Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies

  • Authors:
    • Guangwei Zhu
    • Jin Hua
    • Zhijian Wang
    • Feifei She
    • Yanling Chen
  • View Affiliations

  • Published online on: January 21, 2015     https://doi.org/10.3892/mco.2015.489
  • Pages: 613-618
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Abstract

Previous epidemiological studies investigating the association between tea consumption and the risk of gallbladder cancer have yielded inconsistent results. Therefore, we aimed to assess this association by conducting a meta‑analysis of all available studies. A search was conducted through Pubmed, Embase, Chinese Biomedical Literature Database and China Knowledge Resource Integrated Database to identify relevant studies on tea consumption and the risk of gallbladder cancer. A random‑effects model was used to calculate the overall combined risk estimates. Six studies (4 case‑control and 2 cohort studies), involving a total of 753 patients and 115,349 controls, were included in this meta‑analysis. The overall combined odds ratio (OR) for tea consumption and gallbladder cancer was 0.67 [95% confidence interval (CI): 0.40‑1.12, P=0.13]. Similar results were obtained for the high or moderate tea consumption vs. the low/non‑consumption groups. However, our meta‑analysis identified a significant association between tea consumption and reduced gallbladder cancer risk in women (OR=0.46, 95% CI: 0.26‑0.81, P=0.008), but not in men (OR=0.43, 95% CI: 0.12‑1.59, P=0.21). Therefore, the results of the present meta‑analysis suggest that, according to the currently available epidemiological studies, tea consumption may reduce the risk of gallbladder cancer in women, but not in men. further epidemiological studies are required to determine the association between tea consumption and the risk of gallbladder cancer.

Introduction

Gallbladder cancer is a rare and highly fatal disease and is the most common malignant neoplasm of the extrahepatic biliary tract and the seventh most common gastrointestinal carcinoma (1). There were an estimated 10,310 cases of gallbladder cancer diagnosed in 2013 (2). Although gallbladder cancer remains an uncommon disease, it exhibits a high incidence in certain regions, such as Chile, where it is the most common cause of cancer-related mortality (3). We previously demonstrated the significance of lymph node metastasis (4). Although the etiology of the gallbladder cancer remains unknown, genetic, environmental and infectious factors, as well as the presence of gallstones, are considered to play important roles (5). The majority of the risk factors implicated in the development of gallbladder cancer are associated with inflammation (6).

Tea is one of the most popular beverages worldwide, second only to water, and is obtained from the steamed or pan-fried leaves of Camellia sinensis (7). Tea contains several polyphenols, known as catechins, such as epigallocatechin-3 gallate (EGCG), epigallocatechin (EGC) and epicatechin-3 gallate (ECG), which are considered to prevent the development of certain human diseases (8). Previous cellular and animal xenograft studies have reported that tea or its active components, EGCG, EGC and ECG, may possess antiproliferative, antimutagenic, antioxidant and antibacterial properties (913). In general, tea may prevent multifarious cancers at the cell and animal level. Tea was found to induce the apoptosis of gbc-sd human gallbladder carcinoma cells (14,15).

The results of epidemiological studies, such as cohort and case-control studies, investigating the association between tea consumption and gallbladder cancer risk over the last century, have been inconsistent. Certain studies reported that tea consumption significantly decreased the risk of gallbladder cancer, whereas others reported a non-significant negative correlation (1621). However, to the best of our knowledge, there is currently no published meta-analysis investigating the association between tea consumption and gallbldder cancer risk.

The aim of the present study was to assess the association between tea consumption and the risk of gallbladder cancer through conducting a meta-analysis of relevant case-control and cohort studies.

Materials and methods

Literature search

A literature search was conducted through Pubmed, Embase, Chinese Biomedical literature Database (CBM) and China Knowledge Resource Integrated Database (CNKI), to identify epidemiological studies investigating the association of tea consumption with gallbladder cancer risk. As regards the outcome, the articles were identified using the medical subject headings (mesh) terms ‘gallbladder neoplasm’ or ‘gallbladder carcinoma’ or ‘gallbladder cancer’ and ‘tea’ or ‘polyphenols’. As regards study design, the articles were identified using the mesh terms ‘case-control’ or ‘cohort’ or ‘prospective studies’. The reference lists of the retrieved articles were manually searched to identify potentially relevant publications. All the studies meeting the eligible criteria listed below were included in our meta-analysis.

