饮绿茶与成年人白血病发病风险的病例对照研究

目的 探讨饮用绿茶与成年人白血病发病风险的关系.方法 采用配对病例对照研究,收集2005年1月至2006年12月确诊的白血病患者107例,以同期骨科非肿瘤住院患者110例对照,采用面对面交谈的方式,使用统一的调查问卷,收集所有对象的饮茶量、饮茶持续年限和频率、暴露于放射线及职业危害因素、药物应用等信息;用SPSS软件进行单因素、多因素非条件logistic回归分析评估OR值及其95%CI,.结果 与不饮茶组相比,随着饮用绿茶的量、持续年限和频率增加,成年人患白血病的危险度呈下降趋势.单因素分析显示,饮绿茶组患白血病的OR=0.58(95%CI:0.34～1.00;P＜0.05),在对性别、年龄、居住地、吸烟、受教育程度、暴露于射线及职业危害因素等混杂因素进行调整后,饮绿茶组发生白血病的OR=0.52(95%CI:0.28～0.98;P=0.04),且随着饮茶频率、饮茶年限和饮用茶叶量的增加,OR值逐渐降低,结果有统计学意义.结论 饮绿茶可能是成年人白血病的保护性因素,并与饮绿茶频率、饮绿茶量及饮绿茶时间有关.     

Cruciferous vegetables, genetic polymorphisms in glutathione S-transferases M1 and T1, and prostate cancer risk

Cruciferous vegetables contain anticarcinogenic isothiocyanates (ITCs), particularly the potent sulforaphane, which may decrease risk of prostate cancer through induction of phase II enzymes, including glutathione S-transferases (GSTs). We evaluated this hypothesis in a population-based, case-control study of prostate cancer, including 428 men with incident prostate cancer and 537 community controls. An in-person interview included an extensive food-frequency questionnaire. Genotyping for deletions in GSTM1 and GSTT1 was performed in a subset of men who provided blood. Intakes of cruciferous vegetables and of broccoli, the greatest source of sulforaphane, were associated with decreased prostate cancer risk at all levels above the lowest consumers [adjusted 4th quartile odds ratio (OR)=0.58; 95% confidence interval (CI)=0.38, 0.89, and 0.72 (95% CI=0.49, 1.06)], respectively. In relation to genotypes, there was a nonsignificant increase in risk with the GSTT1 null genotype (OR=1.51; 95% CI=0.98, 2.31) but no effects of GSTM1 genotype. However, men with GSTM1-present genotype and high broccoli intake had the greatest reduction in risk (OR=0.49; 95% CI=0.27, 0.89). Our findings provide evidence that two or more servings per month of cruciferous vegetables may reduce risk of prostate cancer, especially among men with GSTM1-present alleles, and are consistent with a role of dietary ITCs as chemopreventive agents against prostate cancer.     

中国汉族人口三种谷胱甘肽S-转移酶基因多态性分析

目的：分析中国汉族人口谷胱甘肽S－转移酶（GSTs)基因多态性分布。方法：样本为450名中国汉族人口,采用多重等位基因特异聚合酶链反应（PCR）方法分析GSTM1和GSTT1基因多态性,采用PCR－限制性片段长度多态性方法分析GSTP1＋313核苷酸位点的基因多态性。结果：GSTM1缺失型和GSTT1缺失型基因型频率分别为57％和45％,同时具有GSTM1缺失型和GSTT1缺失型基因型的人个体频率为28．92％;而GSTP1＋313位点G等位基因频率为18．7％,并发现该人群中同时具有3种危险基因型（GSTM1缺失型、GSTT1缺失型和GSTP1＋313A／A）的个体频率为18．04％。GSTs基因型分布不受性别和年龄的影响。结论：中国汉族人口GSTM1、GSTT1和GSTP1基因呈多态性分布,其等位基因和基因型频率不同于其他种族。     

Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies

Observational studies on tea consumption and prostate cancer (PCa) risk are still inconsistent. The authors conducted a meta-analysis to investigate the association between green tea and black tea consumption with PCa risk. Thirteen studies providing data on green tea or black tea consumption were identified by searching PubMed and ISI Web of Science databases and secondary referencing qualified for inclusion. A random-effects model was used to calculate the summary odds ratios (OR) and their corresponding 95% confidence intervals (CIs). For green tea, the summary OR of PCa indicated a borderline significant association in Asian populations for highest green tea consumption vs. non/lowest (OR = 0.62; 95% CI: 0.38-1.01); and the pooled estimate reached statistically significant level for case-control studies (OR = 0.43; 95% CI: 0.25-0.73), but not for prospective cohort studies (OR = 1.00; 95% CI: 0.66-1.53). For black tea, no statistically significant association was observed for the highest vs. non/lowest black tea consumption (OR = 0.99; 95% CI: 0.82-1.20). In conclusion, this meta-analysis supported that green tea but not black tea may have a protective effect on PCa, especially in Asian populations. Further research regarding green tea consumption across different regions apart from Asia is needed.     

Significance of genetic polymorphisms in glutathione S-transferase multigene family and lung cancer risk

A vast number of studies are focused on investigating genetic polymorphism in order to estimate genetic contribution to the development of cancer. Possible cancer susceptibility genes have been sought among oncogenes, tumor suppressor genes, DNA repair genes and genes encoding phase I and phase II enzymes. Large individual differences in the biotransformation of xenobiotics have been explained on the basis of genetic polymorphisms in some detoxifying enzymes, regardless of environmental and occupational exposure. Among these enzymes, glutathione S-transferases (GST) constitute a large multigene family of phase II enzymes involved in detoxification of potentially genotoxic chemicals. Five genetic polymorphisms of GST have been well documented. Total or partial deletions and (or) single nucleotide polymorphisms in alleles encoding GSTM1, GSTM3, GSTPI, GSTT1, GSTZ1 are associated with reduction of enzymatic activity toward several substrates of different GST isoenzymes. In addition, molecular epidemiology studies indicate that a single genetic polymorphism of glutathione S-transferase appears to be a moderate lung cancer risk factor. However, the risk is higher when interactions with more GST polymorphisms and other risk factors (e.g. cigarette smoking) occur. Individuals with decreased rate of detoxification, with "high risk" glutathione S-transferase genotypes have a slightly higher level of carcinogen-DNA adducts and more cytogenetic damages.     

Green tea consumption and prostate cancer risk in Japanese men: a prospective study

The incidence of prostate cancer is much lower in Asian than Western populations. Given that environmental factors such as dietary habits may play a major role in the causation of prostate cancer and the high consumption of green tea in Asian populations, this low incidence may be partly due to the effects of green tea. The JPHC Study (Japan Public Health Center-based Prospective Study) was established in 1990 for cohort I and in 1993 for cohort II. The subjects were 49,920 men aged 40-69 years who completed a questionnaire that included their green tea consumption habit at baseline and were followed until the end of 2004. During this time, 404 men were newly diagnosed with prostate cancer, of whom 114 had advanced cases, 271 were localized, and 19 were of an undetermined stage. Green tea was not associated with localized prostate cancer. However, consumption was associated with a dose-dependent decrease in the risk of advanced prostate cancer. The multivariate relative risk was 0.52 (95% confidence interval: 0.28, 0.96) for men drinking 5 or more cups/day compared with less than 1 cup/day (p(trend) = 0.01). Green tea may be associated with a decreased risk of advanced prostate cancer.     

