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Katuwal S, Tapanainen J, Pukkala E. Multivariate analysis of independent roles of socioeconomic status, occupational physical activity, reproductive factors, and postmenopausal hormonal therapy in risk of breast cancer. Breast Cancer Res Treat 2022; 193:495-505. [PMID: 35366162 PMCID: PMC9090885 DOI: 10.1007/s10549-022-06571-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 03/12/2022] [Indexed: 11/24/2022]
Abstract
PURPOSE This case-control study assesses the independent roles of reproductive history, postmenopausal hormonal therapy (HT), socioeconomic status (SES), and occupational physical activity on the risk of breast cancer (BC). METHODS Odds ratios (OR) were estimated from conditional logistic multivariate regression model in a data set of 19,253 Finnish women diagnosed with BC between 1994 and 2013 and 96,265 age-matched population controls. RESULTS Both pre- and postmenopausal white-collar workers had significantly increased risk of ductal and lobular BC as compared to manual workers. Moderate occupational physical activity reduced risk of lobular BC by 14%. There was a transient increase in the risk of BC observed after each birth followed by a protective effect starting some years after the delivery. As the number of children increased, the short-term excess risk was lower and protective effect was observed earlier. Continuous estrogen-progestin therapy (EPT) significantly increased the risk of both ductal and lobular BC and the magnitude of risk was directly proportional to duration of use (OR for 5+ years of use 2.26, 95% confidence interval 2.12-2.42). Monthly EPT for 5+ years increased the risk (OR 1.32, 95% CI 1.20-1.45). Users of estradiol plus levonorgestrel intrauterine system devices showed ORs of 1.56 (95% CI 1.45-1.69) and 2.18 (95% CI 1.81-2.64) for ductal and lobular BC, respectively. CONCLUSION This study concludes that pregnancy has a dual effect on BC risk, with a transient increase in risk followed by a long-term protective effect. The SES and HT have a large effect on BC risk while occupational physical activity has only a small independent effect.
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Affiliation(s)
- Sushmita Katuwal
- Faculty of Social Sciences, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland.
| | - Juha Tapanainen
- Department of Obstetrics and Gynecology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland.,Department of Obstetrics and Gynecology, PEDEGO Research Unit, Medical Research Center, Oulu University Hospital, University of Oulu, Oulu, Finland
| | - Eero Pukkala
- Faculty of Social Sciences, Tampere University, Arvo Ylpön katu 34, 33520, Tampere, Finland.,Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland
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2
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Impact of Birth Cohorts in Breast Cancer Risk Among South Korean Women. Cancer Nurs 2021; 44:281-287. [PMID: 32022783 DOI: 10.1097/ncc.0000000000000795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND The incidence of breast cancer among South Korean women, a historically low-risk population, has increased over the past 3 decades, with marked changes in socioeconomic environment by birth cohort. OBJECTIVES We investigated associations between breast cancer risk and reproductive factors as well as the impact of birth cohort in those associations. METHOD This was a cross-sectional study of data from the Korea National Health and Nutrition Examination Survey for 2013-2016. Data from 10 012 parous women 30 years or older were analyzed using descriptive statistics and Cox multivariate regression after adjusting for socioeconomic status, educational level, occupation, and birth cohort. RESULTS Of the reproductive factors considered-age at menarche, number of pregnancies, age at first birth, age at last birth, breastfeeding duration, and use of oral contraceptives-only age at menarche was associated with breast cancer risk. Higher educational level, not having an occupation, and younger birth cohort were also associated with increased risk of breast cancer, with birth cohort the strongest of these impact factors. CONCLUSION Whereas the relationship between reproductive factors and breast cancer risk was relatively weak, birth cohort was the most important risk factor for breast cancer. IMPLICATIONS FOR PRACTICE The results provide a basis and a rationale for developing birth cohort-based clinical guidelines for breast cancer prevention and early detection, treatment, and survivorship. These findings should also be useful to researchers in other countries experiencing rapid changes in breast cancer incidence.