Inclusion criteria

We reviewed the abstracts of all the identified studies. Further study selection was performed using the following inclusions: i) the exposure of interest was tea consumption; ii) the outcome of interest was gallbladder cancer; iii) the design of the study was cohort, case-control or prospective; and iv) the odds ratio (OR), relative risk or hazard ratio were reported.

The search only involved studies conducted on humans and the publication language was restricted to English and Chinese. If publications were duplicated or shared in more than one study using a different language, we selected the most recent edition and English.

Data extration

Two reviewers (G.W.Z. and J.H.) independently extracted data on the characteristics of the eligible studies retrieved from the databases according to the above mentioned selection criteria, using a standardized data extraction form. The following data were recorded: author name, study design, country, sample size, study period, exposure to tea consumption and study results. Any disagreements were resolved through discussion and consensus with a third author (Z.J.W.).

Statistical analyses

OR with 95% confidence interval (CI) was used as a common measure of the association between tea consumption and the risk of gallbladder cancer across studies. For the purposes of the present analysis, tea consumption was coded as a three-level indicator variable, with non/low, moderate and high consumption (Table I). We investigated possible heterogeneity in the results across the studies using the Cochran's Q test. The I2 statistic, which is a quantitative measure of inconsistency across publications, was also used (22). Studies with an I2 statistic of 25–50, 50–75 and >75% were considered to exhibit low, moderate and high heterogeneity, respectively (22). The random-effects model was used when significant (moderate and high) heterogeneity was observed among studies (23). Potential publication bias was assessed by visually inspecting the Begg's funnel plots. P<0.05 was considered to indicate a statistically significant difference. All the statistical analyses were performed using Review Manager software, version 5.2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark).

Table I.

Characteristics of the studies included in the meta-analysis.

Table I.

Characteristics of the studies included in the meta-analysis.

Study (year)DesignStudy periodCountryNo. of cases/controls Low/non-consumptionModerate consumptionHigh consumption(Refs.)
Nechuta et al (2012)Cohort1996–2000China83/69,310NeverNRCurrent(16)
Yen et al (1987)Case-control1975–1979USA         67/272 Never/occasionally/1–2 cups/day3–4 cups/day≥5 cups/day(17)
Nagano et al (2001)Cohort1979–1994Japan       122/38,5400–1 times/day2–4 times/day≥5 times/day(18)
Zhang et al (2006)Case-control1997–2001China       368/902NeverM: <81,600 g lifetime;M: >81,600 g lifetime;(19)
F: <24,600 g lifetimeF: <24,600 g lifetime
Zatonski et al (1992)Case-control1985–1988Poland        72/184Never<6,570 lifetime drinks>6,570 lifetime drinks(20)
La Vecchia et al (1992)Case-control1983–1990Italy        41/6,141No tea consumptionNRTea consumption(21)

[i] NR, not reported; M, male; F, female.

Results

Identification of relevant studies

Our meta-analysis included a total of 6 studies [4 case-control (17,1921) and 2 cohort studies (16,18)] published between 1987 and 2012. The literature search and selection process is summarized in Fig. 1. The four databases (Pubmed, Embase, CBM and CNKI) and the search through the bibliographies of relevant articles yielded 453 articles. A total of 82 articles were excluded due to being duplicate studies. The remaining 371 articles were reviewed; of these, the majority were excluded following title and abstract review (reviews, letters, or studies not relevant to our meta-analysis were excluded), leaving 10 studies for full-text review. A further 2 studies were excluded [one study with unavailable data for analysis (24) and one study published using English and Chinese (25)]. Following fundamental research exclusion of another 2 studies (14,15), a total of 6 studies were included in our present meta-analysis.

Study characteristics

The characteristics of the 6 studies included in this meta-analysis are summarized in Table I. The case/control sample size of the studies ranged between 41/184 and 368/69,310. Among these studies, 1 study only enrolled a female population (16). The definition of tea consumption level (high/moderate vs. low/non-consumption) are also reported in Table I.

