This article was downloaded by: [Michigan State University] On: 24 February 2015, At: 23:39 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Nutrition and Cancer Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/hnuc20
Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013 a
b
c
d
Xiao-Cui Nie , Dao-Song Dong , Yang Bai & Pu Xia a
Department of Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, China
b
Department of Anesthesiology, The First Affiliated Hospital of China Medical University, Shenyang, China c
Department of Clinical Pharmacology, College of Pharmacy, China Medical University, Shenyang, China d
Click for updates
Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, Shenyang, China Published online: 31 Jul 2014.
To cite this article: Xiao-Cui Nie, Dao-Song Dong, Yang Bai & Pu Xia (2014) Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013, Nutrition and Cancer, 66:6, 1009-1014, DOI: 10.1080/01635581.2014.936947 To link to this article: http://dx.doi.org/10.1080/01635581.2014.936947
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Nutrition and Cancer, 66(6), 1009–1014 Copyright Ó 2014, Taylor & Francis Group, LLC ISSN: 0163-5581 print / 1532-7914 online DOI: 10.1080/01635581.2014.936947
Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013 Xiao-Cui Nie Department of Gynaecology, Shenyang Women’s and Children’s Hospital, Shenyang, China
Dao-Song Dong Department of Anesthesiology, The First Affiliated Hospital of China Medical University, Shenyang, China
Downloaded by [Michigan State University] at 23:39 24 February 2015
Yang Bai Department of Clinical Pharmacology, College of Pharmacy, China Medical University, Shenyang, China
Pu Xia Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, Shenyang, China
Black tea is a commonly consumed beverage in the world, comprising approximately 80% of all tea consumed. We sought to examine the association between black tea consumption and risk of breast cancer, using all available epidemiologic evidence to date. PubMed, EMBASE, ISI Web of Science, Chinese National Knowledge Infrastructure Database, and China Biological Medicine Database were used to search for citations using the MeSH terms as “breast neoplasm” AND “black tea.” Then we performed a meta-analysis of studies of breast cancer risk published between 1985 and 2013 by using RevMan 5.0 software. The results showed that no association between black tea consumption and breast cancer risk in overall [odds ratio (OR) D 0.97; 95% confidence interval (CI) D 0.89–1.05]. We further performed a stratified analysis according to region (United States/Europe). Black tea consumption did not decrease breast cancer risk in the United States (OR D 0.91; 95% CI D 0.78–1.07) and in Europe (OR D 0.99; 95% CI D 0.93–1.06). In addition, the summary OR from all cohort studies (OR D 1.04, 95% CI D 0.91–1.18) or all case-control studies (OR D 0.95, 95% CI D 0.88– 1.02) showed black tea intake has no effects on breast cancer risk. However, the association between black tea consumption and breast cancer incidence remains unclear based on the current
Submitted 16 July 2013; accepted in final form 1 May 2014. Address correspondence to Pu Xia, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, North 2 Road 92#, Heping District, Shenyang City 110001, Liaoning Province, P. R. China. Tele: C86-02423256666. Fax: C86-024-23256666. E-mail: [email protected]
evidence. Further well-designed large studies are needed to confirm our result.
INTRODUCTION Breast cancer is the most frequently diagnosed cancer in females. Worldwide, more than a million women are diagnosed with breast cancer in 2008, accounting for 14% (458,400) of the total cancer deaths (1). Despite advances in early detection and treatment, the incidence of breast cancer is rising in Chinese women according to some hospital-based study for breast cancer (2). Maintaining a healthy body weight, increasing physical activity, and minimizing alcohol intake are the best available strategies to reduce the risk of developing breast cancer (3). Tea is the second most consumed beverage worldwide after water. The vast majority of the tea consumed in the world is black tea, comprising approximately 80% of all tea consumed (4). Black tea contains a mixture of compounds, such as caffeine and gallic acid, that have the potential to influence breast cancer risk and survival (5,6). Over the last 4 decades, a number of epidemiologic studies were conducted to investigate the association between black tea consumption and breast cancer risk. However, the published epidemiologic studies on this topic were carried out separately and the results of these studies were inconsistent with each other. Therefore, in light of the limited and inconsistent body of evidence, we conducted this meta-analysis to determine quantitatively the association between regular intake of black tea and breast cancer risk, combining all available evidence to date. 1009
1010
X.-C. NIE ET AL.
Downloaded by [Michigan State University] at 23:39 24 February 2015
“black tea, flavonoids or catechin,” or keywords “black tea, thearubigin, theaflavin or catechin.” In addition, all bibliographies of retrieved papers were screened for further relevant publications.
Inclusion Criteria To ensure the maximum possible objectivity, the quality of each study was independently assessed by the same two authors (Xiao-Cui Nie and Yang Bai). When discrepancies arose, a third party (Pu Xia) was consulted. For inclusion into the meta-analysis, the identified articles have to provide information on 1) the number of breast cancer cases studied and 20 the odds ratio (OR) or relative risk (RR), and its corresponding 95% confidence interval (CI) for highest vs. non- or lowest level of black tea intake. FIG. 1. Flow diagram of identifying potential studies in our meta-analysis. Records relating to the black tea intake and the breast cancer risk.