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Breast Cancer Characteristics in the Population of Survivors Participating in the World Trade Center Environmental Health Center Program 2002-2019. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18147555. [PMID: 34300003 PMCID: PMC8306152 DOI: 10.3390/ijerph18147555] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/01/2021] [Accepted: 07/13/2021] [Indexed: 11/27/2022]
Abstract
The destruction of World Trade Center on 11 September 2001 exposed local community members to a complex mixture of known carcinogens and potentially carcinogenic substances. To date, breast cancer has not been characterized in detail in the WTC-exposed civilian populations. The cancer characteristics of breast cancer patients were derived from the newly developed Pan-Cancer Database at the WTC Environmental Health Center (WTC EHC). We used the Surveillance, Epidemiology, and End Results (SEER) Program breast cancer data as a reference source. Between May 2002 and 31 December 2019, 2840 persons were diagnosed with any type of cancer at the WTC EHC, including 601 patients with a primary breast cancer diagnosis (592 women and 9 men). There was a higher proportion of grade 3 (poorly differentiated) tumors (34%) among the WTC EHC female breast cancers compared to that of the SEER-18 data (25%). Compared to that of the SEER data, female breast cancers in the WTC EHC had a lower proportion of luminal A (88% and 65%, respectively), higher proportion of luminal B (13% and 15%, respectively), and HER-2-enriched (5.5% and 7%, respectively) subtypes. These findings suggest considerable differences in the breast cancer characteristics and distribution of breast cancer intrinsic subtypes in the WTC-exposed civilian population compared to that of the general population. This is important because of the known effect of molecular subtypes on breast cancer prognosis.
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Rosskamp M, Verbeeck J, Gadeyne S, Verdoodt F, De Schutter H. Socio-Economic Position, Cancer Incidence and Stage at Diagnosis: A Nationwide Cohort Study in Belgium. Cancers (Basel) 2021; 13:cancers13050933. [PMID: 33668089 PMCID: PMC7956180 DOI: 10.3390/cancers13050933] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/16/2021] [Accepted: 02/18/2021] [Indexed: 12/24/2022] Open
Abstract
Background: Socio-economic position is associated with cancer incidence, but the direction and magnitude of this relationship differs across cancer types, geographical regions, and socio-economic parameters. In this nationwide cohort study, we evaluated the association between different individual-level socio-economic and -demographic factors, cancer incidence, and stage at diagnosis in Belgium. Methods: The 2001 census was linked to the nationwide Belgian Cancer Registry for cancer diagnoses between 2004 and 2013. Socio-economic parameters included education level, household composition, and housing conditions. Incidence rate ratios were assessed through Poisson regression models. Stage-specific analyses were conducted through logistic regression models. Results: Deprived groups showed higher risks for lung cancer and head and neck cancers, whereas an inverse relation was observed for malignant melanoma and female breast cancer. Typically, associations were more pronounced in men than in women. A lower socio-economic position was associated with reduced chances of being diagnosed with known or early stage at diagnosis; the strongest disparities were found for male lung cancer and female breast cancer. Conclusions: This study identified population groups at increased risk of cancer and unknown or advanced stage at diagnosis in Belgium. Further investigation is needed to build a comprehensive picture of socio-economic inequality in cancer incidence.
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Affiliation(s)
- Michael Rosskamp
- Belgian Cancer Registry, Rue Royale 215, B-1210 Brussels, Belgium; (J.V.); (F.V.); (H.D.S.)
- Correspondence: ; Tel.: +32-2-250-1010
| | - Julie Verbeeck
- Belgian Cancer Registry, Rue Royale 215, B-1210 Brussels, Belgium; (J.V.); (F.V.); (H.D.S.)
| | - Sylvie Gadeyne
- Sociology Department, Interface Demography, Vrije Universiteit Brussel, Pleinlaan 5, B-1050 Brussels, Belgium;
| | - Freija Verdoodt
- Belgian Cancer Registry, Rue Royale 215, B-1210 Brussels, Belgium; (J.V.); (F.V.); (H.D.S.)
| | - Harlinde De Schutter
- Belgian Cancer Registry, Rue Royale 215, B-1210 Brussels, Belgium; (J.V.); (F.V.); (H.D.S.)
