Quit smoking and the benefits soon appear

New research says that people who give up smoking begin to improve their health almost immediately, and the risk of death from all causes falls by 13% within 5 years and to no extra risk of death by 20 years.

The study, by researchers at Harvard Medical School in Boston used data from the Nurses Health Study in the United States and health questionnaires from more than 120,000 women aged between 30 and 55 in 11 states from 1976 onwards.

The researchers were able to link answers to lifestyle questions - such as how much people smoked - to information about the volunteers' general health and how they died.

The questionnaires, which were repeated every two years, gave the team an evolving picture of the participants' habits and lives and they were able to compare women who had smoked but given up, with women who had never smoked or never given up.

The study by Dr. Stacey Kenfield and colleagues found that 64% of deaths among current smokers could be attributable to cigarettes, and 28% of deaths among former smokers.

Those who smoked 35 or more cigarettes a day were 115 times more likely to develop chronic bronchitis and emphysema and also upped their risk of lung cancer by 40 times.

While the research confirmed that smoking is a major cause of disease it also found that within five years of stopping smoking the risk of death from all causes fell by 13%, and by 20 years, people had no extra risk of death because of their past smoking history.

The findings will give heart to those who want to kick the habit as the health benefits of stopping appear quickly; for coronary heart disease, 61% of the full potential benefit from quitting happens in the first five years; for strokes 42%; for lung cancer 21%.

The research also found that the rates of mortality from respiratory disease, lung cancer and smoking-related cancer were all lower in women who had started smoking later.

The team say an early initiation into smoking is associated with an increased mortality risk therefore implementing and maintaining school tobacco prevention programs, in addition to enforcing youth access laws, are key preventive strategies.

They say effectively communicating risks to smokers and helping them quit successfully should be an integral part of public health programs.

Smoking remains one of the most preventable causes of death and the World Health Organization (WHO) says globally, approximately 5 million premature deaths were attributable to smoking in 2000.

The WHO says by 2030 deaths attributable to smoking will annually account for 3 million deaths in industrialized countries and 7 million in developing countries.

The study is published in the Journal of the American Medical Association.