Black and green tea consumption and the risk of coronary artery disease: a meta-analysis.
BACKGROUND
Epidemiologic studies are inconsistent regarding the association between tea consumption and the risk of coronary artery disease (CAD).


OBJECTIVE
The objective was to perform a meta-analysis to determine whether an association exists between tea consumption and total CAD endpoints in observational studies.


METHODS
We searched PUBMED and EMBASE databases for studies conducted from 1966 through November 2009. Study-specific risk estimates were combined by using a random-effects model.


RESULTS
A total of 18 studies were included in the meta-analysis: 13 studies on black tea and 5 studies on green tea. For black tea, no significant association was found through the meta-analysis [highest compared with lowest, summary relative risk (RR): 0.92; 95% CI: 0.82, 1.04; an increment of 1 cup/d, summary RR: 0.98; 95% CI: 0.94, 1.02]. For green tea, the summary RR indicated a significant association between the highest green tea consumption and reduced risk of CAD (summary RR: 0.72; 95% CI: 0.58, 0.89). Furthermore, an increase in green tea consumption of 1 cup/d was associated with a 10% decrease in the risk of developing CAD (summary RR: 0.90; 95% CI: 0.82, 0.99).


CONCLUSIONS
Our data do not support a protective role of black tea against CAD. The limited data available on green tea support a tentative association of green tea consumption with a reduced risk of CAD. However, additional studies are needed to make a convincing case for this association.
Department of Cardiology, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Ze-Mu
ZM
Wang
Bo
B
Zhou
Yong-Sheng
YS
Wang
Qing-Yue
QY
Gong
Qi-Ming
QM
Wang
Jian-Jun
JJ
Yan
Wei
W
Gao
Lian-Sheng
LS
Wang
D003324:Coronary Artery Disease / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D012307:Risk Factors; D013662:Tea
D013662:Tea