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5
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Berger E, Maitre N, Romana Mancini F, Baglietto L, Perduca V, Colineaux H, Sieri S, Panico S, Sacerdote C, Tumino R, Vineis P, Boutron-Ruault MC, Severi G, Castagné R, Delpierre C. The impact of lifecourse socio-economic position and individual social mobility on breast cancer risk. BMC Cancer 2020; 20:1138. [PMID: 33228587 PMCID: PMC7684912 DOI: 10.1186/s12885-020-07648-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 11/17/2020] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Women with an advantaged socioeconomic position (SEP) have a higher risk of developing breast cancer (BC). The reasons for this association do not seem to be limited to reproductive factors and remain to be understood. We aimed to investigate the impact of lifecourse SEP from childhood and social mobility on the risk of BC considering a broad set of potential mediators. METHODS We used a discovery-replication strategy in two European prospective cohorts, E3N (N = 83,436) and EPIC-Italy (N = 20,530). In E3N, 7877 women were diagnosed with BC during a median 24.4 years of follow-up, while in EPIC-Italy, 893 BC cases were diagnosed within 15.1 years. Hazard ratios (HR) were estimated using Cox proportional hazard models on imputed data. RESULTS In E3N, women with higher education had a higher risk of BC (HR [95%CI] = 1.21 [1.12, 1.30]). This association was attenuated by adjusting for reproductive factors, in particular age at first childbirth (HR[95%CI] = 1.13 [1.04, 1.22]). Health behaviours, anthropometric variables, and BC screening had a weaker effect on the association. Women who remained in a stable advantaged SEP had a higher risk of BC (HR [95%CI] = 1.24 [1.07; 1.43]) attenuated after adjustment for potential mediators (HR [95%CI] = 1.13 [0.98; 1.31]). These results were replicated in EPIC-Italy. CONCLUSIONS These results confirm the important role of reproductive factors in the social gradient in BC risk, which does not appear to be fully explained by the large set of potential mediators, including cancer screening, suggesting that further research is needed to identify additional mechanisms.
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Affiliation(s)
- Eloïse Berger
- UMR LEASP, Université de Toulouse III, UPS, Inserm, Toulouse, France.
| | - Noële Maitre
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
| | - Francesca Romana Mancini
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
| | - Laura Baglietto
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Vittorio Perduca
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
- Université de Paris, CNRS, MAP5 UMR 8145, F-75006, Paris, France
| | - Hélène Colineaux
- UMR LEASP, Université de Toulouse III, UPS, Inserm, Toulouse, France
- Epidemiology Department, Toulouse Teaching Hospital, Toulouse, France
| | - Sabina Sieri
- Epidemiology and Prevention Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Salvatore Panico
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Carlotta Sacerdote
- Unit of Cancer Epidemiology, Città della Salute e della Scienza University-Hospital and Center for Cancer Prevention (CPO), Turin, Italy
| | - Rosario Tumino
- Cancer Registry and Histopathology Department, Provicial Health Authority (ASP) Ragusa, Ragusa, Italy
| | - Paolo Vineis
- Department of Epidemiology and Biostatistics, Imperial College London, MRC-PHE Centre for Environment and Health, School of Public Health, London, UK
- Italian Institute for Genomic Medicine, Torino, Italy
| | - Marie-Christine Boutron-Ruault
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
| | - Gianluca Severi
- CESP, Faculté de Médecine, Université Paris-Saclay, UVSQ, INSERM, Villejuif, France
- Gustave Roussy, F-94805, Villejuif, France
- Department of Statistics, Computer Science and Applications "G. Parenti" (DISIA), University of Florence, Florence, Italy
| | - Raphaële Castagné
- UMR LEASP, Université de Toulouse III, UPS, Inserm, Toulouse, France
| | - Cyrille Delpierre
- UMR LEASP, Université de Toulouse III, UPS, Inserm, Toulouse, France
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Socioeconomic inequalities in cancer incidence in Europe: a comprehensive review of population-based epidemiological studies. Radiol Oncol 2020; 54:1-13. [PMID: 32074075 PMCID: PMC7087422 DOI: 10.2478/raon-2020-0008] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 02/05/2020] [Indexed: 02/08/2023] Open
Abstract
Background Since the end of the previous century, there has not been a comprehensive review of European studies on socioeconomic inequality in cancer incidence. In view of recent advances in data source linkage and analytical methods, we aimed to update the knowledge base on associations between location-specific cancer incidence and individual or area-level measures of socio-economic status (SES) among European adults. Materials and methods We systematically searched three databases (PubMed, Scopus and Web of Science) for articles on cancer incidence and SES. Qualitative synthesis was performed on the 91 included English language studies, published between 2000 and 2019 in Europe, which focused on adults, relied on cancer registry data and reported on relative risk (RR) estimates. Results Adults with low SES have increased risk of head and neck, oesophagogastric, liver and gallbladder, pancreatic, lung, kidney, bladder, penile and cervical cancers (highest RRs for lung, head and neck, stomach and cervix). Conversely, high SES is linked with increased risk of thyroid, breast, prostate and skin cancers. Central nervous system and haematological cancers are not associated with SES. The positive gap in testicular cancer has narrowed, while colorectal cancer shows a varying pattern in different countries. Negative associations are generally stronger for men compared to women. Conclusions In Europe, cancers in almost all common locations are associated with SES and the inequalities can be explained to a varying degree by known life-style related factors, most notably smoking. Independent effects of many individual and area SES measures which capture different aspects of SES can also be observed.
