title: Comparison of 4 established DASH diet indexes: examining associations of index scores and colorectal cancer.
abstract: BACKGROUND
  Multiple diet indexes have been developed to capture the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and examine relations with health outcomes but have not been compared within the same study population to our knowledge.
  
  
  OBJECTIVE
  We compared 4 established DASH indexes and examined associations with colorectal cancer.
  
  
  METHODS
  Scores were generated from a food-frequency questionnaire in the NIH-AARP Diet and Health Study (n = 491,841). Separate indexes defined by Dixon (7 food groups, saturated fat, and alcohol), Mellen (9 nutrients), Fung (7 food groups and sodium), and Günther (8 food groups) were used. HRs and 95% CIs for colorectal cancer were generated by using Cox proportional hazard models.
  
  
  RESULTS
  From 1995 through 2006, 6752 incident colorectal cancer cases were ascertained. In men, higher scores were associated with reduced colorectal cancer incidence by comparing highest to lowest quintiles for all indexes as follows: Dixon (HR: 0.77; 95% CI: 0.69, 0.87), Mellen (HR: 0.78; 95% CI: 0.71, 0.86), Fung (HR: 0.75; 95% CI: 0.68, 0.83), and Günther (HR: 0.81; 95% CI: 0.74, 0.90). Higher scores in women were inversely associated with colorectal cancer incidence by using methods defined by Mellen (HR: 0.79; 95% CI: 0.68, 0.91), Fung (HR: 0.84; 95% CI: 0.73, 0.96), and Günther (HR: 0.84; 95% CI: 0.73.0.97) but not Dixon (HR: 1.01; 95% CI: 0.80, 1.28).
  
  
  CONCLUSIONS
  The consistency in findings, particularly in men, suggests that all indexes capture an underlying construct inherent in the DASH dietary pattern, although the specific index used can affect results.
authors.affiliation: Cancer Prevention Fellowship Program, National Cancer Institute, Rockville, MD, USA. pmiller@exponent.com
authors.forename: Paige E
authors.initials: PE
authors.lastname: Miller
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Cross
authors.forename: Amy F
authors.initials: AF
authors.lastname: Subar
authors.forename: Susan M
authors.initials: SM
authors.lastname: Krebs-Smith
authors.forename: Yikyung
authors.initials: Y
authors.lastname: Park
authors.forename: Tiffany
authors.initials: T
authors.lastname: Powell-Wiley
authors.forename: Albert
authors.initials: A
authors.lastname: Hollenbeck
authors.forename: Jill
authors.initials: J
authors.lastname: Reedy
mesh_terms: D015179:Colorectal Neoplasms / Q000517:prevention & control*; D016001:Confidence Intervals; D004032:Diet; D004034:Diet Surveys; D005260:Female; D006801:Humans; D006973:Hypertension / Q000178:diet therapy; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012737:Sex Factors; D011795:Surveys and Questionnaires