In the United States, prostate cancer is the second most common cancer in men. Around 1 in 7 men will be diagnosed with prostate cancer in their lifetime, with 1 in 39 men estimated to die from the disease.

As with other types of cancer, treatments are available, but there are also a great number of questions still to answer about risk factors and disease progression.

Recently, a group of researchers from the University of Oxford in the United Kingdom decided to look at the relationship between height, obesity, and prostate cancer grade.

Size, prostate cancer, and risk

Previous research looking at the relationship between height, body mass index (BMI), and prostate cancer risk has produced varied results. Some early studies demonstrated an increased risk with BMI but not height, while others were inconclusive for both weight and height.

However, much of the earlier work did not split the data into cancer type. For instance, they did not take into account the stage (how far the tumor has spread) and the grade (how abnormal the tumor cells are). This U.K. research project is one of the first to differentiate between high-grade and advanced stage tumors.

Lead author Dr. Aurora Perez-Cornago and her team reopen the debate and take a fresh look at the relationship in more granular detail.

Data were taken from the European Prospective Investigation into Cancer and Nutrition, comprising 141,896 men from Denmark, Italy, Germany, Greece, the Netherlands, Spain, Sweden, and the U.K. The average age of the participants was 52.

In all, there were 7,024 incidences of prostate cancer, of which 726 were high-grade and 1,388 were in an advanced stage. There were also 934 deaths caused by prostate cancer.

Once the data had been analyzed, the team concluded that height was not linked with overall prostate cancer risk.

However, risk of high-grade disease and death from prostate cancer was linked to height: risk increased by 21 percent and 17 percent, respectively, with each additional 10 centimeters in height.

Why height might be a factor in prostate cancer is unclear. Dr. Perez-Cornago says, "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."

Links with BMI and waist measurement

The team also noted a relationship between BMI and prostate cancer: higher BMIs were associated with a higher risk of high-grade tumors, as well as an increased risk of death from prostate cancer.

In older men, waist circumference is considered a better way to measure obesity than BMI, and this measure was matched with an 18 percent higher risk of death from prostate cancer, as well as a 13 percent higher risk of high-grade cancer, with every 10 additional centimeters in waist circumference.

The researchers believe that understanding why weight is linked to prostate cancer may take some time to unpick.

"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." Dr. Aurora Perez-Cornago

At the other end of the scale, a healthy weight was shown to have the opposite effect. Dr. Perez-Cornago explains that "a healthy body weight is associated with a reduced risk of high-grade prostate cancer and death from prostate cancer years later."

Although these findings are fascinating, it will be some time before the exact mechanisms behind them are uncovered. "These results emphasize the importance of studying risks for prostate cancer separately by stage and grade of tumor," Dr. Perez-Cornago explains.

"They may also inform strategies for prevention, but we need to do further work to understand why the differences in risk exist."