Abstract 627: Associations of novel dietary and lifestyle inflammation scores with incident colorectal cancer in the National Institutes of Health-American Association of Retired Persons Diet and Health study
Authors: Byrd Doratha , Bostick Roberd M. , Judd Suzanne E. , Flanders William D. , Hartman Terryl J. , Fedirko Veronika , Reedy Jill , Agurs-Collins Tanya 
Published: August 2019

Chronically higher inflammation may play a role in colorectal carcinogenesis. Contributors to inflammation likely include dietary and other lifestyle exposures, such as smoking, physical activity, alcohol intake, and obesity. We developed dietary (DIS) and lifestyle (LIS) inflammation scores to characterize the aggregate contributions of dietary and lifestyle exposures to systemic inflammation, and investigated associations of the scores with incident colorectal cancer (CRC) in the prospective National Institutes of Health-American Association of Retired Persons (NIH-AARP) Diet and Health Study cohort (n = 453,465).

To develop the 19-component DIS, we selected a priori 18 whole food groups, including leafy greens, deep-orange/yellow vegetables, apples/berries, tomatoes/tomato products, other fruits and vegetables, processed meats, red meats, poultry, fish, nuts, legumes, refined grains or starchy vegetables, added sugars, saturated/trans fats, coffee and tea, high- and low-fat dairy, plus a supplemental micronutrient score. Similarly, for the 4-component LIS we selected a priori smoking status, physical activity, alcohol intake, and body mass index. The components were weighted based on the strengths of their associations with a panel of circulating inflammation biomarker concentrations (high sensitivity C-reactive protein and interleukin [IL]-6, IL-8, and IL-10) in a subset of 639 male and female, black and white participants in the Reasons for Geographic and Racial Differences in Stroke cohort study (REGARDS). The sums of the weighted components constitute the scores, such that higher scores reflect a higher balance of more pro-inflammatory exposures. Applying the component weights developed in REGARDS, we calculated a DIS and LIS using baseline data from the NIH-AARP study cohort and investigated their associations with incident CRC using multivariable Cox proportional hazards regression, adjusted for established risk factors for CRC.

Over an average of 13.5 years of follow-up, 10,336 participants were diagnosed with CRC. With increasing levels of the DIS and LIS, there was increasing risk for incident CRC. For men and women in the highest relative to the lowest quintiles of the DIS and LIS, the multivariable-adjusted hazards ratios (HR) and their 95% confidence intervals [CIs]) were: 1.3 (95% CI: 1.2, 1.4; Ptrend: &lt;0.001) and 1.4 (95% CI: 1.3, 1.5; Ptrend: &lt;0.001), respectively. The HR for those in the highest relative to the lowest joint DIS/LIS quintile was 1.8 (95% CI: 1.7, 2.0; Pinteraction: &lt;0.001). The DIS and LIS associations were strongest among men and for cancers of the colon among men and women combined.

These results suggest that pro-inflammatory diet and lifestyle exposures may be associated with higher risk for incident colorectal cancer.

Citation Format: Doratha Byrd, Roberd M. Bostick, Suzanne E. Judd, William D. Flanders, Terryl J. Hartman, Veronika Fedirko, Jill Reedy, Tanya Agurs-Collins. Associations of novel dietary and lifestyle inflammation scores with incident colorectal cancer in the National Institutes of Health-American Association of Retired Persons Diet and Health study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 627.