Almost Half of Bladder Cancers Caused by Smoking

Smoking cigarettes is a significant risk factor for developing bladder cancer, according to a study that found almost half of these cancers are caused by smoking.

Researchers from the National Cancer Institute found smokers are four times more likely to develop bladder cancer, compared with someone who has never smoked. That rate has risen from a threefold increased risk 30 years ago, HealthDay reports.

In the Journal of the American Medical Association, the researchers report smokers who have quit are still 2.2 times more likely than someone who has never smoked to develop bladder cancer.

More than 70,000 people in the United States are diagnosed with bladder cancer every year, according to the journal’s news release. The researchers say the link between cigarette smoking and bladder cancer may be due in part to changes in the constituents of cigarette smoke, which has led to an apparent increase in the concentration of specific carcinogens.

The study found the risk of bladder cancer tends to rise along with the number of cigarettes a person smokes.