According to the American Cancer Society’s 2016 Cancer Facts & Figures, behaviors such as poor diet choices, physical inactivity, excess alcohol consumption, and unhealthy body weight account for about 20% of all cancers diagnosed in the United States and likely could be prevented with lifestyle modifications. Now, a systematic review of 12 prospective cohort studies examining the association between adherence to the American Cancer Society and the World Cancer Research Fund/American Institute for Cancer Research nutrition and physical activity cancer prevention guidelines and the risk of overall cancer incidence and mortality has found that following the guidelines was associated with a 10% to 45% reduction in all-cancer incidence and a 14% to 61% reduction in all-cancer mortality. The study also found consistent reductions in the incidence of breast, endometrial, and colorectal cancers. These findings by Lindsay N. Kohler, MPH, of the University of Arizona Mel and Enid Zuckerman College of Public Health in Tucson, and colleagues were published in Cancer Epidemiology, Biomarkers & Prevention.
The researchers searched the databases of PubMed, Google Scholar, and Cochrane Reviews to identify prospective cohort studies that examined associations between adherence to nutrition and physical activity cancer prevention guidelines and cancer incidence and mortality following the recommendations of Preferred Reporting Items for Systematic Reviews and Meta-analysis Approach (PRISMA). Twelve studies met inclusion criteria for their review. Only prospective cohort studies were eligible for inclusion. Although overall cancer incidence and cancer mortality were the primary outcomes of interest, the researchers also considered site-specific cancer risks when data were available from at least two studies meeting the eligibility criteria.
The 12 studies reviewed represented analyses of data from 10 cohorts, including the Cancer Prevention Study-II nutrition cohort, the Women’s Health Initiative cohort, the NIH-American Association of Retired Persons Diet and Health Study cohort, the Framingham Offspring cohort, the Vitamins and Lifestyle Study cohort, the Canadian National Breast Screening Study, the Swedish Mammography Cohort, the European Prospective Investigation Into Cancer and Nutrition cohort, the Southern Community Cohort Study, and the Iowa Women’s Health Study cohort.
High vs low adherence to established nutrition and physical activity cancer prevention guidelines was consistently and significantly associated with decreases of 10% to 61% in overall cancer incidence and mortality. Consistent significant reductions were also shown for breast cancer incidence (19%–60%), endometrial cancer incidence (23%–60%), and colorectal cancer incidence in both men and women (27%–52%). Findings for lung cancer incidence were equivocal, and no significant relationships were found between adherence and ovarian or prostate cancer.
“Adhering to cancer prevention guidelines for diet and physical activity is consistently associated with lower risks of overall cancer incidence and mortality, including for some site-specific cancers,” concluded the study authors.
In a statement about the study’s findings, Ms. Kohler, who is the lead author of the study, said that the review indicates physicians and public health officials should continue to advocate the use of cancer prevention recommendations to their patients. “If you adhere to these guidelines, you may reduce your risk of getting or dying from cancer, though the risk is not totally eliminated. However, following these recommendations will lead to healthier lives overall and, in turn, reduce the risk for many major diseases,” she said. ■