Bladder cancers: one in four due to jobs.

Bladder cancers: One in four due to jobs

Male boothblacks, salespeople, broadcasters, gardeners, and produce graders or packers are among a host of workers running an increased, previously unrecognized risk of bladder cancer, according to a pair of government studies. Past studies have shown that smoking may account for half of male bladder cancers. Jobs now appear responsible for half the rest, the new studies reveal.

Striking roughly four times as many men as women in the United States, carcinoma of the urinary bladder is the fifth most common cancer in men.

Epidemiologists with the National Cancer Institute in Bethesda, Md., and the Walter Reed Army Institute of Research in Washington, D.C., polled 2,100 white and 126 nonwhile men with bladder cancer -- from 10 geographically diverse areas -- for data on every job they had held for six months or longer since age 12. The researchers compared these data with those collected from almost twice as many randomly selected men of the same races and about the same ages.

At least some of the observed associations between jobs and cancer are "virtually certain" to have resulted from chance, Debra T. Silverman and her coauthors note in the Oct. JOURNAL OF THE NATIONAL CANCER INSTITUTE. For example, they say, though male clerical work has been linked with risk of the cancer in two other studies -- and here in a threefold excess after 10 years of employment -- scientists have "no credible biologic explanation" for such a link.

However, weighing the magnitude of apparent risk along with its statistical significance and several other factors, the researchers now conclude that "the strongest evidence of increased risk" in white men shows up in painters (exposed to many known and potential carcinogens), truck drivers (exposed to carcinogens in vehicular exhaust) and drill press operators (exposed to potentially toxic cutting- and lubricating-oil mists.)

Painters, for example, initially face a risk 50 percent greater than that of men who have never painted, according to the new results. And painters employed 10 years or more run a risk 300 percent higher than nonpainters. Ironically, the scientists say, though nine other studies have suggested a similar association, the risk of bladder cancer among painters "has received little attention."

Risks that stand out among nonwhites, whom the researchers studied separately, include employment at any time within the auto industry or as dry cleaners or clothes pressers. However, the researchers note, the overall "risk of occupational bladder cancer among white and nonwhite men is similar."