A new study published in the Journal of the American Medical Association shows that women who quit smoking see significant health benefits within 5 years of their last cigarette. However, it can take up to 20 years or more for their risk of death to drop to the level of those who never smoked.

According to the study, women who smoke were more than 20 times more likely to die of lung cancer than those who didn't smoke. The study also showed that former smokers were about 5 times more likely to die from it. The study also showed that lung cancer was not the only type of cancer that had increased occurrences in smokers. Increases in colorectal cancer were also noted in the study. However, no increased risk of ovarian cancer was found in the study.

The study also showed that cancer was not the only disease that saw increased rates among smokers. Heart disease, stroke and COPD (bronchitis and emphysema) also showed increases among smokers.

The study, called the Nurses' Health Study, began in 1976, with 117,988 registered nurses between the age of 30 and 55 filling out a questionnaire detailing their medical history. The study was then updated and expanded every 2 years. The results of this study present one of the clearest pictures of both the risks of smoking and the benefits of quitting.