title: Coffee consumption and incidence of impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes: the Hoorn Study.
abstract: OBJECTIVE
  Coffee contains several substances that may affect glucose metabolism. The aim of this study was to evaluate the relationship between habitual coffee consumption and the incidence of IFG, IGT and type 2 diabetes.
  
  
  METHODS
  We used cross-sectional and prospective data from the population-based Hoorn Study, which included Dutch men and women aged 50-74 years. An OGTT was performed at baseline and after a mean follow-up period of 6.4 years. Associations were adjusted for potential confounders including BMI, cigarette smoking, physical activity, alcohol consumption and dietary factors.
  
  
  RESULTS
  At baseline, a 5 cup per day higher coffee consumption was significantly associated with lower fasting insulin concentrations (-5.6%, 95% CI -9.3 to -1.6%) and 2-h glucose concentrations (-8.8%, 95% CI -11.8 to -5.6%), but was not associated with lower fasting glucose concentrations (-0.8%, 95% CI -2.1 to 0.6%). In the prospective analyses, the odds ratio (OR) for IGT was 0.59 (95% CI 0.36-0.97) for 3-4 cups per day, 0.46 (95% CI 0.26-0.81) for 5-6 cups per day, and 0.37 (95% CI 0.16-0.84) for 7 or more cups per day, as compared with the corresponding values for the consumption of 2 or fewer cups of coffee per day (p=0.001 for trend). Higher coffee consumption also tended to be associated with a lower incidence of type 2 diabetes (OR 0.69, CI 0.31-1.51 for >/=7 vs </=2 cups per day, p=0.09 for trend), but was not associated with the incidence of IFG (OR 1.35, CI 0.80-2.27 for >/=7 vs </=2 cups per day, p=0.49 for trend).
  
  
  CONCLUSIONS
  Our findings indicate that habitual coffee consumption can reduce the risk of IGT, and affects post-load rather than fasting glucose metabolism.
authors.affiliation: Department of Nutrition and Health, Faculty of Earth and Life Sciences, Vrije University Amsterdam, de Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands. rob.van.dam@falw.vu.nl
authors.forename: R M
authors.initials: RM
authors.lastname: van Dam
authors.forename: J M
authors.initials: JM
authors.lastname: Dekker
authors.forename: G
authors.initials: G
authors.lastname: Nijpels
authors.forename: C D A
authors.initials: CD
authors.lastname: Stehouwer
authors.forename: L M
authors.initials: LM
authors.lastname: Bouter
authors.forename: R J
authors.initials: RJ
authors.lastname: Heine
mesh_terms: D001786:Blood Glucose / Q000378:metabolism*; D003069:Coffee; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology*; D005260:Female; D018149:Glucose Intolerance / Q000097:blood / Q000453:epidemiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D012727:Sex Characteristics
chemical_list: D001786:Blood Glucose; D003069:Coffee; D007328:Insulin