Men measuring 5 feet 9 inches and taller are more likely to be diagnosed with a more aggressive form of prostate cancer, according to researchers.

Janet Stanford, a researcher at the University of Washington School of Public Health and the Fred Hutchinson Cancer Research Center, collaborated with a team of international researchers to investigate the effects of height on prostate cancer risk. The findings were published August 1 in the British Journal of Cancer.

Prostate cancer is the most common cancer in men in the United States and second-most common worldwide. Studies over the years have established age, ethnicity, family history and more than 100 common genetic variants as risk factors for the cancer. Height as a risk factor has been less conclusive, though more recent studies have suggested a possible role in high grade, or more aggressive, prostate cancer.

In this study, Stanford and her collaborators looked at more than 6,200 prostate cancer cases and 6,000 controls provided by the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome (PRACTICAL) Consortium to examine the relationship of height with prostate cancer risk through three steps.

First, Stanford and other PRACTICAL researchers explored the relationship of height with risk of overall prostate cancer and risk of high-grade (Gleason score of 7 – 10) prostate cancer. Next, they looked at genetic variations, or polymorphisms, in genes related to height. Finally, they analyzed their findings to determine whether there was any interaction between genetic polymorphisms and height.

The findings from the study concluded that height is not associated with overall prostate cancer risk, but taller men had a 22 percent higher risk of having high-grade (more aggressive) cancer compared to those who were shorter (5 feet 6 inches and below).

“Because of the large size of the study, it provides stronger evidence for a role of height as an indicator of growth-related factors in the development of higher grade prostate cancer,” said Stanford, a research professor in the department of epidemiology. “The current study had more power to examine this association compared to earlier, smaller studies that were limited in the number of high-grade cases available for analysis.”

Established in 2008, the PRACTICAL Consortium is funded by Cancer Research UK and composed of 78 study groups around the world. The group receives data from the Collaborative Oncology Gene-environment Study (COGS), a project funded by the European Commission and 7th Framework Programme and the National Institutes of Health grant. Stanford has been a member of the Consortium since 2009.

“This is really one of the first analyses from the PRACTICAL Consortium that put together epidemiologic data with results from the COGS genotyping effort,” said Stanford. “None of this would be possible without the combined efforts of investigators from all around the world. Collaboration is what makes this type of work possible.”