Women who quit smoking cut their risks of death from heart disease significantly within five years and have a 20 percent lower chance of dying from smoking-related cancers within that time period, says a new study.
The study led by Stacey A. Kenfield, Sc.D, of the Harvard School of Public Health, Boston examined the data from the Nurses' Health Study, an observational study including 104,519 female participants, with follow-up from 1980 to 2004.
They tried to assess the relationship between cigarette smoking and smoking cessation on total and cause-specific mortality in women by examining the data.
A total of 12,483 deaths occurred in this group, out of which 35.9 percent were non-smokers, 28.9 percent current smokers, and 35.2 percent among past smokers.
The findings revealed that there was 13 percent reduction in the risk of all-cause mortality within the first 5 years of quitting smoking compared with continuing to smoke. Moreover, the excess risk decreased to the level of a never smoker 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. 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," wrote the authors.
"Much of the reduction in the excess risk for these causes of death were realized within the first 5 years for coronary heart disease and cerebrovascular disease.
"Sixty-one percent of the full potential benefit of quitting in regard to coronary heart disease mortality and 42 percent of the full potential benefit of quitting in regard to cerebrovascular mortality was realized within the first 5 years of quitting smoking, when comparing hazard ratios for recent quitters of less than 5 years with long-term quitters of 20 years or greater.
"For death due to respiratory disease, an 18 percent reduction in risk of death was observed 5 to 10 years after quitting smoking, with the risk reaching that of a never smoker's risk after 20 years," they added.
For lung cancer mortality, a significant 21 percent reduction in risk was observed within the first 5 years compared with continuing smokers, but the excess risk did not disappear for 30 years.
Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs," said the authors.
The study appears in May 7 issue of JAMA.