Britain: Smoking only a few cigarettes a day almost triples the risk of heart disease and lung cancer, researchers said yesterday.
The impact of "light smoking" - between one and four cigarettes a day - is even stronger in women, according to the study published in Tobacco Control.
The findings quash the notion that "light" smokers escape the serious health problems faced by those who are heavy smokers.
The research was carried out by Dr Aage Tverdal, from the Norwegian Institute of Public Health, and Dr Kjell Bjartveit, from the National Health Screening Service in Oslo.
They tracked the health and death rates among almost 43,000 men and women in Norway from the mid-1970s up until 2002.
At the start of the study all those taking part were aged 35 to 49 and were screened for cardiovascular disease and diabetes.
Taking into account other risk factors, the researchers were able to conclude that light smoking did significantly endanger health.
People who smoked between one and five cigarettes a day were almost three times more likely to die from coronary artery disease than those who had never smoked.
Men who were light smokers were almost three times more likely to be killed by lung cancer, while women were almost five times as likely to die of the disease as their non-smoking peers.
Researchers also found that light smokers had significantly higher death rates from all causes - up by 1½ times - compared to people who had never smoked.
Death rates were also linked to the number of cigarettes smoked each day.
The researchers concluded: "In men and women smoking one to four cigarettes per day, there was a distinct increase in risk of death from ischaemic heart disease and from all causes. For ischaemic heart disease, the steepest increase was in both sexes between zero and one to four cigarettes per day. Above this level, the slope was less pronounced."
The researchers said many people in the past had assumed a few cigarettes a day were not harmful to health. But they said research had now shown this was not the case. - (PA)