title: Coffee and tea consumption in relation to inflammation and basal glucose metabolism in a multi-ethnic Asian population: a cross-sectional study.
abstract: BACKGROUND
  Higher coffee consumption has been associated with a lower risk of type 2 diabetes in cohort studies, but the physiological pathways through which coffee affects glucose metabolism are not fully understood. The aim of this study was to evaluate the associations between habitual coffee and tea consumption and glucose metabolism in a multi-ethnic Asian population and possible mediation by inflammation.
  
  
  METHODS
  We cross-sectionally examined the association between coffee, green tea, black tea and Oolong tea consumption and glycemic (fasting plasma glucose, HOMA-IR, HOMA-beta, plasma HbA1c) and inflammatory (plasma adiponectin and C-reactive protein) markers in a multi-ethnic Asian population (N = 4139).
  
  
  RESULTS
  After adjusting for multiple confounders, we observed inverse associations between coffee and HOMA-IR (percent difference: - 8.8% for ≥ 3 cups/day versus rarely or never; Ptrend = 0.007), but no significant associations between coffee and inflammatory markers. Tea consumption was not associated with glycemic markers, but green tea was inversely associated with plasma C-reactive protein concentrations (percent difference: - 12.2% for ≥ 1 cup/day versus < 1 cup/week; Ptrend = 0.042).
  
  
  CONCLUSIONS
  These data provide additional evidence for a beneficial effect of habitual caffeinated coffee consumption on insulin sensitivity, and suggest that this effect is unlikely to be mediated by anti-inflammatory mechanisms.
authors.affiliation: Life Sciences Institute, Centre for Life Sciences, National University of Singapore, 05-02, 28 Medical Drive, Singapore.
authors.forename: Salome A
authors.initials: SA
authors.lastname: Rebello
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: Chen
authors.forename: Nasheen
authors.initials: N
authors.lastname: Naidoo
authors.forename: Wang
authors.initials: W
authors.lastname: Xu
authors.forename: Jeannette
authors.initials: J
authors.lastname: Lee
authors.forename: Kee Seng
authors.initials: KS
authors.lastname: Chia
authors.forename: E Shyong
authors.initials: ES
authors.lastname: Tai
authors.forename: Rob M
authors.initials: RM
authors.lastname: van Dam
mesh_terms: D052242:Adiponectin / Q000097:blood; D000328:Adult; D044466:Asian People; D001481:Basal Metabolism / Q000187:drug effects*; D015415:Biomarkers; D015992:Body Mass Index; D002097:C-Reactive Protein / Q000032:analysis; D003069:Coffee; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005006:Ethnicity; D005069:Evaluation Studies as Topic; D005247:Feeding Behavior; D005260:Female; D005500:Follow-Up Studies; D005947:Glucose / Q000378:metabolism*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007249:Inflammation / Q000517:prevention & control; D007333:Insulin Resistance; D007407:Interviews as Topic; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D015999:Multivariate Analysis; D012307:Risk Factors; D012846:Singapore; D012907:Smoking; D011795:Surveys and Questionnaires; D013662:Tea
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D002097:C-Reactive Protein; D003069:Coffee; D005947:Glucose; D006442:Glycated Hemoglobin; D013662:Tea; C517652:hemoglobin A1c protein, human