Washington, August 17: A study by scientists from the National Cancer Institute (NCI), part of the National Institutes of Health, has found that current cigarette smokers have a higher risk of bladder cancer than previously reported, and the risk in women is now comparable to that in men.

While previous studies showed that only 20 to 30 percent of bladder cancer cases in women were caused by smoking, these new data had indicated that smoking is responsible for about half of female bladder cancer cases - similar to the proportion found in men in current and previous studies.

The increase in the proportion of smoking-attributable bladder cancer cases among women may be a result of the increased prevalence of smoking by women, so that men and women are about equally likely to smoke, as observed in the current study and in the U. S. population overall, according to surveillance by the CDC.

The researchers found that the amount of risk brought on by smoking, called excess risk, was higher in this study than in previously reported.

"Current smokers in our study had a fourfold excess risk of developing bladder cancer, compared to a threefold excess risk in previous studies. The stronger association between smoking and bladder cancer is possibly due to changes in cigarette composition or smoking habits over the years," said study author Neal Freedman, Ph. D., in NCI''s Division of Cancer Epidemiology and Genetics (DCEG).

The study has been published in the Journal of the American Medical Association. (ANI)