By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - I am not breaking any new medical ground when I tell you that smoking can increase the risk of heart attack and stroke, but the more we study the risks and look at specific groups, the greater the concerns we see.

The latest information is from a study of women which found that even light to moderate smokers may be more likely to suffer sudden cardiac death.

Sudden cardiac death leads to the demise of 300,000-400,000 people each year in the United States. Essentially, this is a major loss of heart function without any warning.

According to the study, women who smoked 14 cigarettes per day have a two and a half times greater risk than when compared to women who do not smoke.

Another way of looking at it, for every five years of smoking the risk goes up eight percent. If a woman quits, it takes 15 years to get back to the risk of a non-smoker