Prospective cohort study of tea consumption and risk of digestive system cancers: results from the Shanghai Women's Health Study.
BACKGROUND
Data from in vitro and animal studies support a protective role for tea in the etiology of digestive system cancers; however, results from prospective cohort studies have been inconsistent. In addition, to our knowledge, no study has investigated the association of tea consumption with the incidence of all digestive system cancers in Chinese women.


OBJECTIVE
We investigated the association of regular tea intake (≥3 times/wk for >6 mo) with risk of digestive system cancers.


METHODS
We used the Shanghai Women's Health Study, a population-based prospective cohort study of middle-aged and older Chinese women who were recruited in 1996-2000. Adjusted HRs and associated 95% CIs were derived from Cox regression models.


RESULTS
After a mean follow-up of 11 y, 1255 digestive system cancers occurred (stomach, esophagus, colorectal, liver, pancreas, and gallbladder/bile duct cancers) in 69,310 nonsmoking and non-alcohol-drinking women. In comparison with women who never drank tea, regular tea intake (mostly green tea) was associated with reduced risk of all digestive system cancers combined (HR: 0.86; 95% CI: 0.74, 0.98), and the reduction in risk increased as the amount and years of tea consumption increased (P-trend = 0.01 and P-trend < 0.01, respectively). For example, women who consumed ≥150 g tea/mo (∼2-3 cups/d) had a 21% reduced risk of digestive system cancers combined (HR: 0.79; 95% CI: 0.63, 0.99). The inverse association was found primarily for colorectal and stomach/esophageal cancers.


CONCLUSIONS
In this large prospective cohort study, tea consumption was associated with reduced risk of colorectal and stomach/esophageal cancers in Chinese women.
Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37203-1738, USA.
Sarah
S
Nechuta
Xiao-Ou
XO
Shu
Hong-Lan
HL
Li
Gong
G
Yang
Bu-Tian
BT
Ji
Yong-Bing
YB
Xiang
Hui
H
Cai
Wong-Ho
WH
Chow
Yu-Tang
YT
Gao
Wei
W
Zheng
D000328:Adult; D000368:Aged; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D004067:Digestive System Neoplasms / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012959:Socioeconomic Factors; D013662:Tea; D014505:Urban Population
D013662:Tea