Tea consumption and the risk of gallbladder cancer

A total of 6 studies were included in the meta-analysis investigating the association between tea consumption and the risk of gallbladder cancer. Overall, no significant association was observed between tea consumption and gallbladder cancer risk (OR=0.67, 95% CI: 0.40–1.12, P=0.13) in a random-effects model. There was significant heterogeneity among the studies (I2=82%; P<0.0001) (Fig. 2). Subsequently, sensitivity analyses were conducted to identify the potential source of heterogeneity and to assess the effect of different exclusion criteria on the combined estimates. Exclusion of women from studies on tea and gallbladder cancer risk yielded similar results (OR=0.62, 95% CI: 0.35–1.10, P=0.10), with significant heterogeneity (I2=81%; P=0.0003) (16). Following exclusion of 3 studies with a small sample size, the pooled results were not affected (OR=1.09, 95% CI: 0.80–1.48, P=0.60) and no significant heterogeneity was observed among the remaining studies (I2=0%; P=0.76) (17,19,20).

Levels of tea consumption and gallbladder cancer risk

We performed meta-analyses based on the level of tea consumption to investigate the effect of different tea consumption levels on gallbladder cancer risk. The results were relatively consistent and demonstrated that there was no significant difference bettween high/moderate vs. low/non-consumption in reducing the risk of gallbladder cancer (OR=0.57, 95% CI: 0.25–1.29, P=0.18; Fig. 3A; and OR=0.62, 95% CI: 0.33–1.14, P=0.12; Fig. 3B, respectively).

Comparison of women and men regarding tea consumption and the risk of gallbladder cancer

When studies were divided by gender, there was a significant decrease in the risk of gallbladder cancer associated with tea consumption in women (OR=0.46, 95% CI: 0.26–0.81, P=0.008; Fig. 4A). However, no association between tea consumption and the risk of gallbladder cancer was observed in men (OR=0.43, 95% CI: 0.12–1.59, P=0.21; Fig. 4B).

Publication bias

In our meta-analysis, the potential presence of publication bias was assessed by visual inspection of the Begg's funnel plots, which indicated that there was no significant publication bias (Fig. 5).

Discussion

To the best of our knowledge, this is the first meta-analysis to evaluate the association between tea consumption and gallbladder cancer. This meta-analysis of epidemiological studies (4 case-control and 2 cohort studies) investigating the association between tea and gallbladder cancer risk, demonstrated that tea consumption did not reduce the risk of gallbladder cancer. Similar results were obtained for high or moderate vs. low/non-consumption. However, our meta-analysis identified a significant association between tea consumption and reduced gallbladder cancer risk in women, but not in men. The combined estimates were robust across sensitivity analyses and exhibited no publication bias.

A number of studies conducted in vitro and in vivo reported that tea may protect against different types of cancer (2631). Therefore, several clinical and epidemiological studies were conducted, which, however, yielded conflicting results regarding tea consumption and the risk of breast (32,33), lung (34) and renal cancer (35,36). In order to obtain more convincing results, certain meta-analyses were conducted for other types of cancer, which also yielded inconsistent results (3740).

The results of the epidemiological studies on the association between tea consumption and the risk of gallbladder cancer included in our meta-analysis were inconsistent: 2 studies reported that tea intake decreased the risk of gallbladder cancer (17,20), 3 studies reported opposing results (16,18,21) and 1 study reported that tea intake reduced the risk of gallbladder cancer in women, but not in men (19). Therefore, we performed a meta-analysis assessing the association between tea consumption and gallbladder cancer.

Our meta-analysis found that there was a significant association between tea consumption and reduced gallbladder cancer risk in women, but not in men. There may be a reasonable explanation for this finding: lifestyle factors, such as smoking and alcohol consumption may be responsible for the tea intake not reducing the risk of gallbladder cancer in men, due to the high prevalence of smoking and alcohol consumption among men (41,42), which may eliminate the protective effect of tea. Another possible explanation for the significant protective effect of tea in women may be relevant to the effects of tea on estrogen biosynthesis. Previous studies demonstrated that high levels of estrogens were consistently associated with a high risk of gallbladder cancer in women (4345). Experimental data from animal and cell models suggested that tea may affect estrogen metabolism, although the detailed mechanisms underlying this effect remain unknown (46,47).

As is often the case with meta-analyses, ours had certain limitations. First, our analysis was based on 6 studies with widely variable sample sizes, which may be the origin of the heterogeneity of our meta-analysis. Although we performed a funnel plot for the outcomes, the limited number of studies makes it difficult to explain the result of publication bias. Second, certain detailed information could not be obtained, such as 2 studies that did not provide a precise record of gallbladder cancer cases (16,17), although gallbladder cancer is the most common malignant neoplasm of the extrahepatic biliary tract and accounts for the majority of extrahepatic biliary cancers (1); therefore, the studies were included in our meta-analysis. Moreover, there are several types of tea, including green, oolong and black tea, which may inhibit cancer development through different mechanisms. Therefore, our study results may not apply to all types of tea. Finally, missing and/or unpublished data may lead to bias.