METHODS Literature Search Strategy We searched the PubMed, EMBASE, ISI Web of Science, Chinese National Knowledge Infrastructure Database and China Biological Medicine Database to collect all papers associated black tea consumption in relation to breast cancer risk (last search update: June 1, 2013). We identified articles using medical-subject-heading term “breast neoplasm,” or keywords “breast cancer, breast tumor or mammary gland tumor” and
Data extraction Two reviewers (Xiao-Cui Nie and Dao-Song Dong) independently reviewed the articles and extracted the data from all eligible publications according to the criteria listed above. The following information was recorded for each study: first author’s name, year of publication, country of origin, number of cases and controls, and lowest and highest exposure levels. After extraction, data were reviewed and compared by the same two independent investigators. Disagreements between the two extractors were resolved by consensus among the investigators. Additional information concerning a specific
TABLE 1 Characteristics of studies included in the meta-analysis
Country
Design
Study period
Cases/ controls
First author
Year
Ewertz (8) Goldbohm (9) Key (10) McLaughlin (12) Rosenberg (14) Scharier (15) Tavani (17) Wu (18) Zheng (19) Baker (20) Rabstein (21) Pathy (23) Ganmaa (24) Boggs (25) Larsson (26)
1990 Denmark Case-control 1983–1984 1474/1322 1996 Netherland Cohort 1986–1990 507/1376 1999 Japan Cohort 1987–1997 342/34332 1992 USA Case-control 1982–1984 1617/1617 1985 USA Case-control 1975–1982 2645/1476 1987 USA Case-control 1973–1980 1510/1882 1998 Italy Case-control 1983–1994 5882/5399 2003 USA Case-control 1995–1998 501/593 1996 USA Cohort 1986–1993 1015/10056 2006 USA Case-control 1982–1998 398/480 2010 Germany Case-control 2000–2004 1020/1047 2010 Netherlands Cohort 2004–2007 681/27323 2008 USA Cohort 1980–2002 5272/ 1715230 2010 USA Cohort 1995–2007 1268/555852 2009 Sweden Cohort 1987–1990 2952/61433
Lowest exposure level
Highest exposure level
Relative risk (95% confidence interval) for highest vs. lowest level
0
Nutrition and Cancer Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/hnuc20
Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013 a
b
c
d
Xiao-Cui Nie , Dao-Song Dong , Yang Bai & Pu Xia a
Department of Gynaecology, Shenyang Women's and Children's Hospital, Shenyang, China
b
Department of Anesthesiology, The First Affiliated Hospital of China Medical University, Shenyang, China c
Department of Clinical Pharmacology, College of Pharmacy, China Medical University, Shenyang, China d
Click for updates
Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, Shenyang, China Published online: 31 Jul 2014.
To cite this article: Xiao-Cui Nie, Dao-Song Dong, Yang Bai & Pu Xia (2014) Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013, Nutrition and Cancer, 66:6, 1009-1014, DOI: 10.1080/01635581.2014.936947 To link to this article: http://dx.doi.org/10.1080/01635581.2014.936947
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Nutrition and Cancer, 66(6), 1009–1014 Copyright Ó 2014, Taylor & Francis Group, LLC ISSN: 0163-5581 print / 1532-7914 online DOI: 10.1080/01635581.2014.936947
Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013 Xiao-Cui Nie Department of Gynaecology, Shenyang Women’s and Children’s Hospital, Shenyang, China
Dao-Song Dong Department of Anesthesiology, The First Affiliated Hospital of China Medical University, Shenyang, China
Downloaded by [Michigan State University] at 23:39 24 February 2015
Yang Bai Department of Clinical Pharmacology, College of Pharmacy, China Medical University, Shenyang, China
Pu Xia Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, Shenyang, China
Black tea is a commonly consumed beverage in the world, comprising approximately 80% of all tea consumed. We sought to examine the association between black tea consumption and risk of breast cancer, using all available epidemiologic evidence to date. PubMed, EMBASE, ISI Web of Science, Chinese National Knowledge Infrastructure Database, and China Biological Medicine Database were used to search for citations using the MeSH terms as “breast neoplasm” AND “black tea.” Then we performed a meta-analysis of studies of breast cancer risk published between 1985 and 2013 by using RevMan 5.0 software. The results showed that no association between black tea consumption and breast cancer risk in overall [odds ratio (OR) D 0.97; 95% confidence interval (CI) D 0.89–1.05]. We further performed a stratified analysis according to region (United States/Europe). Black tea consumption did not decrease breast cancer risk in the United States (OR D 0.91; 95% CI D 0.78–1.07) and in Europe (OR D 0.99; 95% CI D 0.93–1.06). In addition, the summary OR from all cohort studies (OR D 1.04, 95% CI D 0.91–1.18) or all case-control studies (OR D 0.95, 95% CI D 0.88– 1.02) showed black tea intake has no effects on breast cancer risk. However, the association between black tea consumption and breast cancer incidence remains unclear based on the current
Submitted 16 July 2013; accepted in final form 1 May 2014. Address correspondence to Pu Xia, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, China Medical University, North 2 Road 92#, Heping District, Shenyang City 110001, Liaoning Province, P. R. China. Tele: C86-02423256666. Fax: C86-024-23256666. E-mail: [email protected]
evidence. Further well-designed large studies are needed to confirm our result.
