Aging prostate cancer patients have denser bones compared to those without the disease, moving scientists closer to understanding what causes it, according to a new study.

The study, from John Hopkins University School of Medicine and the National Institute on Aging (NIA), doesn’t create a link between prostate cancer and dense bones, but it does help scientists better understand what causes the disease and how it spreads.

With this study, Dr. Stacey Loeb, a resident in the Department of Urology at John Hopkins, and her colleagues expand on the long-known fact that when prostate cancers spread, or metastasize, they often affect the bone.

“We reasoned there may be some difference between men who develop prostate cancer, especially metastatic disease, and those who don’t, and it was logical to see if there was something different about their bones,” says Loeb.

Loeb’s team studied health information of 519 Baltimore-area men, collected by the NIA’s Baltimore Longitudinal Study of Aging, which is part of the National Institutes of Health and has tracked health-related information for hundreds of people from the area since 1958.

The bone density data of the 519 men, which was measured between 1973 and 1984, was then compared with data from those in the group who were later diagnosed with prostate cancer.

Loeb’s team found that 76 men eventually developed prostate cancer. When compared with participants who didn’t develop prostate cancer, those men also maintained significantly higher bone density as they aged. Furthermore, 18 of the men with the highest bone density were diagnosed with high-risk prostate cancer.

Bone density typically declines as both men and women age.

The results may indicate that bone density and the development and spread of prostate cancer share some of the same determining factors, like sex hormones and growth factors in bone. But Loeb says the study sample is too small to draw any conclusions on a potential link between the two.

“If we can elucidate the underlying pathways, we could develop strategies for preventing prostate cancer from occurring or spreading,” Loeb said.

The findings are published in the July issue of British Journal of Urology International.

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