Bone density linked to prostate cancer risk

Though the most aggressive prostate cancers are known to afflict bones too, the connection between bone characteristics, prostate cancer development, and its metastasis was still unclear.

“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,” study’s lead researcher, Stacy Loeb, a resident in the Department of Urology at the Johns Hopkins University School of Medicine said.

Details of the study
To determine if bone quality played a role in prostate cancer spread, Loeb and her colleagues picked up data of 519 men enrolled in the NIA’s Baltimore Longitudinal Study of Aging.

Information about their bone-mineral-density, measured using a single photon absorptiometry, was specifically used for the study. The samples were collected between 1973 and 1984.

Generally, bone density declines with age in both men and women.

However, a total of 76 men were found to have a considerably higher bone density as compared to other participants of the same age. These men went on to develop prostate cancer, researchers found.

Further examination showed that 18 men with the most aggressive and dangerous forms of prostate cancer were the ones who recorded the highest bone density, Loeb said.

In contrast, men without prostate cancer showed a gradual decline in bone mineral density as they aged.

The findings came out significant even after making adjustments for lifestyle factors known to influence bone density, such as smoking, body mass index, and intake of calcium and vitamin D supplements.

Interpreting results with caution
While the results of the study establish the link between bone density and prostate cancer risk, the findings are based on an evaluation of a relatively small number of patients, thus results should be interpreted with caution, researchers say.

"Clearly, additional study is warranted to clarify the factors within bone that enhance prostate cancer progression," Loeb and colleagues concluded.

Also, as the study subjects were primarily white, the findings cannot be generalized to other racial groups, the researchers noted.

The findings of the study feature in the July issue of British Journal of Urology International.