title: The association of whole grain consumption with incident type 2 diabetes: the Women's Health Initiative Observational Study.
abstract: OBJECTIVE
  Whole grains may offer protection from diabetes by decreasing energy intake, preventing weight gain, and direct effects on insulin resistance. This study examined associations of whole and refined grains with incident type 2 diabetes (T2D) ascertained by self-reported medication use in a cohort of postmenopausal women.
  
  
  METHODS
  We included 72,215 women free of diabetes at baseline from the Women's Health Initiative Observational Study. Whole grain consumption was categorized as 0, less than 0.5, 0.5 to 1.0, 1.0 to less than 1.5, 1.5 to less than 2.0, and 2.0 or more servings per day. Proportional hazards regression was performed to estimate hazard ratios (HR) and 95% confidence intervals adjusting for potential confounders.
  
  
  RESULTS
  There were 3465 cases of incident T2D over median follow-up of 7.9 years. Adjusted for age and energy intake per day, successively increasing categories of whole grain consumption were associated with statistically significant reduced risk of incident T2D (HRs, 1.00, 0.83, 0.73, 0.69, 0.61, and 0.57; P for trend < 0.0001). Results were attenuated after adjustment for confounders and other dietary components. The reduction in risk of T2D was greater among nonsmokers and those who maintained their weight within 5 pounds with higher consumption of whole grains than smokers and women who gained more weight.
  
  
  CONCLUSIONS
  This large, prospective study found an inverse dose-response relationship between whole grain consumption and incident T2D in postmenopausal women.
authors.affiliation: HealthPartners Institute for Education and Research, 33rd Avenue S., Bloomington, MN 55440, USA. Emily.D.Parker@healthpartners.com
authors.forename: Emily D
authors.initials: ED
authors.lastname: Parker
authors.forename: Simin
authors.initials: S
authors.lastname: Liu
authors.forename: Linda
authors.initials: L
authors.lastname: Van Horn
authors.forename: Leslie F
authors.initials: LF
authors.lastname: Tinker
authors.forename: James M
authors.initials: JM
authors.lastname: Shikany
authors.forename: Charles B
authors.initials: CB
authors.lastname: Eaton
authors.forename: Karen L
authors.initials: KL
authors.lastname: Margolis
mesh_terms: D000368:Aged; D016001:Confidence Intervals; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control; D004032:Diet; D004034:Diet Surveys; D002523:Edible Grain; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D017698:Postmenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D016387:Women's Health