The study dispels the notion that so-called "light" smokers aren't threatened by the serious health problems faced by heavy smokers.

Heart Disease, Lung Cancer

Reporting in the current issue of Tobacco Control, researchers analyzed health and mortality data on nearly 43,000 men and women collected from the mid 1970s until 2002. All the people were between 35 and 49 years of age at the start of the study.

Compared with people who'd never smoked, those who smoked one to four cigarettes a day were nearly three times as likely to die of heart disease.

Men who were light smokers were nearly three times as likely to die of lung cancer, while women who were light smokers were nearly five times as likely to be killed by lung cancer, compared with non-smokers.

The study also found that light smokers were at a 50 percent higher death rate from all causes than people who'd never smoked.

No Safe Level

The American Cancer Society applauded the research.

Thomas J. Glynn, the ACS director of cancer science and trends and international tobacco programs, said in a prepared statement, "The finding that smoking just 1 to 4 cigarettes a day can significantly boost heart disease and cancer rates is important because many smokers, due to expanding restrictions on smoking in public places and at work, are cutting back on the number of cigarettes they smoke each day.

"By doing so, they often feel that they are sharply reducing or eliminating the health dangers from smoking. But this study shows that this is not the case and reiterates the important message that there is no such thing as a safe level of smoking."

More information: The American Cancer Society has more about smoking and health.