Gao Y T, McLaughlin J K, Blot W J, Ji B T, Dai Q, Fraumeni J F
Shanghai Cancer Institute, People's Republic of China.
J Natl Cancer Inst. 1994 Jun 1;86(11):855-8. doi: 10.1093/jnci/86.11.855.
Studies in laboratory animals have suggested inhibitory effects of green tea on the induction of some cancers, notably, esophageal cancer. However, only a few epidemiologic studies have evaluated green tea as a potential inhibitor of human esophageal cancer.
Our purpose was to evaluate the relationship between green tea consumption and the risk of esophageal cancer.
This esophageal cancer study was part of a larger multicenter, case-control study that included three other gastrointestinal sites (pancreas, colon, and rectum). Medical records of patients aged 30-74 years old who were diagnosed with esophageal cancer from October 1, 1990, through January 31, 1993, were identified from the Shanghai Cancer Registry, which covers 6.8 million people in the urban area of Shanghai, People's Republic of China. During the ascertainment period, records of 1016 eligible cases of esophageal cancer were identified. Control subject records were selected by frequency matching in accordance with the age-sex distribution of the four gastrointestinal cancers ascertained by the cancer registry during 1986-1987. Patient interviews were then conducted using a structured, standardized questionnaire to obtain information on demographic characteristics, residential history, height and weight, diet, smoking, alcohol and tea drinking, medical history, family history of cancer, occupation, physical activity, and reproductive history.
Of the 902 patients interviewed, 734 (81.4%) had their disease pathologically confirmed. There were 1552 control subjects interviewed, including 240 alternates. All analyses of tea effects were conducted separately among men and women and all were adjusted for age. After further adjustment for other known confounders, a protective effect of green tea drinking on esophageal cancer was observed among women (odds ratio [OR] = 0.50; 95% confidence interval [CI] = 0.30-0.83), and this risk decreased (P for trend < or = .01) as tea consumption increased. Among men, the ORs were also below 1.00, although not statistically significant. ORs for green tea intake were estimated among those persons who neither smoked nor drank alcohol. In this subset, statistically significant decreases in risk among tea drinkers were observed for both men (OR = 0.43; 95% CI = 0.22-0.86; P for trend = .05) and women (OR = 0.40; 95% CI = 0.20-0.77; P for trend < .001).
This population-based, case-control study of esophageal cancer in urban Shanghai suggests a protective effect of green tea consumption. Although these findings are consistent with studies in laboratory animals, indicating that green tea can inhibit esophageal carcinogenesis, further investigations are definitely needed.
对实验动物的研究表明，绿茶对某些癌症的诱发具有抑制作用，尤其是食管癌。然而，仅有少数流行病学研究评估了绿茶作为人类食管癌潜在抑制剂的作用。
我们的目的是评估绿茶摄入量与食管癌风险之间的关系。
这项食管癌研究是一项更大规模的多中心病例对照研究的一部分，该研究还包括其他三个胃肠道部位（胰腺、结肠和直肠）。从上海癌症登记处识别出1990年10月1日至1993年1月31日期间被诊断为食管癌的30 - 74岁患者的病历，该登记处覆盖了中华人民共和国上海市市区680万人。在确定期间，识别出1016例符合条件的食管癌病例记录。对照对象记录是根据癌症登记处在1986 - 1987年确定的四种胃肠道癌症的年龄 - 性别分布，通过频率匹配选取的。然后使用结构化、标准化问卷对患者进行访谈，以获取有关人口统计学特征、居住史、身高和体重、饮食、吸烟、饮酒和饮茶、病史、癌症家族史、职业、身体活动和生殖史的信息。
在接受访谈的902名患者中，734名（81.4%）患者的疾病得到病理证实。共访谈了1552名对照对象，包括240名替代对象。所有关于茶的影响的分析均在男性和女性中分别进行，并且所有分析都根据年龄进行了调整。在进一步调整其他已知混杂因素后，观察到女性饮用绿茶对食管癌有保护作用（优势比[OR]=0.50；95%置信区间[CI]=0.30 - 0.83），并且随着茶摄入量的增加，这种风险降低（趋势P值≤0.01）。在男性中，OR值也低于1.00，尽管无统计学意义。在既不吸烟也不饮酒的人群中估计了绿茶摄入量的OR值。在这个亚组中，男性（OR = 0.43；95% CI = 0.22 - 0.86；趋势P值 = 0.05）和女性（OR = 0.40；95% CI = 0.20 - 0.77；趋势P值<0.001）饮茶者的风险均有统计学意义的降低。
这项基于上海市市区人群的食管癌病例对照研究表明，饮用绿茶具有保护作用。尽管这些发现与实验动物研究一致，表明绿茶可抑制食管癌发生，但仍肯定需要进一步研究。
