title: Associations of green tea and rock tea consumption with risk of impaired fasting glucose and impaired glucose tolerance in Chinese men and women.
abstract: OBJECTIVE
  To explore the associations of green tea and rock tea consumption with risk of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT).
  
  
  METHODS
  A multistage, stratified, cluster, random-sampling method was used to select a representative sample from Fujian Province in China. In total, 4808 subjects without cardiovascular disease, hypertension, cancer, or pancreatic, liver, kidney, or gastrointestinal diseases were enrolled in the study. A standard questionnaire was used to gather data on tea (green, rock, and black) consumption and other relevant factors. The assessment of impaired glucose regulation (IGR) was using 75-g oral glucose tolerance test (OGTT), the diagnostic criteria of normal glucose tolerance was according to American Diabetes Association.
  
  
  RESULTS
  Green tea consumption was associated with a lower risk of IFG, while rock tea consumption was associated with a lower risk of IGT. The adjusted odds ratios for IFG for green tea consumption of <1, 1-15, 16-30, and >30 cups per week were 1.0 (reference), 0.42 (95% confidence intervals (CI) 0.27-0.65), 0.23 (95% CI, 0.12-0.46), and 0.41 (95% CI, 0.17-0.93), respectively. The adjusted odds ratios for IGT for rock tea consumption of <1, 1-15, 16-30, and >30 cups per week were 1.0 (reference), 0.69 (95% CI, 0.48-0.98), 0.59 (95% CI, 0.39-0.90), and 0.64 (95% CI, 0.43-0.97), respectively. A U-shaped association was observed, subjects who consumed 16-30 cups of green or rock tea per week having the lowest odds ratios for IFG or IGT.
  
  
  CONCLUSIONS
  Consumption of green or rock tea may protect against the development of type 2 diabetes mellitus in Chinese men and women, particularly in those who drink 16-30 cups per week.
authors.affiliation: Department of Endocrinology, Fujian Provincial Hospital Key Laboratory of Endocrinology, Fujian Medical University, Fuzhou, Fujian, China.
authors.forename: Huibin
authors.initials: H
authors.lastname: Huang
authors.forename: Qiuxuan
authors.initials: Q
authors.lastname: Guo
authors.forename: Changsheng
authors.initials: C
authors.lastname: Qiu
authors.forename: Baoying
authors.initials: B
authors.lastname: Huang
authors.forename: Xianguo
authors.initials: X
authors.lastname: Fu
authors.forename: Jin
authors.initials: J
authors.lastname: Yao
authors.forename: Jixing
authors.initials: J
authors.lastname: Liang
authors.forename: Liantao
authors.initials: L
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Kaka
authors.initials: K
authors.lastname: Tang
authors.forename: Lixiang
authors.initials: L
authors.lastname: Lin
authors.forename: Jieli
authors.initials: J
authors.lastname: Lu
authors.forename: Yufang
authors.initials: Y
authors.lastname: Bi
authors.forename: Guang
authors.initials: G
authors.lastname: Ning
authors.forename: Junping
authors.initials: J
authors.lastname: Wen
authors.forename: Caijing
authors.initials: C
authors.lastname: Lin
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D002681:China / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000378:metabolism* / Q000517:prevention & control*; D005215:Fasting; D005260:Female; D005947:Glucose / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D011795:Surveys and Questionnaires; D013662:Tea
chemical_list: D013662:Tea; D005947:Glucose