In conclusion, our meta-analysis suggests that, according to the currently available epidemiological studies, tea consumption may reduce the risk of gallbladder cancer in women, but not in men. Due to the limitations of our study, further epidemiological studies are required to determine the association between tea consumption and the risk of gallbladder cancer.

Acknowledgements

This study was supported by grants from the National Natural Science Foundation of China (no. 81272373), the Key Project of Science and Technology Research Program of Fujian Province (no. 2009Y0024), the Key Project of Science Research of Fujian Medical University (no. 09ZD017) and the National Clinical Key Specialty Construction Project (General Surgery) of China.

References

1 

Donohue JH, Stewart AK and Menck HR: The National Cancer Data Base report on carcinoma of the gallbladder, 1989–1995. Cancer. 83:2618–2628. 1998. View Article : Google Scholar : PubMed/NCBI

2 

Siegel R, Naishadham D and Jemal A: Cancer statistics. 2013 CA Cancer J Clin. 63:11–30. 2013. View Article : Google Scholar

3 

Randi G, Malvezzi M, Levi F, et al: Epidemiology of biliary tract cancers: an update. Ann Oncol. 20:146–159. 2009. View Article : Google Scholar : PubMed/NCBI

4 

Du Q, Jiang L, Wang XQ, Pan W, She FF and Chen YL: Establishment of and comparison between orthotopic xenograft and subcutaneous xenograft models of gallbladder carcinoma. Asian Pac J Cancer Prev. 15:3747–3752. 2014. View Article : Google Scholar : PubMed/NCBI

5 

Wernberg JA and Lucarelli DD: Gallbladder cancer. Surg Clin North Am. 94:343–360. 2014. View Article : Google Scholar : PubMed/NCBI

6 

Albores-Saavedra J, Alcantra-Vazquez A, Cruz-Ortiz H and Herrera-Goepfert R: The precursor lesions of invasive gallbladder carcinoma Hyperplasia, atypical hyperplasia and carcinoma in situ. Cancer. 45:919–927. 1980. View Article : Google Scholar : PubMed/NCBI

7 

Jankun J, Selman SH, Swiercz R and Skrzypczak-Jankun E: Why drinking green tea could prevent cancer. Nature. 387:5611997. View Article : Google Scholar : PubMed/NCBI

8 

Reto M, Figueira ME, Filipe HM and Almeida CM: Chemical composition of green tea (Camellia sinensis) infusions commercialized in Portugal. Plant Foods Hum Nutr. 62:139–144. 2007. View Article : Google Scholar : PubMed/NCBI

9 

Jochmann N, Baumann G and Stangl V: Green tea and cardiovascular disease: from molecular targets towards human health. Curr Opin Clin Nutr Metab Care. 11:758–765. 2008. View Article : Google Scholar : PubMed/NCBI

10 

Cheng S, Ding L, Zhen Y, et al: Progress in studies on the antimutagenicity and anticarcinogenicity of green tea epicatechins. Chin Med Sci J. 6:233–238. 1991.PubMed/NCBI

11 

Gupta S, Saha B and Giri AK: Comparative antimutagenic and anticlastogenic effects of green tea and black tea: a review. Mutat Res. 512:37–65. 2002. View Article : Google Scholar : PubMed/NCBI

12 

Lambert JD and Elias RJ: The antioxidant and pro-oxidant activities of green tea polyphenols: a role in cancer prevention. Arch Biochem Biophys. 501:65–72. 2010. View Article : Google Scholar : PubMed/NCBI

13 

Cabrera C, Artacho R and Gimenez R: Beneficial effects of green tea - a review. J Am Coll Nutr. 25:79–99. 2006. View Article : Google Scholar : PubMed/NCBI

14 

Lian CQ, Zhang J and Chen ZD: Changes of free calcium ion concentration and mitochondrial membrane potential during apoptosis of human gallbladder carcinoma GBC-SD cells induced by tea polyphenols. Chin J Biol. 25:449–452. 2012.

15 

Lian CQ, Xia J, Gao Q and Zhang J: A study on apoptosis in human gallbladder carcinoma GBC-SD cells induced by tea polyphenols. Chin J Gerontol. 32:2077–2080. 2012.