绿茶与子宫内膜癌关系的病例对照研究

目的探讨饮茶特别是绿茶与子宫内膜癌的关系。方法采用以人群为基础的病例对照研究,调查上海市1997年1月至2002年12月间已确诊年龄30～69岁的子宫内膜癌患者(n=995)和全人群对照(n=1087)的一般情况、月经生育史、饮食及营养素、个人生活习惯、激素相关因素、疾病及家族史等资料,采用非条件logistic回归模型分析饮茶与子宫内膜癌的关系。结果与从未饮茶者相比,有饮茶史者患子宫内膜癌的危险略降低(OR=0.82,P=0.0466)。饮茶主要对绝经前女性有保护作用(OR=0.74,95%CI:0.54～1.01);以从不饮茶者为参比组,饮淡茶、浓淡适中及浓茶者的OR值分别为0.72、0.88和0.44,趋势检验有统计学意义(P=0.0431)。在不吸烟不饮酒者中,饮绿茶对子宫内膜癌有保护作用(OR=0.77,P=0.0199);每周饮绿茶频率越高,患子宫内膜癌的危险性越低;以从未饮茶者为参比组,每周饮绿茶<7次及≥7次者OR值分别为0.90(95%CI:0.53～1.54)和0.76(95%CI:0.60～0.95),趋势检验P=0.0163;饮绿茶量越大危险性越低,每月饮绿茶≤100g、～200g及>200g者的OR值分别为0.76、0.87和0.74,趋势检验有统计学意义。结论饮茶特别是绿茶对子宫内膜癌可能有弱的保护作用,且该作用可能局限于绝经前女性。     

饮茶与肺癌发病风险的病例-对照研究

目的探讨饮茶与肺癌的关联。方法采用病例对照研究设计,收集确诊的肺癌新发病例1225例和按频数匹配的健康对照1234例。采用统一编制的调查表,面访收集研究对象的一般人口学特征、居住环境、饮食史、吸烟史、饮酒史、饮茶史、疾病及家族史等资料。非条件logistic回归模型估算饮茶与肺癌发病风险的调整比值比(OR)及其95%可信区间(95%CI),并分析饮茶与吸烟的交互作用。结果饮茶可显著降低非吸烟者肺癌的发病风险,调整OR值为0.465(95%CI 0.345～0.625);随着饮茶年数的增加,肺癌发生的危险性降低;红茶、绿茶、乌龙茶、其他类型茶的调整OR值分别为0.333(95%CI 0.154～0.720)、0.522(95%CI 0.356～0.767)、0.735(95%CI 0.424～1.274)和0.267(95%CI 0.143～0.497)。每周饮茶<3次和饮淡茶者与吸烟者肺癌有显著关联(P<0.05),调整OR值分别为0.453(95%CI 0.286～0.717)和0.518(95%CI 0.346～0.778)。结论饮茶是肺癌的保护因素,尤其可明显降低非吸烟肺癌的危险性。     

Interaction of soy food and tea consumption with CYP19A1 genetic polymorphisms in the development of endometrial cancer

Certain polyphenols inhibit the activity of aromatase, a critical enzyme in estrogen synthesis that is coded by the CYP19A1 gene. Consumption of polyphenol-rich foods and beverages, thus, may interact with CYP19A1 genetic polymorphisms in the development of endometrial cancer. The authors tested this hypothesis in the Shanghai Endometrial Cancer Study (1997-2003), a population-based case-control study of 1,204 endometrial cancer cases and 1,212 controls. Dietary information was obtained by use of a validated food frequency questionnaire. Genotypes of CYP19A1 at rs28566535, rs1065779, rs752760, rs700519, and rs1870050 were available for 1,042 cases and 1,035 controls. Unconditional logistic regression models were used to calculate odds ratios and their 95% confidence intervals after adjustment for potential confounding factors. Higher intake of soy foods and tea consumption were both inversely associated with the risk of endometrial cancer, with odds ratios of 0.8 (95% confidence interval: 0.6, 1.0) for the highest versus the lowest tertiles of intake of soy and 0.8 (95% confidence interval: 06, 0.9) for ever tea consumption. The association of single nucleotide polymorphisms rs1065779, rs752760, and rs1870050 with endometrial cancer was modified by tea consumption (p(interaction) < 0.05) but not by soy isoflavone intake. The authors' findings suggest that tea polyphenols may modify the effect of CYP19A1 genetic polymorphisms on the development of endometrial cancer.     

