Smoking death risks significantly reduced within five years of quitting
Women who quit smoking have about a 20 percent lower risk of death from smoking-related cancers within five years of quitting, as well as a substantially reduced risk of death from heart disease, according to researchers at Harvard School of Public Health in Boston.
The team analysed data on 104,519 women from 1980 to 2004 whose details were contained in the Nurses' Health Study.
They found that, within the first five years of giving up cigarettes, the risk of dying from any cause fell by 13 per cent. The excess risk caused by smoking was entirely eliminated 20 years after quitting.
Publishing their findings in the Journal of the American Medical Association, the researchers wrote: "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 five years for vascular diseases compared with other causes.
"For death due to respiratory disease, an 18 per cent reduction in risk of death was observed five to ten years after quitting smoking, with the risk reaching that of a never smoker's risk after 20 years."
For lung cancer in particular, researchers noted a 21 per cent reduction in risk within the first five years of quitting, but the remaining excess risk was not eliminated for 30 years.
When other smoking-related cancers were taken into account, the excess risk remained for more than 20 years compared to people who had never smoked.
The data also revealed that smoking was associated with an elevated risk of death from bowel cancer but not ovarian cancer, and that 64 per cent of deaths among current smokers and 28 per cent among former smokers were due to smoking.
The researchers concluded: "Early age at initiation is associated with an increased mortality risk so implementing and maintaining school tobacco prevention programmes, in addition to enforcing youth access laws, are key preventive strategies.
"Effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programmes."