16 

Nechuta S, Shu XO, Li HL, et al: Prospective cohort study of tea consumption and risk of digestive system cancers: results from the Shanghai Women's Health Study. Am J Clin Nutr. 96:1056–1063. 2012. View Article : Google Scholar : PubMed/NCBI

17 

Yen S, Hsieh CC and MacMahon B: Extrahepatic bile duct cancer and smoking, beverage consumption, past medical history, and oral contraceptive use. Cancer. 59:2112–2116. 1987. View Article : Google Scholar : PubMed/NCBI

18 

Nagano J, Kono S, Preston DL and Mabuchi K: A prospective study of green tea consumption and cancer incidence, Hiroshima and Nagasaki (Japan). Cancer Causes Control. 12:501–508. 2001. View Article : Google Scholar : PubMed/NCBI

19 

Zhang XH, Andreotti G, Gao YT, et al: Tea drinking and the risk of biliary tract cancers and biliary stones: a population-based case-control study in Shanghai, China. Int J Cancer. 118:3089–3094. 2006. View Article : Google Scholar : PubMed/NCBI

20 

Zatonski WA, La Vecchia C, Przewozniak K, Maisonneuve P, Lowenfels AB and Boyle P: Risk factors for gallbladder cancer: a Polish case-control study. Int J Cancer. 51:707–711. 1992. View Article : Google Scholar : PubMed/NCBI

21 

La Vecchia C, Negri E, Franceschi S, D'Avanzo B and Boyle P: Tea consumption and cancer risk. Nutr Cancer. 17:27–31. 1992. View Article : Google Scholar : PubMed/NCBI

22 

Higgins JP, Thompson SG, Deeks JJ and Altman DG: Measuring inconsistency in meta-analyses. BMJ. 327:557–560. 2003. View Article : Google Scholar : PubMed/NCBI

23 

DerSimonian R and Laird N: Meta-analysis in clinical trials. Control Clin Trials. 7:177–188. 1986. View Article : Google Scholar : PubMed/NCBI

24 

Pandey M and Shukla VK: Diet and gallbladder cancer: a case-control study. Eur J Cancer Prev. 11:365–368. 2002. View Article : Google Scholar : PubMed/NCBI

25 

Zhang XH, Gao YT, Rashid A, et al: Tea consumption and risk of biliary tract cancers and gallstone disease: a population-based case-control study in Shanghai, China. Chin J Oncol. 27:667–671. 2005.(In Chinese).

26 

Yang CS, Maliakal P and Meng X: Inhibition of carcinogenesis by tea. Annu Rev Pharmacol Toxicol. 42:25–54. 2002. View Article : Google Scholar : PubMed/NCBI

27 

Chen D, Daniel KG, Kuhn DJ, et al: Green tea and tea polyphenols in cancer prevention. Front Biosci. 9:2618–2631. 2004. View Article : Google Scholar : PubMed/NCBI

28 

Huo C, Wan SB, Lam WH, et al: The challenge of developing green tea polyphenols as therapeutic agents. Inflammopharmacology. 16:248–252. 2008. View Article : Google Scholar : PubMed/NCBI

29 

Adhami VM, Siddiqui IA, Sarfaraz S, et al: Effective prostate cancer chemopreventive intervention with green tea polyphenols in the TRAMP model depends on the stage of the disease. Clin Cancer Res. 15:1947–1953. 2009. View Article : Google Scholar : PubMed/NCBI

30 

Bettuzzi S, Rizzi F and Belloni L: Clinical relevance of the inhibitory effect of green tea catechins (GtCs) on prostate cancer progression in combination with molecular profiling of catechin-resistant tumors: an integrated view. Pol J Vet Sci. 10:57–60. 2007.PubMed/NCBI

31 

Scaltriti M, Belloni L, Caporali A, et al: Molecular classification of green tea catechin-sensitive and green tea catechin-resistant prostate cancer in the TRAMP mice model by quantitative real-time PCR gene profiling. Carcinogenesis. 27:1047–1053. 2006. View Article : Google Scholar : PubMed/NCBI

32 

Inoue M, Tajima K, Mizutani M, et al: Regular consumption of green tea and the risk of breast cancer recurrence: follow-up study from the Hospital-based Epidemiologic Research Program at Aichi Cancer Center (HERPACC). Japan. Cancer Lett. 167:175–182. 2001. View Article : Google Scholar

33 

Wu AH, Yu MC, Tseng CC, Hankin J and Pike MC: Green tea and risk of breast cancer in Asian Americans. Int J Cancer. 106:574–579. 2003. View Article : Google Scholar : PubMed/NCBI

