Bianchi G D, Cerhan J R, Parker A S, Putnam S D, See W A, Lynch C F, Cantor K P
Department of Preventive Medicine and Environmental Health, The University of Iowa College of Medicine, Iowa City, USA.
Am J Epidemiol. 2000 Feb 15;151(4):377-83. doi: 10.1093/oxfordjournals.aje.a010217.
Recent epidemiologic studies have suggested that tea may be protective against cancers of the urinary tract. The authors examined the association between usual adult tea consumption and risk of bladder and kidney cancers in a population-based case-control study that included 1,452 bladder cancer cases, 406 kidney cancer cases, and 2,434 controls. For bladder cancer, the age- and sex-adjusted odds ratios (OR) (95% confidence intervals (CI)) referent to nonusers of tea were 0.9 (0.7, 1.1) for <1.0 cup/day, 1.0 (0.8, 1.2) for 1.0-2.6 cups/day, and 0.9 (0.7, 1.1) for >2.6 cups/day (cutpoints for users based on the tertile distribution among controls). When more extreme cutpoints were used, persons who consumed >5 cups/day (>90th percentile) had a suggestive decreased risk (OR = 0.7; 95% CI 0.5, 1.0), but there was no evidence of a dose-response relation. In analyses stratified by median total beverage intake (2.6 liters/day), there was an inverse association with tea use among persons who consumed less than the median (OR = 0.5; 95% CI 0.3, 0.8) but no association for persons who consumed at or above the median. In contrast, for kidney cancer, there was no association with tea use. Adjustment for site-specific risk factors did not alter these results. This study offers only minimal support for an inverse association between tea consumption and bladder or kidney cancer risk.
近期的流行病学研究表明，茶可能对泌尿系统癌症具有预防作用。作者在一项基于人群的病例对照研究中，调查了成年人日常饮茶与膀胱癌和肾癌风险之间的关联。该研究纳入了1452例膀胱癌病例、406例肾癌病例以及2434名对照。对于膀胱癌，以不饮茶者为参照，按年龄和性别调整后的比值比（OR）（95%置信区间[CI]），每日饮茶量<1.0杯者为0.9（0.7, 1.1），1.0 - 2.6杯者为1.0（0.8, 1.2），>2.6杯者为0.9（0.7, 1.1）（饮茶者的切点基于对照人群的三分位数分布）。当采用更极端的切点时，每日饮茶量>5杯（>第90百分位数）者的风险有降低的趋势（OR = 0.7；95% CI 0.5, 1.0），但未发现剂量反应关系。在按总饮料摄入量中位数（2.6升/天）分层的分析中，饮料摄入量低于中位数者饮茶与风险呈负相关（OR = 0.5；95% CI 0.3, 0.8），而摄入量等于或高于中位数者则无关联。相比之下，对于肾癌，饮茶与之无关联。对特定部位风险因素进行调整并未改变这些结果。这项研究仅为饮茶与膀胱癌或肾癌风险之间的负相关提供了极少的支持。
