Green tea consumption and cognitive function: a cross-sectional study from the Tsurugaya Project 1.
BACKGROUND
Although considerable experimental and animal evidence shows that green tea may possess potent activities of neuroprotection, neurorescue, and amyloid precursor protein processing that may lead to cognitive enhancement, no human data are available.


OBJECTIVE
The objective was to examine the association between green tea consumption and cognitive function in humans.


METHODS
We analyzed cross-sectional data from a community-based Comprehensive Geriatric Assessment (CGA) conducted in 2002. The subjects were 1003 Japanese subjects aged > or =70 y. They completed a self-administered questionnaire that included questions about the frequency of green tea consumption. We evaluated cognitive function by using the Mini-Mental State Examination with cutoffs of <28, <26, and <24 and calculated multivariate-adjusted odds ratios (ORs) of cognitive impairment.


RESULTS
Higher consumption of green tea was associated with a lower prevalence of cognitive impairment. At the <26 cutoff, after adjustment for potential confounders, the ORs for the cognitive impairment associated with different frequencies of green tea consumption were 1.00 (reference) for < or =3 cups/wk, 0.62 (95% CI: 0.33, 1.19) for 4-6 cups/wk or 1 cup/d, and 0.46 (95% CI: 0.30, 0.72) for > or =2 cups/d (P for trend = 0.0006). Corresponding ORs were 1.00 (reference), 0.60 (95% CI: 0.35, 1.02), and 0.87 (95% CI: 0.55, 1.38) (P for trend = 0.33) for black or oolong tea and 1.00 (reference), 1.16 (95% CI: 0.78, 1.73), and 1.03 (95% CI: 0.59, 1.80) (P for trend = 0.70) for coffee. The results were essentially the same at cutoffs of <28 and <24.


CONCLUSIONS
A higher consumption of green tea is associated with a lower prevalence of cognitive impairment in humans.
Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan. kuriyama-thk@umin.ac.jp
Shinichi
S
Kuriyama
Atsushi
A
Hozawa
Kaori
K
Ohmori
Taichi
T
Shimazu
Toshifumi
T
Matsui
Satoru
S
Ebihara
Shuichi
S
Awata
Ryoichi
R
Nagatomi
Hiroyuki
H
Arai
Ichiro
I
Tsuji
D000368:Aged; D000375:Aging / Q000523:psychology*; D001628:Beverages; D028241:Camellia sinensis / Q000737:chemistry; D003069:Coffee; D003072:Cognition Disorders / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D011594:Psychometrics; D011795:Surveys and Questionnaires; D013662:Tea
D003069:Coffee; D013662:Tea