Study shows effects of quitting smoking significant within five years

CHICAGO Women who quit smoking significantly reduce their risk of death from coronary heart disease within five years and have about a 20 percent lower risk of death from smoking-related cancers within that time period, according to a study in the May 7 issue of the Journal of the American Medical Association.

Stacey Kenfield, of the Harvard School of Public Health, Boston, and colleagues assessed the relationship between cigarette smoking and smoking cessation on total and cause-specific mortality in women by analyzing data from the Nurses’ Health Study, an observational study of 104,519 female participants, with follow-up from 1980 to 2004. A total of 12,483 deaths occurred in this group, 4,485 (35.9 percent) among women who never smoked, 3,602 (28.9 percent) among current smokers and 4,396 (35.2 percent) among past smokers.

The researchers found a significant 13 percent reduction in the risk of all-cause mortality within the first 5 years of quitting smoking compared with continuing to smoke, and the excess risk decreased to the level of a who never smoked 20 years after quitting, with some causes taking more or less time. “Significant trends were observed with increasing years since quitting for all major cause-specific outcomes,” Kenfield noted. “A more rapid decline in risk after quitting smoking compared with continuing to smoke was observed in the first 5 years for vascular diseases compared with other causes.”