation by about age 40 reduced mortality by 90%, the researchers found.
Study limitation include the possibility of confounding variables and cause of death misclassification.