title: Tea drinking and cognitive function in oldest-old Chinese.
abstract: OBJECTIVE
  We examined the longitudinal association between tea drinking frequency and cognitive function in a large sample of oldest-old Chinese.
  
  
  METHODS
  population-based longitudinal cohort study.
  
  
  METHODS
  The Chinese Longitudinal Healthy Longevity Survey (CLHLS).
  
  
  METHODS
  7139 participants aged 80 to 115 (mean age 91.4 years) who provided complete data at baseline (year 1998).
  
  
  METHODS
  Current frequency of tea drinking and past frequency at age 60 were ascertained at baseline, and baseline and follow-up cognitive assessments were performed in the years 1998 (n=7139), 2000 (n=4081), 2002 (n=2288) and 2005 (n=913) respectively. Verbal fluency test was used as measure of cognitive function.
  
  
  RESULTS
  Tea drinking was associated at baseline with higher mean (SD) verbal fluency scores: daily=10.7 (6.6), occasional=9.2 (5.8), non-drinker=9.0 (5.5). In linear mixed effects model that adjusted for age, gender, years of schooling, physical exercise and activities score, the regression coefficient for daily drinking (at age 60) and occasional drinking was 0.72 (P<0.0001) and 0.41(P=0.01) respectively. Tea drinkers had higher verbal fluency scores throughout the follow-up period but concurrently had a steeper slope of cognitive decline as compared with non-drinkers (coefficient for the interaction term Time*Daily drinking= -0.12, P=0.02; "Time" was defined as the time interval from baseline to follow-up assessments in years). Similar results were found for current tea drinking status at study baseline year (1998) as predictor variable.
  
  
  CONCLUSIONS
  Regular tea drinking is associated with better cognitive function in oldest-old Chinese.
authors.affiliation: Department of Psychological Medicine, National University of Singapore. pcmfl@nus.edu.sg
authors.forename: L
authors.initials: L
authors.lastname: Feng
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: T-P
authors.initials: TP
authors.lastname: Ng
authors.forename: T-S
authors.initials: TS
authors.lastname: Lee
authors.forename: E-H
authors.initials: EH
authors.lastname: Kua
authors.forename: Y
authors.initials: Y
authors.lastname: Zeng
mesh_terms: D000369:Aged, 80 and over; D044466:Asian People; D028241:Camellia sinensis; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000517:prevention & control*; D004327:Drinking Behavior; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D007806:Language Disorders / Q000517:prevention & control; D008137:Longitudinal Studies; D008297:Male; D008517:Phytotherapy; D028321:Plant Preparations / Q000494:pharmacology / Q000627:therapeutic use*; D013662:Tea
chemical_list: D028321:Plant Preparations; D013662:Tea