People who give up smoking begin to improve their health almost immediately, according to a study of more than 100 000 women carried out between 1980 and 2004. Within five years the risk of death from all causes fell by 13%, it found. After 20 years, people had no extra risk of death because of their past smoking history.
The study, by researchers at Harvard medical school in Boston, also highlights the benefits of not starting smoking until later; women who began at 17 were 22% more likely to die within the study period than those who started at 26 or older. The news will encourage the third of smokers in the United Kingdom who would like to give up the habit. A survey by the UK’s Office for National Statistics, released in January, found 22% of Britons are smokers, down from 27% at the end of the 1990s and the lowest level since records began.
According to the British Medical Association, smoking-related illnesses kill more than 90 000 people each year, and cost the UK health service £1,5-billion per year.
The new study used data from the so-called Nurses Health Study in the United States, which collected health questionnaires from more than 120 000 women aged between 30 and 55 in 11 states from 1976 onwards. Researchers could link answers to lifestyle questions — for example, about how much they smoked — to information about the volunteers’ general health and how they ended up dying. The questionnaires have been repeated every two years, giving researchers an evolving picture of the participants’ habits and lives. From this they were able to compare women who had smoked but given up, with women who had never smoked or never given up.
The study confirmed that smoking is a potent cause of disease; 64% of deaths among current smokers could be attributed 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. They also raised their risk of lung cancer by 40 times.
More heartening for smokers who want to kick the habit are data suggesting that 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%.
Rates of mortality from respiratory disease, lung cancer and smoking-related cancer were all lower in women who had started smoking later. “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,” the authors of the study, Dr Stacey Kenfield and colleagues, wrote in the Journal of the American Medical Association. —