| Cigarette
smoking is an important risk factor for bladder cancer in postmenopausal
women Cigarette smoking is an important risk factor in bladder cancer in postmenopausal women, a group that until now has received little attention in the study of this cancer, according to an article in the December print issue of CANCER (available online since November 15th). Dr. Tripathi and her American colleagues conducted a prospective study of 37,459 women between the ages of 55 and 69 years who completed baseline questionnaires in 1986. They were followed for 13 years to determine incidence of bladder cancer. Baseline data included demography, past medical and cancer history, past and current smoking and alcohol consumption, physical activity, marital status, waist-to-hip ratio, and body mass index. Follow-up questionnaires were sent in 1987, 1989, 1992 and 1997, and new cases of bladder cancer were cross-matched with data from a state registry. By 1998, 112 women were identified with bladder cancer. Smoking was identified as the most significant risk factor for bladder cancer in postmenopausal women. Current smokers were 4.23 times more likely than women who never smoked to be diagnosed with bladder cancer (after multivariable adjustment). The relative risk increased as the number of pack-years (a measure of cumulative smoking exposure) increased. Smoking cessation curbed increased risk: Bladder cancer incidence decreased with time after smoking cessation. After 15 years since quitting smoking, the incidence rate approached that of women who never smoked. The authors' analysis further shows that "approximately 25% of bladder carcinoma incident cases in our study population might be attributed to ever smoking." Other potential risk factors identified after multivariable analysis were diabetes, physical inactivity, and marital status. Diabetics had a 2.46-fold greater relative risk of bladder cancer than nondiabetics. Regular physical activity was also protective compared with no physical activity, with a relative risk of 0.66. However, there was no difference between moderate to high levels of physical activity. Married women had a lower incidence rate and a relative risk of only 0.66 compared with unmarried women. Alcohol, occupation, and caffeine were not associated with altered risk for bladder cancer. The authors concluded "We confirmed that
cigarette smoking is an important risk factor for bladder cancer
in women: women who had quit smoking had a reduction of risk"
and "also identified diabetes and lifestyle factors such as
reduced physical activity as potential risk factors." |