Men who are tall and obese are at increased risk of high grade prostate cancer and prostate cancer death, according to a study published in the open access journal BMC Medicine.

A research team led by the University of Oxford, UK found that while height was not associated with overall prostate cancer risk, risk of high grade disease and death from prostate cancer increased by 21% and 17% respectively with every additional ten centimetres (3.9 inches) of height.

Higher BMI was also found to be associated with increased risk of high grade tumours, as well as increased risk of death from prostate cancer.

Waist circumference, which is seen as a more accurate measure of obesity than BMI in older adults, was associated with an 18% greater risk of death from prostate cancer and a 13% greater risk of high grade cancer with every ten centimetres (3.9 inches) increase in waist circumference.

Dr Aurora Perez-Cornago, the lead author said: "The finding of high risk in taller men may provide insights into the mechanisms underlying prostate cancer development, for example related to early nutrition and growth. We also found that a healthy body weight is associated with a reduced risk of high grade prostate cancer and death from prostate cancer years later. The observed links with obesity may be due to changes in hormone levels in obese men, which in turn may increase the risk of aggressive prostate cancer. However, the difference in prostate cancer may also be partly due to differences in prostate cancer detection in men with obesity. "

The study is among the first to differentiate between high grade and advanced stage tumours while investigating the links between height and obesity and prostate cancer.

Most previous research did not group tumours into subtypes according to how far the tumour had spread (stage) and how abnormal tumour cells were when compared to normal cells (grade).

Instead, stage and grade were grouped together in combined categories of aggressive or non-aggressive tumours.

Dr Perez-Cornago said: "Our data illustrate the complex association of adiposity and prostate cancer, which varies by disease aggressiveness. These results emphasise the importance of studying risks for prostate cancer separately by stage and grade of tumour. They may also inform strategies for prevention, but we need to do further work to understand why the differences in risk exist."

The researchers used data from the European Prospective Investigation into Cancer and Nutrition (EPIC), a prospective European cohort of 141,896 men, collected in eight countries - Denmark, Italy, the Netherlands, Spain, Sweden, the UK, Germany and Greece.

The data included 7,024 incident prostate cancers, 726 high-grade and 1,388 advanced stage prostate cancers, and 934 prostate cancer deaths.

The authors caution that in older adults such as the participants in this study, who were on average 52 years or older, BMI as a measure of overweight and obesity may be less sensitive than in younger cohorts.

This may have led to an underestimate of the prevalence of obesity.

Nonetheless, waist circumference, which is seen as a more accurate measure of obesity than BMI in older adults, was associated with a greater risk of prostate cancer death and high grade disease.

Further work is needed to understand whether the higher risk of aggressive prostate cancer in men with obesity is due to an increased risk of developing aggressive forms of the disease or to differences in prostate cancer detection.

Source: BioMed Central