PURPOSE
To analyze associations between colorectal cancer progression and diet scores calculated using published scoring approaches for three dietary patterns: Healthy Eating Index (HEI), Mediterranean Diet (Mediterranean), and Dietary Approaches to Stop Hypertension Diet (DASH).
BACKGROUND
Little is known about whether longterm risk for progression to colorectal cancer is associated with recommended healthy dietary patterns among US veterans. Previous studies of veterans have shown higher intake of fiber and vitamin D reduced risk, and red meat increased risk for finding colorectal cancer precursors during colonoscopy. However, studying dietary patterns in aggregate may be more clinically relevant for longitudinal studies of colorectal cancer prevention.
METHODS
3,121 asymptomatic US veterans aged 50-75 received colonoscopy between 1994-97 and were followed through 2009. Most significant colonoscopy findings (MSCF) across the study period were: (i) no neoplasia (NN), (ii) non-advanced adenomas (NAAs) or (iii) advanced neoplasia (AN). Baseline dietary questionnaire data were used to calculate three dietary pattern (HEI, Mediterranean, and DASH) scores.
DATA ANALYSIS
Multinomial logistic regression models were used in a cross-sectional analysis to test for associations represented by adjusted odds ratios (aOR) between MSCF and dietary pattern scores, controlling for demographics and clinical risk factors.
RESULTS
Among 3,023 participants with complete data, 97% were male, and 83.8% were White. Increasing scores, representing healthier diets, for each dietary pattern had similar or lower odds for NAAs and AN, respectively, versus NN. They were HEI: aOR: 1.00, 95% CI: 0.99-1.01 and aOR 0.97, 95% CI: 0.99-1.01; Mediterranean: aOR: 0.98, 95% CI: 0.95-1.02 and aOR 0.95, 95% CI: 0.90-0.999; DASH: aOR: 0.99, 95% CI: 0.99- 1.00 and aOR 0.99, 95% CI: 0.98-0.999. Across each dietary pattern, higher whole grain and fiber category scores generally had lower odds for NAAs and AN.
CONCLUSIONS
Study results revealed that overall higher dietary quality and specific dietary components of whole grain or fiber intake, based on three different dietary patterns suggest lower odds for CRC precursors. Findings indicate potential differences in dietary intake patterns and more research is needed to determine the benefit of developing tailored CRC screening and surveillance clinical guidelines.