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7
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Suur-Uski J, Pekkala J, Blomgren J, Pietiläinen O, Rahkonen O, Mänty M. Occupational Class Differences in Long-Term Sickness Absence Due to Breast Cancer during 2005-2013: A Population-Based Study among Finnish Women. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E3477. [PMID: 31540506 PMCID: PMC6766186 DOI: 10.3390/ijerph16183477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/12/2019] [Accepted: 09/15/2019] [Indexed: 01/04/2023]
Abstract
Breast cancer is the most common cancer among women in Western countries with clear socioeconomic differences. Higher occupational class is associated with higher breast cancer incidence but with better survival from the disease, whereas lower occupational class is associated with higher risk of sickness absence. We are not aware of previous studies examining changes over time in occupational class differences in sickness absence due to breast cancer. This paper focuses on occupational class differences in the incidence and duration of sickness absence due to breast cancer over the period of 2005-2013. Age-adjusted occupational class differences in the cumulative incidence and duration of sickness absence due to breast cancer were calculated utilising a nationally representative 70% random sample of employed Finnish women aged 35-64 years (yearly N varying between 499,778 and 519,318). The results show that higher occupational class was associated with higher annual cumulative incidence of sickness absence due to breast cancer. Lower occupational class was associated with longer duration of absence. Occupational class differences in both cumulative incidence and duration of absence remained broadly stable. As a conclusion, these results suggest that measures should be targeted particularly to promotion of work capacity among employees with breast cancer in lower occupational classes.
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Affiliation(s)
- Johanna Suur-Uski
- Department of Public Health, University of Helsinki, FIN-00014 Helsinki, Finland.
| | - Johanna Pekkala
- Department of Public Health, University of Helsinki, FIN-00014 Helsinki, Finland.
| | - Jenni Blomgren
- The Social Insurance Institution of Finland, FIN-00100 Helsinki, Finland.
| | - Olli Pietiläinen
- Department of Public Health, University of Helsinki, FIN-00014 Helsinki, Finland.
| | - Ossi Rahkonen
- Department of Public Health, University of Helsinki, FIN-00014 Helsinki, Finland.
| | - Minna Mänty
- Department of Public Health, University of Helsinki, FIN-00014 Helsinki, Finland.
- Department of Research, Development and InnovationLaurea University of Applied Sciences, City of Vantaa, FIN 01200 Vantaa, Finland.
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8
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Husby A, Wohlfahrt J, Øyen N, Melbye M. Pregnancy duration and breast cancer risk. Nat Commun 2018; 9:4255. [PMID: 30353005 PMCID: PMC6199327 DOI: 10.1038/s41467-018-06748-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 09/20/2018] [Indexed: 12/29/2022] Open
Abstract
Full-term pregnancies reduce a woman’s long-term breast cancer risk, while abortions have been shown to have no effect. The precise minimal duration of pregnancy necessary to lower a woman’s breast cancer risk is, however, unknown. Here we provide evidence which point to the protective effect of pregnancy on breast cancer risk arising precisely at the 34th pregnancy week. Using a cohort of 2.3 million Danish women, we found the reduction in breast cancer risk was not observed for pregnancies lasting 33 weeks or less, but restricted to those pregnancies lasting 34 weeks or longer. We further found that parity, socioeconomic status, and vital status of the child at birth did not explain the association, and also replicated our finding in data from 1.6 million women in Norway. We suggest that a distinct biological effect introduced around week 34 of pregnancy holds the key to understand pregnancy-associated breast cancer protection. It is known that full-term pregnancies can reduce a woman’s breast cancer risk. Here, the authors interrogate data from 2.3 million Danish women, showing that this protective effect arises at precisely the 34th week of the pregnancy, and replicated this finding in 1.6 million women from Norway.