谷胱甘肽-S-转移酶M1基因多态与食管癌的Meta分析

目的 对谷胱甘肽-S-转移酶M1(GSTM1)基因多态与食管癌的关联性进行Meta分析。方法 以食管癌组与对照组人群基因型分布的OR值为效应指标,各资料间进行一致性检验,以确定采用固定或随机效应模型进行合并分析。发表偏倚评估用漏斗图法进行。结果 共收集国内外相关资料11篇,积累病例1190例,对照1964名,合并OR值为1.197(95％CI:0.846～1.692)。对其中5篇资料按吸烟与否分层,吸烟组合并OR值为1.523(95％CI:1.099～2.109);不吸烟组合并OR值为0.933(95％CI:0.469～1.692)。结论 GSTM1基因多态与食管癌的易感性无关,但携带GSTM1空白基因型的吸烟者患食管癌的危险性可能会增加。     

Green tea composition, consumption, and polyphenol chemistry.

Tea is grown in about 30 countries but is consumed worldwide, although at greatly varying levels. It is the most widely consumed beverage aside from water with a per capita worldwide consumption of approximately 0.12 liter per year. Tea is manufactured in three basic forms. Green tea is prepared in such a way as to preclude the oxidation of green leaf polyphenols. During black tea production oxidation is promoted so that most of these substances are oxidized. Oolong tea is a partially oxidized product. Of the approximately 2.5 million metric tons of dried tea manufactured, only 20% is green tea and less than 2% is oolong tea. Green tea is consumed primarily in China, Japan, and a few countries in North Africa and the Middle East. Fresh tea leaf is unusually rich in the flavanol group of polyphenols known as catechins which may constitute up to 30% of the dry leaf weight. Other polyphenols include flavanols and their glycosides, and depsides such as chlorogenic acid, coumarylquinic acid, and one unique to tea, theogallin (3-galloylquinic acid). Caffeine is present at an average level of 3% along with very small amounts of the other common methylxanthines, theobromine and theophylline. The amino acid theanine (5-N-ethylglutamine) is also unique to tea. Tea accumulates aluminum and manganese. In addition to the normal complement of plant cell enzymes, tea leaf contains an active polyphenol oxidase which catalyzes the aerobic oxidation of the catechins when the leaf cell structure is disrupted during black tea manufacture. The various quinones produced by the enzymatic oxidations undergo condensation reactions which result in a series of compounds, including bisflavanols, theaflavins, epitheaflavic acids, and thearubigens, which impart the characteristic taste and color properties of black tea. Most of these compounds readily form complexes with caffeine. There is no tannic acid in tea. Thearubigens constitute the largest mass of the extractable matter in black tea but their composition is not well known. Proanthocyanidins make up part of the complex. Tea peroxidase may be involved in their generation. The catechin quinones also initiate the formation of many of the hundreds of volatile compounds found in the black tea aroma fraction. Green tea composition is very similar to that of the fresh leaf except for a few enzymatically catalyzed changes which occur extremely rapidly following plucking. New volatile substances are produced during the drying stage. Oolong tea is intermediate in composition between green and black teas.     

MPO和GSTM1、GSTT1基因多态性与儿童急性白血病易感性分析

目的 探讨髓过氧化物酶（myeloperoxidase,MPO）和谷胱甘肽S-转移酶（glutathione S-transferase,GST） M1、T1基因多态性及其交互作用与儿童急性白血病易感性的关系。方法 155名广东籍儿童急性白血病患者纳入病例组,155健康体检者为对照组。采用巢式聚合酶链式反应检测MPO （G-463A）,GSTT1,GSTM1基因型。采用（口恶）²检验比较各基因型频率在病例组与对照组之间的差异,用OR及95%CI值表示各基因型发生急性白血病的危险度。结果 携带MPO-463位点A突变基因型（GA/AA）可能降低儿童急性白血病发病危险（OR=0.591,95%CI：0.356~0.981,P=0.041）;同时携带GSTT1 null基因和GSTM1 null基因的个体发生发生急性白血病的危险性是同时携带GSTT1 non-null基因和GSTM1non-null基因个体的2.991倍（95%CI：1.578~5.673）;同时携带MPO野生型（GG）基因及GSTT1 null基因和GSTM1 null基因进一步增加发病危险（OR=3.484,95%CI：1.626~7.466,P=0.041）。结论 同时携带MPO野生型（GG）及GSTT1 null基因和GSTM1 null基因的个体发生急性白血病的风险增大,可考虑作为儿童急性白血病易感性的重要生物标志物。     

