Vigorous Exercise and Healthy Habits May Dramatically Reduce Chance of Lethal Prostate Cancer for Men Over 60
- Participants with 5 to 6 points in the health professionals’ group had a 68% decreased risk of lethal prostate cancer, and a 38% decreased risk was observed in the physicians’ group for the same comparison.
- For dietary factors alone, men with 3 points vs those with 0 points had a 46% decreased chance of developing lethal prostate cancer in the health professionals’ group. In the physicians’ group, this decrease was 30%.
- Lethal prostate cancer risk among American men over 60 would be cut by 15% if they consumed at least seven servings of tomatoes per week, by 17% if they consumed at least one serving of fatty fish per week, by 12% if they reduced processed meat intake, and by 3% by not smoking.
A study that tracked tens of thousands of middle-aged and older men for more than 20 years has found that vigorous exercise and other healthy lifestyle habits may cut their chances of developing a lethal type of prostate cancer by up to 68%.
While most prostate cancers are clinically indolent, a minority of patients are diagnosed with aggressive disease that invades the bone and other organs, and is ultimately fatal. Stacey Kenfield, ScD, of the University of California, San Francisco (UCSF), and a team of researchers at UCSF and Harvard, focused on this variant of prostate cancer to determine if exercise, diet, and smoke-free status might have life-saving benefits.
In the study, published by Kenfield et al in the Journal of the National Cancer Institute, the researchers analyzed data from two American studies: the Health Professionals Follow-Up Study, which tracked more than 42,000 males aged 40 to 75 from 1986 to 2010; and a second, the Physicians’ Health Study, which followed more than 20,000 males aged 40 to 84 from 1982 to 2010.
To gauge the effects of lifestyle habits, the researchers developed a score based on the results of the health professionals survey and then applied it to the physicians’ study. They assigned 1 point for each affirmative response to questions about regular intense exercise that induced sweating, body mass index (BMI) under 30, tobacco-free status for a minimum of 10 years, high intake of fatty fish, high intake of tomatoes, and low intake of processed meat.
To reduce error, participants had to be free of diagnosed cancer at the start of the study, and a 4-year lag was imposed to rule out those who unknowingly had lethal prostate cancer, which was determined by evidence of “prostate cancer death or metastasis to the bones or other organs, excluding the lymph nodes.” Cases were confirmed through medical records and pathology reports, and cause of death was determined primarily by death certificate and medical record, and secondarily by next of kin.
The researchers identified 576 cases of lethal prostate cancer in the health professionals’ group and 337 cases in the physicians’ group. Participants with 5 to 6 points in the health professionals’ group had a 68% decreased risk of lethal prostate cancer, and a 38% decreased risk was observed in the physicians’ group for the same comparison.
For dietary factors alone, men with 3 points vs those with 0 points had a 46% decreased chance of developing lethal prostate cancer in the health professionals’ group. In the physicians’ group, this decrease was 30%.
While there were fewer cases and less detailed data collected in the physicians’ study, the score was similar in both populations, indicating the potential benefit of healthy lifestyle habits in warding off lethal prostate cancer, said the authors.
“We estimated that 47% of lethal prostate cancer cases would be prevented in the United States if men over 60 had five or more of these healthy habits,” said Dr. Kenfield, Assistant Professor in the Department of Urology at UCSF Medical Center and formerly of the Department of Medicine at Harvard Medical School in Boston, where the study was initiated.
“It’s interesting that vigorous activity had the highest potential impact on prevention of lethal prostate cancer. We calculated the population-attributable risk for American men over 60 and estimated that 34% of lethal prostate cancer would be reduced if all men exercised to the point of sweating for at least 3 hours a week,” Dr. Kenfield said.
The researchers also calculated that lethal prostate cancer among American men over 60 would be cut by 15% if they consumed at least seven servings of tomatoes per week and that 17% would be spared this diagnosis if they consumed at least one serving of fatty fish per week. Reducing intake of processed meats would cut the risk by 12%, they reported. In contrast, the population-attributed risk for smoking was 3%, largely because the majority of older American men are long-term nonsmokers.
“This study underscores the ongoing need for more effective prevention measures and policies to increase exercise, improve diet quality, and reduce tobacco use in our population,” said June M. Chan, ScD, from the Departments of Urology and Epidemiology & Biostatistics at UCSF. “It takes cooperation and effort from multiple areas, like insurance companies, employers, policymakers, and city planners, to figure out how to creatively support and encourage more exercise into most busy adults’ working day. These lifestyle habits align with other recommendations to prevent diabetes and heart disease.”