Associations Between Prescreening Dietary Patterns and Longitudinal Colonoscopy Outcomes in Veterans

Understanding associations between diet and long-term risk for colorectal cancer (CRC) among US veterans may provide insight for patient-clinician decisions about lifestyle recommendations as part of a CRC screening program.

Asymptomatic US veterans aged 50 to 75 years who received screening colonoscopy between 1994 and 1997 were followed through 2009. The most significant colonoscopy findings (MSCFs) across the study period were classified as no neoplasia, not advanced adenomas, or advanced neoplasia (AN). The food frequency questionnaire was used to calculate raw and percent scores for the Healthy Eating Index (HEI), Mediterranean diet (MD), and Dietary Approaches to Stop Hypertension (DASH) dietary patterns. In cross-sectional analyses, multinomial logistic regression models tested for associations between dietary pattern scores and MSCF, controlling for demographics.

Among 3023 participants with complete data, 96.7% were male, and 83.8% were non-Hispanic White. Higher dietary patterns scores (ie, healthier diet) had similar or lower adjusted odds ratios (aORs) for AN vs no neoplasia (HEI: aOR, 1.00 [95% CI, 0.99-1.01]; MD: aOR, 0.95 [95% CI, 0.90-1.00]; DASH: aOR, 0.99 [95% CI, 0.98-1.00]). Higher grain category scores generally had lower aORs for AN for each dietary pattern (HEI: aOR, 0.96 [95% CI, 0.93-0.99]; MD: aOR, 0.29 [95% CI, 0.14-0.62]; DASH: aOR, 0.86 [95% CI, 0.78-0.95]).

Healthy dietary patterns were associated with lower aORs for colonic neoplasia among veterans enrolled in a CRC screening program. More research is needed to determine the role of dietary assessments for tailored CRC prevention and surveillance.