INTRODUCTION Breast cancer is the most frequently diagnosed cancer in females. Worldwide, more than a million women are diagnosed with breast cancer in 2008, accounting for 14% (458,400) of the total cancer deaths (1). Despite advances in early detection and treatment, the incidence of breast cancer is rising in Chinese women according to some hospital-based study for breast cancer (2). Maintaining a healthy body weight, increasing physical activity, and minimizing alcohol intake are the best available strategies to reduce the risk of developing breast cancer (3). Tea is the second most consumed beverage worldwide after water. The vast majority of the tea consumed in the world is black tea, comprising approximately 80% of all tea consumed (4). Black tea contains a mixture of compounds, such as caffeine and gallic acid, that have the potential to influence breast cancer risk and survival (5,6). Over the last 4 decades, a number of epidemiologic studies were conducted to investigate the association between black tea consumption and breast cancer risk. However, the published epidemiologic studies on this topic were carried out separately and the results of these studies were inconsistent with each other. Therefore, in light of the limited and inconsistent body of evidence, we conducted this meta-analysis to determine quantitatively the association between regular intake of black tea and breast cancer risk, combining all available evidence to date. 1009
1010
X.-C. NIE ET AL.
Downloaded by [Michigan State University] at 23:39 24 February 2015
“black tea, flavonoids or catechin,” or keywords “black tea, thearubigin, theaflavin or catechin.” In addition, all bibliographies of retrieved papers were screened for further relevant publications.
Inclusion Criteria To ensure the maximum possible objectivity, the quality of each study was independently assessed by the same two authors (Xiao-Cui Nie and Yang Bai). When discrepancies arose, a third party (Pu Xia) was consulted. For inclusion into the meta-analysis, the identified articles have to provide information on 1) the number of breast cancer cases studied and 20 the odds ratio (OR) or relative risk (RR), and its corresponding 95% confidence interval (CI) for highest vs. non- or lowest level of black tea intake. FIG. 1. Flow diagram of identifying potential studies in our meta-analysis. Records relating to the black tea intake and the breast cancer risk.
METHODS Literature Search Strategy We searched the PubMed, EMBASE, ISI Web of Science, Chinese National Knowledge Infrastructure Database and China Biological Medicine Database to collect all papers associated black tea consumption in relation to breast cancer risk (last search update: June 1, 2013). We identified articles using medical-subject-heading term “breast neoplasm,” or keywords “breast cancer, breast tumor or mammary gland tumor” and
Data extraction Two reviewers (Xiao-Cui Nie and Dao-Song Dong) independently reviewed the articles and extracted the data from all eligible publications according to the criteria listed above. The following information was recorded for each study: first author’s name, year of publication, country of origin, number of cases and controls, and lowest and highest exposure levels. After extraction, data were reviewed and compared by the same two independent investigators. Disagreements between the two extractors were resolved by consensus among the investigators. Additional information concerning a specific
TABLE 1 Characteristics of studies included in the meta-analysis
Country
Design
Study period
Cases/ controls
First author
Year
Ewertz (8) Goldbohm (9) Key (10) McLaughlin (12) Rosenberg (14) Scharier (15) Tavani (17) Wu (18) Zheng (19) Baker (20) Rabstein (21) Pathy (23) Ganmaa (24) Boggs (25) Larsson (26)
1990 Denmark Case-control 1983–1984 1474/1322 1996 Netherland Cohort 1986–1990 507/1376 1999 Japan Cohort 1987–1997 342/34332 1992 USA Case-control 1982–1984 1617/1617 1985 USA Case-control 1975–1982 2645/1476 1987 USA Case-control 1973–1980 1510/1882 1998 Italy Case-control 1983–1994 5882/5399 2003 USA Case-control 1995–1998 501/593 1996 USA Cohort 1986–1993 1015/10056 2006 USA Case-control 1982–1998 398/480 2010 Germany Case-control 2000–2004 1020/1047 2010 Netherlands Cohort 2004–2007 681/27323 2008 USA Cohort 1980–2002 5272/ 1715230 2010 USA Cohort 1995–2007 1268/555852 2009 Sweden Cohort 1987–1990 2952/61433
Lowest exposure level
Highest exposure level
Relative risk (95% confidence interval) for highest vs. lowest level
0
