CAMBRIDGE, England, April 22 (UPI) — How study participants complete food diaries and food frequency questionnaires may impact cancer study results, British researchers suggest.
Researchers at the University of Cambridge in England led by Christina Dahm and Kay-Tee Khaw used data from seven diet studies that included 579 patients who developed colorectal cancer at least one year after they began recording what they ate.
The researchers examined fiber intake of those using food diaries and the questionnaires who got colorectal cancer versus the fiber intake of 1,996 control subjects who did not develop colorectal cancer — matched for sex, age, and date of diary completion.
The study, published in the Journal of the National Cancer Institute, found for those using food diaries the odds of developing colorectal cancer was 30 percent lower for those eating an average of 24 grams per day of dietary fiber versus those who ate an average 10 grams of fiber per day. However, the food frequency questionnaires indicated no statistically significant association between fiber intake and the risk of colorectal cancer.
“The fact that we found no association using the food frequency questionnaire may explain the lack of convincing evidence relating fiber intake to a substantial reduction in colorectal cancer risk in some previous studies that relied on food frequency questionnaires,” the authors said in a statement.
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