Men with widening waistlines may be more likely to die from prostate cancer.
Specifically, a man's risk of dying from prostate cancer increases 7% for every 4-inch increase in belly fat, new research suggests.
"Our findings should encourage men to maintain a healthy weight," said study co-author Dr. Aurora Perez-Cornago, a nutritional epidemiologist at the University of Oxford in England. Exactly why carrying around extra weight makes men more likely to die from prostate cancer isn't fully understood yet.
"It is possible that some molecular disturbances in men with obesity may be causing this increased risk, but it is also possible that men with obesity have a delayed diagnosis compared with men with normal weight, and hence the tumors may be diagnosed at a more advanced stage," Perez-Cornago said.
More research is needed to determine if weight loss in obese men decreases the risk of dying from the cancer, she said.
For the study, the researchers reviewed data on 2.5 million men from 19 published studies plus a new analysis of more than 200,000 men who were part of the UK Biobank.
None of the men had prostate cancer at the start of the studies. Weight was assessed via body mass index (BMI, an estimate of fat based on weight and height), waist circumference, waist-to-hip ratio, and/or body fat percentage.
The risk of dying from prostate cancer rose along with increases in all of these measures, and every five-point increase in BMI resulted in a 10% increase in the risk of dying from prostate cancer, the study showed.
What's more, a 5% rise in total body fat percentage raised the risk of dying from prostate cancer by 3%, and each 0.05 increase in waist-to-hip ratio upped the risk of dying from prostate cancer by 6%, the investigators found.
The findings were presented this week at the European Congress on Obesity in Maastricht, the Netherlands, and published online May 5 in BMC Medicine.
These results are another reason for men who are overweight or obese to slim down, according to experts not affiliated with the new study.
"The meta-analysis presented in this publication is consistent with several other prospective analyses supporting obesity and central adiposity as a risk factor for prostate cancer incidence and death," said Dr. Andrew Laccetti, a medical oncologist at Memorial Sloan Kettering Cancer Center in Montvale, N.J.
Current research suggests hormonal and inflammatory changes may contribute to prostate cancer development, Laccetti said.
"Elevated estradiol to testosterone ratio, a hormonal change observed in men with increased waist circumference, is also thought to result in lower prostate-specific antigen (PSA) levels, which may delay prostate cancer detection, leading to diagnosis at more advanced stages," he added.
Elevated blood levels of PSA can signal the presence of prostate cancer.
"This is a well-done study that reinforces what I tell my patients: Try to lose weight if you are overweight or obese," agreed Dr. Stephen Freedland. He directs the Center for Integrated Research in Cancer and Lifestyle at Cedars-Sinai in Los Angeles. It's also important to talk to your doctor about when to screen for prostate cancer so you can catch it early when it is in its most treatable stage, Freedland said.
Learn how to prevent prostate cancer at the American Cancer Society.
SOURCES: Aurora Perez-Cornago, PhD, nutritional epidemiologist, University of Oxford, England; Andrew Laccetti, MD, medical oncologist, Memorial Sloan Kettering Cancer Center, Montvale, N.J.; Stephen Freedland, MD, director, Center for Integrated Research in Cancer and Lifestyle, Cedars-Sinai, Los Angeles; European Congress on Obesity, Maastricht, the Netherlands, May 4 to 7 2022; BMC Medicine, May 5, 2022, online