Lifestyle factors may reduce risk of colorectal cancer
Patients who follow specific diet and lifestyle recommendations can reduce their risk of developing colorectal cancer, according to a study published online in BMJ (2010;341:c5504).
For the study, Helene Kirkegaard, PhD, of the Danish Cancer Society in Copenhagen, Denmark, and colleagues ranked more than 55,000 people using an index that scored one point for adherence to five recommendations about physical activity, waist circumference, smoking, alcohol use, and diet. The researchers found that every additional baseline point was associated with an incidence rate ratio of 0.89 for colorectal cancer.
Results from the study also revealed that if participants followed all five of the recommendations, an estimated 23% of cancer cases could have been prevented during a median follow-up of almost 10 years.
In a second linked paper also published online in BMJ, researchers analyzed the use of a decision aid to help adults with low literacy to understand the pros and cons of bowel cancer screening. Led by Sian K. Smith, BSc, of the University of Sydney, Australia, the scientists studied data obtained from lifestyle questionnaires completed by 55,487 people who were aged 50 to 64 years between 1993 and 1997.
Of the study participants, 64% were nonsmokers, 59% had an alcohol intake within recommended limits, 82% followed physical activity guidelines, and 76% had a waist circumference within normal limits, but only 2% followed all the guidelines.
Baseline index scores were zero or one for 8%, two for 26%, three for 40%, four for 25%, and five for only 1%. For every one point increase on the index, the incidence ratio was 0.88 for colon cancer and 0.89 for rectal cancer. Significantly, a score of four points was associated with a 30% risk reduction. If all participants followed one additional guideline, an estimated 13% of cases could have been prevented.A second trial of 530 persons found that lifestyle factors such as low literacy skills increase patient knowledge about bowel screening but not the rate of adherence with the procedure. Patients either received a consumer booklet containing information about bowel cancer screening or were assigned to a control group; those who received the decision aid had greater total knowledge (a mean score of 6.50/12 compared to 4.10/12); however, patients with the decision aid were 16% less likely to undergo the test, with 75% of controls taking the occult blood test compared with only 59% of the decision aid group.