title: Coffee Consumption, Newly Diagnosed Diabetes, and Other Alterations in Glucose Homeostasis: A Cross-Sectional Analysis of the Longitudinal Study of Adult Health (ELSA-Brasil).
abstract: BACKGROUND
  Observational studies have reported fairly consistent inverse associations between coffee consumption and risk of type 2 diabetes, but this association has been little investigated with regard to lesser degrees of hyperglycemia and other alterations in glucose homeostasis. Additionally, the association between coffee consumption and diabetes has been rarely investigated in South American populations. We examined the cross-sectional relationships of coffee intake with newly diagnosed diabetes and measures of glucose homeostasis, insulin sensitivity, and insulin secretion, in a large Brazilian cohort of middle-aged and elderly individuals.
  
  
  METHODS
  We used baseline data from 12,586 participants of the Longitudinal Study of Adult Health (ELSA-Brasil). Logistic regression analyses were performed to examine associations between coffee consumption and newly diagnosed diabetes. Analysis of covariance was used to assess coffee intake in relation to two-hour glucose from an oral glucose tolerance test, fasting glucose, glycated hemoglobin, fasting and -2-hour postload insulin and measures of insulin sensitivity.
  
  
  RESULTS
  We found an inverse association between coffee consumption and newly diagnosed diabetes, after adjusting for multiple covariates [23% and 26% lower odds of diabetes for those consuming coffee 2-3 and >3 times per day, respectively, compared to those reporting never or almost never consuming coffee, (p = .02)]. An inverse association was also found for 2-hour postload glucose [Never/almost never: 7.57 mmol/L, ≤1 time/day: 7.48 mmol/L, 2-3 times/day: 7.22 mmol/L, >3 times/day: 7.12 mol/L, p<0.0001] but not with fasting glucose concentrations (p = 0.07). Coffee was additionally associated with 2-hour postload insulin [Never/almost never: 287.2 pmol/L, ≤1 time/day: 280.1 pmol/L, 2-3 times/day: 275.3 pmol/L, >3 times/day: 262.2 pmol/L, p = 0.0005) but not with fasting insulin concentrations (p = .58).
  
  
  CONCLUSIONS
  Our present study provides further evidence of a protective effect of coffee on risk of adult-onset diabetes. This effect appears to act primarily, if not exclusively, through postprandial, as opposed to fasting, glucose homeostasis.
authors.affiliation: Postgraduate Studies Program in Epidemiology, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: James
authors.initials: J
authors.lastname: Yarmolinsky
authors.affiliation: Postgraduate Studies Program in Epidemiology, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil; Department of Epidemiology, Mailman School of Public Health, Columbia University Medical Center, New York, NY, United States of America; Institute of Human Nutrition and Department of Medicine, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, United States of America.
authors.forename: Noel T
authors.initials: NT
authors.lastname: Mueller
authors.affiliation: Postgraduate Studies Program in Epidemiology, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Duncan
authors.affiliation: Center for Health Sciences, Federal University of Espirito Santo, Vitória, Espírito Santo, Brazil.
authors.forename: Maria Del Carmen
authors.initials: Mdel C
authors.lastname: Bisi Molina
authors.affiliation: Center for Clinical and Epidemiological Research, Hospital Universitário, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Alessandra C
authors.initials: AC
authors.lastname: Goulart
authors.affiliation: Postgraduate Studies Program in Epidemiology, School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
authors.forename: Maria Inês
authors.initials: MI
authors.lastname: Schmidt
mesh_terms: D001938:Brazil / Q000453:epidemiology; D003069:Coffee; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D006943:Hyperglycemia / Q000453:epidemiology; D007328:Insulin / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged
chemical_list: D003069:Coffee; D005947:Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human