Effect of acrylamide on chick embryonic liver glutathione S-transferases

Glutathione S-transferases (GSTs, EC 2.5.1.18), as the detoxifying enzymes, play an important protective role in embryonic tissues. The GSTs of eleventh-day chick embryonic liver were purified to electrophoretic homogeneity with an overall yield of 31%. The SDS-PAGE analysis of chick embryonic liver GSTs resolved in to three bands, CL1, CL2 and CL3, with relative molecular weights of 27.0, 26.0 and 25.0 kDa respectively. On 72 hours of treatment with acrylamide (AC) (0.1, 0.2 and 0.3 mg) the specific activities of GSTs with CDNB, pNBC, EPNP, BSP, Δ⁵5A and pNPA increased significantly. Total GPx levels were decreased with CHP in liver samples. Immunoblot analysis of AC-treated liver samples showed a dose-dependent increase in the induction of GSTs. CL1 of theta class, CL2 of Mu class and CL3 of alpha class were induced with AC treatment. The theta, mu and alpha classes induced by AC might inhibit the initiation of carcinogenesis.     

Green tea consumption and serum malondialdehyde-modified LDL concentrations in healthy subjects

OBJECTIVE: Green tea was shown to inhibit LDL oxidation, platelet aggregation, and matrix metalloproteinases (MMPs) activities in vitro. We tried to elucidate whether or not green tea consumption may have these effects in vivo, which may be protective against atherosclerotic disease. METHODS: We measured serum malondialdehyde-modified LDL (MDA-LDL) concentrations and urine 8-epi-prostaglandin (PG) F(2alpha) in 22 healthy male nonsmokers. They drank 7 cups/day of water for 2 weeks and drank 7 cups/day of green tea for the next 2 weeks. Regarding platelet aggregation, plasma thromboxane B(2) (TXB(2)) and 6-keto-PGF(1alpha) concentrations and ex vivo platelet aggregation were evaluated. Plasma MMP-2 and -9 concentrations were also measured. RESULTS: Of the 22 subjects, 20 had been in the habit of drinking green tea before the study. Plasma catechins concentrations significantly decreased at the end of the water period and then increased at the end of the green tea period. Although no change in plasma LDL-cholesterol concentrations (110 +/- 33 vs. 113 +/- 28 mg/dL, p = NS) was found, MDA-LDL concentrations (84 +/- 45 vs. 76 +/- 40 IU/L, p < 0.05) and the ratio of MDA-LDL/LDL-cholesterol (0.74 +/- 0.21 vs. 0.65 +/- 0.20, p < 0.02) significantly decreased at the end of the green tea period. However, no significant changes were observed in urine 8-epi-PGF(2alpha) concentrations, in platelet aggregation, nor in plasma TXB(2), 6-keto-PGF(1alpha) or MMP concentrations. CONCLUSION: Daily consumption of green tea decreased serum MDA-LDL concentrations, but it had no significant effects on platelet aggregation, platelet TX production or plasma MMPs concentrations. Our results suggest that green tea consumption may inhibit LDL oxidation in vivo.     

Cigarette smoking and risk of adult leukemia

A case-control study investigated the relation between cigarette smoking and histologic subtypes of adult leukemia in Missouri in 1984-1990. Among males, elevated risks associated with ever smoking were observed for acute nonlymphocytic leukemia (odds ratio (OR) = 1.5; 95% confidence interval (CI) 1.1-2.0) and acute myelocytic leukemia (OR = 1.5; 95% CI 1.1-2.1). Females also showed an increased risk of acute nonlymphocytic leukemia associated with ever smoking (OR = 1.4; 95% CI 1.0-1.9), with an increasing trend in risk by level of smoking (p less than 0.01). Attributable risk estimates of the proportion of acute nonlymphocytic leukemia caused by smoking were 33 percent in males and 29 percent in females. Elevations in risk were not apparent for chronic forms of leukemia. The findings support the hypothesis that some types of leukemia may be etiologically related to cigarette smoking.     

