Specific lifestyle factors, like engaging in vigorous physical activity, maintaining a healthy body weight, not smoking, and eating plenty of fatty fish, may reduce the risk of developing prostate cancer, researchers reported. The study, published in the Journal of the National Cancer Institute, is titled “Development and Application of a Lifestyle Score for Prevention of Lethal Prostate Cancer.”
Prostate cancer is the most frequently diagnosed cancer and the second leading cause of cancer deaths among men in the United States. Most prostate cancer patients are diagnosed with clinically indolent tumors without lethal potential, but several lifestyle factors have been associated with more deadly forms of the disease.
To develop and apply a lifestyle score of activities that lower such a risk, Stacey A. Kenfield, from the University of California San Francisco, and colleagues analyzed data from the Health Professionals Follow-up Study (HPFS) and the Physicians’ Health Study (PHS).
The team developed its score among 42,701 men in the HPFS group and applied it among 20,324 men in the PHS group. One point was given for each key activity: currently not smoking or having quit 10 or more years ago, body mass index under 30kg/m2, high vigorous physical activity, high intake of tomatoes and fatty fish, and low intake of processed meat.
The analysis included a calculation of diet-only scores (range = 0–3) and total scores (range = 0–6). A multivariable Cox proportional hazards regression was used to estimate the risk of lethal prostate cancer, adjusting for potential risk factors of such cancer.
Among men in both groups, 913 lethal prostate cancer events (576 from HPFS and 337 from PHS) were identified.
In the HPFS group, results showed that men with a score of either 5 or 6 had a 68 percent lower risk of lethal prostate cancer than men with a score of 0 or 1. A one-point increase in the score was linked with a 20 percent decrease in risk.
In the PHS group, men with a score of either 5 or 6 had a 32 percent lower risk than those with a score of 0 or 1, however these differences were not significant.
When the analysis was performed taking into account only dietary factors, the results revealed that men in the HPFS group who had a score of 3 had a 46 percent decreased risk than men with a score of 0. A one-point score increase was linked with a 19 percent decreased risk.
In the PHS group, the results revealed that men with a score of 3 had a 30 percent lower risk than men with a score of 0, but, again, this difference was not significant.
“We estimated that 47 percent of lethal prostate cancer cases would be prevented in the United States if men over 60 had five or more of these healthy habits,” Kenfield said in a press release. “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 percent of lethal prostate cancer would be reduced if all men exercised to the point of sweating for at least 3 hours a week.”
If men 60 and older consumed at least seven weekly servings of tomatoes, their incidence of deadly prostate cancer would decrease by 15 percent, and by 17 percent if they had one weekly serving of fatty fish (fish high in omega-3 fatty acids, like salmon, tuna, sardines and trout).
Less than three weekly servings of processed meat would signify a 12 percent lower risk.
“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,” June M. Chan, a professor of epidemiology and biostatistics and a professor of urology at University of California, San Francisco, said in a press release. “It takes cooperation and effort from multiple areas ― like insurance companies, employers, policy makers 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.”