Abdominal obesity appears to be associated with a greater risk of developing aggressive prostate cancer (PCa), according to a study, ‘General and abdominal obesity trajectories across adulthood, and risk of prostate cancer: results from the PROtEuS study, Montreal, Canada,’ led by Professor Marie-Élise Parent of Institut national de la recherche scientifique (INRS) and published in the journal Cancer Causes & Control.
Previous studies have shown that obesity is a major risk factor for prostate cancer and to explore the link between disease incidence and body mass, the research team studied data from a survey conducted in Montréal between 2005 and 2012. Researchers observed that abdominal obesity was associated with an increased risk of aggressive cancer.
"Pinpointing the risk factors for aggressive cancer is a big step forward in health research because it's the hardest to treat," said Parent. "This data creates an opportunity to work preventively, by monitoring men with this risk factor more closely.”
The actual distribution of body fat appears to be a significant factor in the development of the disease: the impact on a person's health can vary depending on whether the fat is concentrated around the abdomen or distributed throughout the body.
"Abdominal obesity causes hormonal and metabolic variations that can promote the growth of hormone-dependent cancer cells,” said Éric Vallières, a Université de Montréal student conducting his doctoral research at INRS and the study's main author. “Abdominal obesity is believed to be associated with a decrease in testosterone, as well as a state of chronic inflammation linked to the development of aggressive tumours."
Subjects with a current BMI ≥ 30 kg/m2 had a lower risk of overall PCa (OR 0.71, 95% CI 0.59–0.85). Associations with adult BMI followed similar trends for less and more aggressive tumours, with stronger inverse relationships in early adulthood. Contrastingly, current waist circumference ≥ 102 cm was associated with elevated risk of high-grade PCa (OR 1.33, 95% CI 1.03–1.71). Men with increasing BMI or waist circumference adult trajectories had a lower risk of PCa, especially low-grade, than those in the normal-stable range. This was especially evident among men in the obese-increase group for BMI and waist circumference.
The study showed that general obesity did not show the same correlation as abdominal fat., however, the researchers added that his may result from a detection bias and possible biological effects.
"In people with obesity, the protein used to detect prostate cancer at an early stage, prostate-specific antigen (PSA), is diluted in the blood," Vallières added. "This haemodilution makes cancer more difficult to detect."
The research team believes that studies on the timing of obesity exposure over a lifetime should be prioritised, and that a more in-depth analysis of body fat distribution could provide greater insight into the risks of developing prostate cancer.