Smoking just one to four cigarettes a day almost triples the risk of dying of heart disease, according to Norwegian researchers.
In a latest research, quoted by BBC, they suggest the health impact is stronger for women and that even "light" smokers face similar diseases to heavier smokers, including cancer.
Among women, smoking one to four cigarettes daily increased the chance of dying from lung cancer almost five times. Men who smoked this amount were almost three times as likely to be killed by lung cancer.
Compared with those who had never smoked, the men and women who smoked between one and four cigarettes a day were almost three times as likely to die of coronary artery disease.
The team tracked the health and death rates of almost 43,000 men and women from the mid 1970s up to 2002. Their findings appear in the journal Tobacco Control.