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Affiliation(s)
- Anders Husby
- Department of Epidemiology Research, Statens Serum Institut, DK-2300, Copenhagen, Denmark.,Department of Biomedical Data Science, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Jan Wohlfahrt
- Department of Epidemiology Research, Statens Serum Institut, DK-2300, Copenhagen, Denmark
| | - Nina Øyen
- Department of Epidemiology Research, Statens Serum Institut, DK-2300, Copenhagen, Denmark.,Department of Global Public Health and Primary Care, Faculty of Medicine, University of Bergen, N-5020, Bergen, Norway.,Department of Medical Genetics, Haukeland University Hospital, N-5021, Bergen, Norway
| | - Mads Melbye
- Department of Epidemiology Research, Statens Serum Institut, DK-2300, Copenhagen, Denmark. .,Department of Clinical Medicine, University of Copenhagen, DK-2100, Copenhagen, Denmark. .,Department of Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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9
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Trewin CB, Strand BH, Weedon-Fekjær H, Ursin G. Changing patterns of breast cancer incidence and mortality by education level over four decades in Norway, 1971-2009. Eur J Public Health 2018; 27:160-166. [PMID: 28177482 DOI: 10.1093/eurpub/ckw148] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Background In the last century, breast cancer incidence and mortality was higher among higher versus lower educated women in developed countries. Post-millennium, incidence rates have flattened off and mortality declined. We examined breast cancer trends by education level, to see whether recent improvements in incidence and mortality rates have occurred in all education groups. Methods We linked individual registry data on female Norwegian inhabitants aged 35 years and over during 1971–2009. Using Poisson models, we calculated absolute and relative educational differences in age-standardised breast cancer incidence and mortality over four decades. We estimated educational differences by Slope and Relative Index of Inequality, which correspond to rate difference and rate ratio, comparing the highest to lowest educated women. Results Pre-millennium, incidence and mortality of breast cancer were significantly higher in higher versus lower educated women. Post-millennium, educational differences in breast cancer incidence and mortality attenuated. During 2000–2009, breast cancer incidence was still 38% higher for higher versus lower educated women (Relative Index of Inequality: 1.38, 95% confidence interval: 1.31–1.44), but mortality no longer varied significantly by education level (Relative Index of Inequality: 1.09, 95% confidence interval: 0.99–1.19). Among women below 50 years, however, the education gradient for mortality reversed, and mortality was 28% lower for the highest versus lowest educated women during 2000–2009 (Relative Index of Inequality: 0.72, 95% confidence interval: 0.51–0.93). Results Post-millennium improvements in breast cancer incidence and mortality have primarily benefited higher educated women. Breast cancer mortality is now highest among the lowest educated women below 50 years.
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Affiliation(s)
- Cassia B Trewin
- Department of Research, Cancer Registry of Norway, Oslo, Norway.,Norwegian Advisory Unit for Women's Health, Oslo University Hospital, Oslo, Norway.,Department of Health and Inequality, Norwegian Institute of Public Health, Oslo, Norway
| | - Bjørn Heine Strand
- Department of Ageing and Health, Norwegian Institute of Public Health, Oslo, Norway.,Department of Community Medicine, Institute of Health and Society, University of Oslo, Oslo, Norway
| | - Harald Weedon-Fekjær
- Oslo Centre for Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway
| | - Giske Ursin
- Cancer Registry of Norway, Institute of Population-based Cancer Research, Oslo, Norway.,Department of Preventative Medicine, University of Southern California, Los Angeles, USA.,Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
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10
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García-Pérez J, Pollán M, Pérez-Gómez B, González-Sánchez M, Cortés Barragán RA, Maqueda Blasco J, González-Galarzo MC, Alba MÁ, van der Haar R, Casas S, Vicente C, Medina P, Ederra M, Santamariña C, Moreno MP, Casanova F, Pedraz-Pingarrón C, Moreo P, Ascunce N, García M, Salas-Trejo D, Sánchez-Contador C, Llobet R, Lope V. Occupation and mammographic density: A population-based study (DDM-Occup). ENVIRONMENTAL RESEARCH 2017; 159:355-361. [PMID: 28843166 DOI: 10.1016/j.envres.2017.08.