Black tea consumption and risk of rectal cancer in Moscow population.
OBJECTIVE
This population-based case-control study (663 cases and 323 controls) examined the effect of black tea intake on the risk of rectal cancer in Moscow residents. The Moscow population was selected for its wide range of black tea consumption.


METHODS
This study used three measures of tea consumption: the volume of beverage (l/month), zavarka (tea concentrate, l/month), and dry tea (g/month). We calculated the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for these three parameters of tea intake using logistic regression.


RESULTS
Greater use of dry tea was associated with lower risk of rectal cancer in women (high vs. low: OR = 0.40; 95% CI, 0.23-0.70) and in men (high vs. low: OR = 0.77; 95% CI, 0.42-1.43). The observed effect was weaker when tea was measured as zavarka (high vs. low in women: OR = 0.47; 95% CI, 0.26-0.83; in men: OR = 0.99; 95% CI, 0.52-1.96) and as beverage volume (high vs. low in women: OR = 0.68; 95% CI, 0.39-1.19; in men: OR = 1.03; 95% CI, 0.53-2.09).


CONCLUSIONS
These findings support the hypothesis that black tea consumption reduces the risk of rectal cancer. The attenuation of the effect across the three measures of tea intake can be explained by an increasing degree of exposure misclassification from dry tea to zavarka and beverage volume.
Dora
Il'yasova
I
Department of Epidemiology, University of North Carolina at, Chapel Hill, NC 27157, USA. dilyasov@wfubmc.edu
Arab
Lenore
L
Martinchik
Arseny
A
Sdvizhkov
Alexander
A
Urbanovich
Leonard
L
Weisgerber
Ute
U
D000230:Adenocarcinoma / Q000453:epidemiology / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects; D028241:Camellia sinensis; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D015986:Confounding Factors, Epidemiologic; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior; D005260:Female; D006306:Health Surveys; D006801:Humans; D007407:Interviews as Topic; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009031:Moscow / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D013662:Tea
D013662:Tea