Tea consumption and its interactions with tobacco smoking and alcohol drinking on oral cancer in southeast China.
Epidemiological results on the association between tea consumption and oral cancer remain controversial. We aimed to evaluate the exact relationship between tea consumption and oral cancer in Chinese population.



A large-scale case-control study was conducted on 586 oral cancer patients and 1024 controls frequency-matched by age and gender. Epidemiological data were collected through face-to-face interviews with a structure questionnaire. Unconditional logistic regression model was used to assess the effect of tea consumption on oral cancer stratified by smoking, alcohol drinking and demographics. Quantity of tea consumed (ml/day) was categorized into five subgroups based on quartiles and then its interactions was evaluated with tobacco smoking and alcohol drinking at each subgroup.



Tea consumption showed an inverse association with oral cancer for non-smokers or non-alcohol drinkers (the odds ratios (ORs) were 0.610 (95% confidence interval (CI): 0.425-0.876) and 0.686 (95% CI: 0.503-0.934), respectively). For smokers or alcohol drinkers, decreased risk was only observed in those who consumed >800 ml/day. Furthermore, oolong tea consumption was associated with decreased risk of oral cancer in smokers or alcohol drinkers but not in non-smokers or non-alcohol drinkers. Tea consumption combined with smoking or/and alcohol drinking had a greater risk than tea consumption alone, but the risk was roughly reduced from zero to Q4 (>800 ml/day). Additionally, when stratified by demographics, the protective effect of tea was especially evident in females, urban residents, normal body mass index population (18.5-23.9), farmers, office workers and those aged <60 years.



Tea consumption protects against oral cancer in non-smokers or non-alcohol drinkers, but this effect may be obscured in smokers or alcohol drinkers. Additionally, demographics may modify the association between tea consumption and oral cancer.
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
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F
Chen
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
B-C
BC
He
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
L-J
LJ
Yan
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
F-P
FP
Liu
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
J-F
JF
Huang
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
Z-J
ZJ
Hu
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
Z
Z
Lin
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
X-Y
XY
Zheng
Department of Stomatology, the First Affiliated Hospital of Fujian Medical University, Fuzhou, China.
L-S
LS
Lin
Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, CA, USA.
Z-F
ZF
Zhang
Department of Epidemiology and Health Statistic, School of Public Health, Fujian Medical University, Fuzhou, China.
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L
Cai
D000328:Adult; D000368:Aged; D000428:Alcohol Drinking / Q000009:adverse effects*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000453:epidemiology / Q000209:etiology*; D016017:Odds Ratio; D012307:Risk Factors; D013662:Tea / Q000009:adverse effects*; D000073869:Tobacco Smoking / Q000009:adverse effects*
D013662:Tea