Black tea consumption and risk of stroke in women and men

PurposeOur aim was examine the association between black tea consumption and risk of total stroke and stroke types in a prospective study.MethodsA total of 74,961 Swedish women and men who were free of cardiovascular disease and cancer at baseline in 1997 were followed up through December 2008. Tea consumption was assessed with a questionnaire at baseline. Stroke cases were ascertained from the Swedish Hospital Discharge Registry.ResultsDuring a mean follow-up of 10.2 years, we ascertained 4089 cases of first stroke, including 3159 cerebral infarctions, 435 intracerebral hemorrhages, 148 subarachnoid hemorrhages, and 347 unspecified strokes. After adjustment for other risk factors, high tea consumption was associated with a significantly lower risk of total stroke; however, there was no dose–response relation (P for trend = .36). Compared with no tea consumption, the multivariable relative risk for four or more cups per day (median, 5) was 0.79 (95% confidence interval [CI], 0.62–0.998). The corresponding relative risks were 0.80 (95% CI, 0.61–1.04) for cerebral infarction and 0.68 (95% CI, 0.35–1.30) for hemorrhagic stroke.ConclusionsThese findings suggest that daily consumption of four or more cups of black tea is inversely associated with risk of stroke.     

Green tea supplementation increases glutathione and plasma antioxidant capacity in adults with the metabolic syndrome

Green tea, a popular polyphenol-containing beverage, has been shown to alleviate clinical features of the metabolic syndrome. However, its effects in endogenous antioxidant biomarkers are not clearly understood. Thus, we tested the hypothesis that green tea supplementation will upregulate antioxidant parameters (enzymatic and nonenzymatic) in adults with the metabolic syndrome. Thirty-five obese participants with the metabolic syndrome were randomly assigned to receive one of the following for 8 weeks: green tea (4 cups per day), control (4 cups water per day), or green tea extract (2 capsules and 4 cups water per day). Blood samples and dietary information were collected at baseline (0 week) and 8 weeks of the study. Circulating carotenoids (α-carotene, β-carotene, lycopene) and tocopherols (α-tocopherol, γ-tocopherol) and trace elements were measured using high-performance liquid chromatography and inductively coupled plasma mass spectroscopy, respectively. Serum antioxidant enzymes (glutathione peroxidase, glutathione, catalase) and plasma antioxidant capacity were measured spectrophotometrically. Green tea beverage and green tea extract significantly increased plasma antioxidant capacity (1.5 to 2.3 μmol/L and 1.2 to 2.5 μmol/L, respectively; P < .05) and whole blood glutathione (1783 to 2395 μg/g hemoglobin and 1905 to 2751 μg/g hemoglobin, respectively; P < .05) vs controls at 8 weeks. No effects were noted in serum levels of carotenoids and tocopherols and glutathione peroxidase and catalase activities. Green tea extract significantly reduced plasma iron vs baseline (128 to 92μg/dL, P < .02), whereas copper, zinc, and selenium were not affected. These results support the hypothesis that green tea may provide antioxidant protection in the metabolic syndrome.     

A review of genetic polymorphisms and prostate cancer risk

In this study, we review a variety of genetic polymorphisms that may have an etiologic role in prostate cancer. We include associations identified in molecular epidemiology studies and the consistency of findings reported to date. Suggestions for further research are also offered. For the purposes of this review, we identified relevant articles through a MEDLINE search for the period of January 1987 through March 2001. The searches were limited to articles published in English. Medical subject headings were used to scan titles, abstracts, and subject headings in the databases using the keywords "prostate neoplasms," "genetics," and "polymorphisms."