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 07/21/2017] [Accepted: 08/14/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION High mammographic density is one of the main risk factors for breast cancer. Although several occupations have been associated with breast cancer, there are no previous occupational studies exploring the association with mammographic density. Our objective was to identify occupations associated with high mammographic density in Spanish female workers. METHODS We conducted a population-based cross-sectional study of occupational determinants of high mammographic density in Spain, based on 1476 women, aged 45-68 years, recruited from seven screening centers within the Spanish Breast Cancer Screening Program network. Reproductive, family, personal, and occupational history data were collected. The latest occupation of each woman was collected and coded according to the 1994 National Classification of Occupations. Mammographic density was assessed from the cranio-caudal mammogram of the left breast using a semi-automated computer-assisted tool. Association between mammographic density and occupation was evaluated by using mixed linear regression models, using log-transformed percentage of mammographic density as dependent variable. Models were adjusted for age, body mass index, menopausal status, parity, smoking, alcohol intake, educational level, type of mammography, first-degree relative with breast cancer, and hormonal replacement therapy use. Screening center and professional reader were included as random effects terms. RESULTS Mammographic density was higher, although non-statistically significant, among secondary school teachers (eβ = 1.41; 95%CI = 0.98-2.03) and nurses (eβ = 1.23; 95%CI = 0.96-1.59), whereas workers engaged in the care of people (eβ = 0.81; 95%CI = 0.66-1.00) and housewives (eβ = 0.87; 95%CI = 0.79-0.95) showed an inverse association with mammographic density. A positive trend for every 5 years working as secondary school teachers was also detected (p-value = 0.035). CONCLUSIONS Nurses and secondary school teachers were the occupations with the highest mammographic density in our study, showing the latter a positive trend with duration of employment. Future studies are necessary to confirm if these results are due to chance or are the result of a true association whose causal hypothesis is, for the moment, unknown.
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Affiliation(s)
- Javier García-Pérez
- Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain.
| | - Marina Pollán
- Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain.
| | - Beatriz Pérez-Gómez
- Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain.
| | - Mario González-Sánchez
- Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain.
| | | | - Jerónimo Maqueda Blasco
- Instituto Nacional de Seguridad e Higiene en el Trabajo, Ministerio de Empleo y Seguridad Social, Madrid, Spain.
| | | | - Miguel Ángel Alba
- Área de Higiene Industrial, PREMAP Seguridad y Salud S.L.U., Barcelona, Spain.
| | | | - Silvia Casas
- Programa de Detección Precoz de Cáncer de Mama, Dirección General de Salud Pública y Participación, Palma, Spain.
| | - Cándida Vicente
- Programa de Prevención de Cáncer de Mama, Dirección General de Salud Pública, Valencia, Spain.
| | - Pilar Medina
- Programa de Prevención y Control del Cáncer, Unidad de Biomarcadores y Susceptibilidad, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Institut Català d'Oncologia, L'Hospitalet de Llobregat, Spain.
| | - María Ederra
- Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain; Navarra Breast Cancer Screening Program, Public Health Institute, Pamplona, Spain.
| | - Carmen Santamariña
- Galicia Breast Cancer Screening Program, Regional Authority of Health, Galicia Regional Government, Corunna, Spain.
| | - María Pilar Moreno
- Aragon Breast Cancer Screening Program, Aragon Health Service, Zaragoza, Spain.
| | - Francisco Casanova
- Sección de Promoción de la Salud del Servicio Territorial de Sanidad de Burgos, Dirección General de Salud Pública de la Consejería de Sanidad de Castilla y León, Burgos, Spain.
| | - Carmen Pedraz-Pingarrón
- Sección de Promoción de la Salud del Servicio Territorial de Sanidad de Burgos, Dirección General de Salud Pública de la Consejería de Sanidad de Castilla y León, Burgos, Spain.
| | - Pilar Moreo
- Aragon Breast Cancer Screening Program, Aragon Health Service, Zaragoza, Spain.
| | - Nieves Ascunce
- Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain; Navarra Breast Cancer Screening Program, Public Health Institute, Pamplona, Spain.
| | - Montse García
- Programa de Prevención y Control del Cáncer, Unidad de Biomarcadores y Susceptibilidad, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Institut Català d'Oncologia, L'Hospitalet de Llobregat, Spain.
| | - Dolores Salas-Trejo
- Programa de Prevención de Cáncer de Mama, Dirección General de Salud Pública, Valencia, Spain.
| | - Carmen Sánchez-Contador
- Programa de Detección Precoz de Cáncer de Mama, Dirección General de Salud Pública y Participación, Palma, Spain.
| | - Rafael Llobet
- Institute of Computer Technology, Universitat Politècnica de València, Valencia, Spain.
| | - Virginia Lope
- Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain; Consortium for Biomedical Research in Epidemiology & Public Health (CIBER Epidemiología y Salud Pública - CIBERESP), Spain.
