A healthy diet, normal body weight, physical activity, and not smoking may lower risk of aggressive prostate cancers, suggests a new study published in the Journal of the National Cancer Institute. Vigorous physical activity and low intake of processed meat were individually associated with decreased risk.
Previous research has given conflicting findings related to how lifestyle factors link to prostate cancer risk. This may be due to the form of prostate tumors: the majority of prostate cancers are slow-growing and do not metastasize; others are aggressive, carrying the risk of metastases and death. The study provides additional insights into prevention of this lethal form of prostate cancer.
The study started by developing a lifestyle score using data from 42,701 men in the Health Professionals Follow-up Study (HPFS) followed from 1986 to 2010. The men were ages 40 to 75 and cancer-free when they joined the study. One point was given for each of the following: BMI less than the obese category, high vigorous physical activity, not smoking or quitting smoking 10 or more years ago, high intake of tomatoes or fatty fish and low intake of processed meat.
Similar categories were used to assess diet and lifestyle among approximately half as many participants from a different group of men who were part of the Physicians’ Health Study (PHS).
Analysis of lifestyle score and lethal prostate cancer adjusted for race, diabetes, and multivitamin and vitamin E use. Analysis of diet score adjusted for BMI, smoking, and physical activity.
Men from the Health Professionals group with lifestyle scores of 5-6 compared to 0-1 had a 68 percent decreased risk of lethal prostate cancer. Analyzed separately, vigorous physical activity was associated with the most decreased risk of all the factors.
For diet factors alone, men from the Health Professionals group with a score of 3 compared to none had a 46 percent decreased risk of lethal prostate cancer. Low intake of processed meat was separately associated with decreased risk.
When the PHS group was analyzed, results based on lifestyle and diet scores showed decreased risk but were not statistically significant other than for low processed meat intake.
Differences between the two study group results could be due to differences in tools used by the studies to assess lifestyle factors including different food frequency questionnaires and physical activity assessment tools, write the authors. The Physicians' Health study was also smaller with far fewer cases of lethal prostate cancer. Further research using additional prospective cohorts is needed, they conclude.
This study was funded by the Prostate Cancer Foundation, the National Institutes of Health, the National Cancer Institute, the National Health Lung and Blood Institute, and the Dana Farber Cancer Institute Mazzone Awards Program.
Source: S. A. Kenfield, J. L. Batista, J. L. Jahn, M. K. Downer, E. L. Van Blarigan, H. D. Sesso, E. L. Giovannucci, M. J. Stampfer, J. M. Chan. Development and Application of a Lifestyle Score for Prevention of Lethal Prostate Cancer. JNCI Journal of the National Cancer Institute, 2015; 108 (3): djv329.
Published on November 25, 2015