34 

Arts IC, . A review of the epidemiological evidence on tea, flavonoids, and lung cancer. J Nutr. 138:1561S–1566S. 2008.PubMed/NCBI

35 

De Stefani E, Fierro L, Mendilaharsu M, et al: Meat intake, ‘mate’ drinking and renal cell cancer in Uruguay: a case-control study. Br J Cancer. 78:1239–1243. 1998. View Article : Google Scholar : PubMed/NCBI

36 

Hu J, Mao Y, DesMeules M, Csizmadi I, Friedenreich C and Mery L: Canadian Cancer Registries Epidemiology Research Group: Total fluid and specific beverage intake and risk of renal cell carcinoma in Canada. Cancer Epidemiol. 33:355–362. 2009. View Article : Google Scholar : PubMed/NCBI

37 

Zhong S, Chen Z, Yu X, et al: Tea consumption and leukemia risk: a meta-analysis. Tumour Biol. 35:5205–5212. 2014. View Article : Google Scholar : PubMed/NCBI

38 

Hu ZH, Lin YW, Xu X, et al: No association between tea consumption and risk of renal cell carcinoma: a meta-analysis of epidemiological studies. Asian Pac J Cancer Prev. 14:1691–1695. 2013. View Article : Google Scholar : PubMed/NCBI

39 

Lin YW, Hu ZH, Wang X, et al: Tea consumption and prostate cancer: an updated meta-analysis. World J Surg Oncol. 12:382014. View Article : Google Scholar : PubMed/NCBI

40 

Myung SK, Bae WK, Oh SM, et al: Green tea consumption and risk of stomach cancer: a meta-analysis of epidemiologic studies. Int J Cancer. 124:670–677. 2009. View Article : Google Scholar : PubMed/NCBI

41 

Yuan JM, Sun C and Butler LM: Tea and cancer prevention: epidemiological studies. Pharmacol Res. 64:123–135. 2011. View Article : Google Scholar : PubMed/NCBI

42 

Gao YT, McLaughlin JK, Blot WJ, Ji BT, Dai Q and Fraumeni JF Jr: Reduced risk of esophageal cancer associated with green tea consumption. J Natl Cancer Inst. 86:855–858. 1994. View Article : Google Scholar : PubMed/NCBI

43 

Pandey M and Shukla VK: Lifestyle, parity, menstrual and reproductive factors and risk of gallbladder cancer. Eur J Cancer Prev. 12:269–272. 2003. View Article : Google Scholar : PubMed/NCBI

44 

Nakagaki M and Nakayama F: Effect of female sex hormones on lithogenicity of bile. Jpn J Surg. 12:13–18. 1982. View Article : Google Scholar : PubMed/NCBI

45 

Chen A and Huminer D: The role of estrogen receptors in the development of gallstones and gallbladder cancer. Med Hypotheses. 36:259–260. 1991. View Article : Google Scholar : PubMed/NCBI

46 

Kuruto-Niwa R, Inoue S, Ogawa S, Muramatsu M and Nozawa R: Effects of tea catechins on the ERE-regulated estrogenic activity. J Agric Food Chem. 48:6355–6361. 2000. View Article : Google Scholar : PubMed/NCBI

47 

Nagai M, Conney AH and Zhu BT: Strong inhibitory effects of common tea catechins and bioflavonoids on the O-methylation of catechol estrogens catalyzed by human liver cytosolic catechol-O-methyltransferase. Drug Metab Dispos. 32:497–504. 2004. View Article : Google Scholar : PubMed/NCBI

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Zhu G, Hua J, Wang Z, She F and Chen Y: Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies. Mol Clin Oncol 3: 613-618, 2015.
APA
Zhu, G., Hua, J., Wang, Z., She, F., & Chen, Y. (2015). Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies. Molecular and Clinical Oncology, 3, 613-618. https://doi.org/10.3892/mco.2015.489
MLA
Zhu, G., Hua, J., Wang, Z., She, F., Chen, Y."Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies". Molecular and Clinical Oncology 3.3 (2015): 613-618.
Chicago
Zhu, G., Hua, J., Wang, Z., She, F., Chen, Y."Tea consumption and risk of gallbladder cancer: A meta-analysis of epidemiological studies". Molecular and Clinical Oncology 3, no. 3 (2015): 613-618. https://doi.org/10.3892/mco.2015.489