Asthmatics have less risk of fatal prostate cancer, Johns Hopkins research suggests

Men with a history of asthma appear to be less likely to develop lethal prostate cancer, Johns Hopkins researchers found in a recent study.

The study, published in The International Journal of Cancer, presents an interesting contradiction to past research linking prostate cancer with the type of inflammation found with asthma. The new study discovered that males with a history of asthma were 29 percent less likely to be diagnosed with prostate cancer that spread or became fatal. Overall, asthmatic men were 36 percent less likely to die of the disease.

But it's too early to conclude that asthma may in some way protect men from prostate cancer, cautions Elizabeth A. Platz, co-leader of the Cancer Prevention and Control Program at the John Hopkins Kimmel Cancer Center.

"We don't know yet whether the association we see in this observational study is a case of cause and effect," says Platz, who is also a professor of epidemiology at JHU's Bloomberg School of Public Health.

The researchers launched thier investigation based on past studies linking prostate cancer with an immune response known as Th2 inflammation, which is found with asthma.

"Cancer is often thought of as mediated by Th2 inflammation. So what we expected was that asthmatics would have a higher incidence of prostate cancer," says [Charles Drake] (, co-director of the Prostate Cancer Multidisciplinary Clinic at the Kimmel Cancer Center. Instead, he says, the new study "showed the exact opposite."

The study followed 47,880 men ages 40 to 75, who filled out questionnaires on their health every two years from 1986 through 2012. Within this group, there were 798 confirmed deaths due to prostate cancer. For all those diagnosed with the disease, researchers dug into their medical background.

In asthmatics, the research found lower risks of prostate cancer even when other factors were considered, such as medications or the stage of life when asthma was diagnosed.

The study also tracked men with hay fever and found a different (though less conspicuous) association: That category turned out to be 10 to 12 percent more likely to develop fatal prostate cancer.

Drake, an immunologist, and Platz, an epidemiologist, aim to continue the research with their other collaborators. They plan to "go back to the lab and try to characterize the nature of the immune cells present in the prostate," Platz says, to determine whether certain immune profiles or environments might be related to prostate cancer.

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