title: Index-based dietary patterns and colorectal cancer risk: a systematic review.
abstract: Colorectal cancer (CRC) is the third most common cancer in both men and women in the United States. Various a priori dietary patterns that take into account diet complexity have been associated with CRC risk. This systematic review augments the evidence for an association between CRC risk and the Mediterranean Diet Score (MDS) and the Healthy Eating Index (HEI), and provides new evidence for a novel Dietary Inflammatory Index (DII). Human studies published in English after 31 December 2008 were reviewed. Five case-control studies and 7 prospective cohort studies conducted in the United States and Europe were identified. Five of the studies examined the MDS, 4 examined the HEI, and 4 examined the DII. Comparing highest to lowest score groups, higher MDSs were associated with an 8-54% lower CRC risk, and higher HEI scores were associated with a 20-56% lower CRC risk. More proinflammatory diet scores were associated with a 12-65% higher CRC risk compared with more anti-inflammatory diets in studies that used the DII. The results reported by sex suggested similar associations for men and women. This review builds upon the evidence supporting the association between higher overall diet quality and lower risk of CRC. Increasing scores of MDS and HEI and anti-inflammatory DII scores are characterized by high intake of plant-based foods and low intake of animal products. Future studies in more diverse populations and with consistent scoring calculations are recommended.
authors.affiliation: Department of Epidemiology and Biostatistics and Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC; and ssteck@sc.edu.
authors.forename: Susan E
authors.identifier: http://orcid.org/0000-0002-3201-9537
authors.initials: SE
authors.lastname: Steck
authors.affiliation: Department of Epidemiology and Biostatistics and Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC; and.
authors.forename: Mark
authors.initials: M
authors.lastname: Guinter
authors.affiliation: Department of Epidemiology and Biostatistics and Cancer Prevention and Control Program, Arnold School of Public Health, University of South Carolina, Columbia, SC; and.
authors.forename: Jiali
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Mel and Enid Zuckerman College of Public Health and Arizona Cancer Center, University of Arizona, Tucson, AZ.
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Thomson
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology; D004032:Diet; D038441:Diet, Mediterranean; D005060:Europe; D005247:Feeding Behavior; D005260:Female; D006293:Health Promotion; D006801:Humans; D007249:Inflammation; D008019:Life Style; D016239:MEDLINE; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States
keywords: Dietary Inflammatory Index; Healthy Eating Index; Mediterranean diet; colorectal cancer; dietary patterns; epidemiology; systematic review