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11
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Kullberg C, Selander J, Albin M, Borgquist S, Manjer J, Gustavsson P. Female white-collar workers remain at higher risk of breast cancer after adjustments for individual risk factors related to reproduction and lifestyle. Occup Environ Med 2017; 74:652-658. [PMID: 28456763 PMCID: PMC5574386 DOI: 10.1136/oemed-2016-104043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 02/14/2017] [Accepted: 03/19/2017] [Indexed: 01/27/2023]
Abstract
Objectives The aim was to investigate the variation in risk of breast cancer between occupational groups with a focus on white-collar and blue-collar workers and to investigate to what extent the differences were explained by risk factors related to reproduction and lifestyle. Methods Between 1991 and 1996, 14 119 women born between 1923 and 1950 and residents of Malmö, Sweden, were included in this cohort study. Individual data on risk factors (eg, age, parity, age at first child, months of breast feeding per child, hormonal replacement therapy, physical activity, alcohol consumption, smoking, height and body mass index) and occupational history were assessed using a questionnaire. First-time diagnoses of invasive breast cancer were identified through the Swedish Cancer Registry up until 31 December 2013. Results A total of 897 women were diagnosed with breast cancer. Analyses adjusted for age showed an increased risk for white-collar workers compared with blue-collar workers and indicated higher risks in the occupational categories: professionals, administrative and bookkeeping than among women in sales, transportation, production and service work. This difference was only marginally attenuated after adjustment for an extensive set of risk factors related to reproduction and lifestyle. Conclusion Reproductive and lifestyle factors explain only a minor part of the increased risk of breast cancer in white-collar workers. Further studies are needed to investigate the remaining factors for the difference in risk between occupational groups.
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Affiliation(s)
- Cecilia Kullberg
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Jenny Selander
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Maria Albin
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.,Centre for Occupational and Environmental Medicine, Stockholms Lans Landsting, Stockholm, Sweden
| | - Signe Borgquist
- Department of Clinical Sciences, Lunds Universitet, Lund, Sweden
| | - Jonas Manjer
- Department of Clinical Sciences, Lunds Universitet, Lund, Sweden.,Department of Surgery, Skåne University Hospital, Malmö, Sweden
| | - Per Gustavsson
- Unit of Occupational Medicine, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.,Centre for Occupational and Environmental Medicine, Stockholms Lans Landsting, Stockholm, Sweden
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12
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Gadeyne S, Menvielle G, Kulhanova I, Bopp M, Deboosere P, Eikemo T, Hoffmann R, Kovács K, Leinsalu M, Martikainen P, Regidor E, Rychtarikova J, Spadea T, Strand B, Trewin C, Wojtyniak B, Mackenbach J. The turn of the gradient? Educational differences in breast cancer mortality in 18 European populations during the 2000s. Int J Cancer 2017; 141:33-44. [DOI: 10.1002/ijc.30685] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 01/31/2017] [Accepted: 02/02/2017] [Indexed: 12/14/2022]
Affiliation(s)
- S. Gadeyne
- Interface Demography, Department of Sociology; Vrij Universiteit Brussel; Brussels Belgium
- Department of Public Health; Erasmus Medical Centre; Rotterdam the Netherlands
| | - G. Menvielle
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Institut Pierre Louis d’épidémiologie et de Santé Publique (IPLESP UMRS 1136); Paris F75012 France
| | - I. Kulhanova
- Department of Public Health; Erasmus Medical Centre; Rotterdam the Netherlands
| | - M. Bopp
- Epidemiology, Biostatistics and Prevention Institute, University of Zürich; Switzerland
| | - P. Deboosere
- Interface Demography, Department of Sociology; Vrij Universiteit Brussel; Brussels Belgium
| | - T.A. Eikemo
- Department of Public Health; Erasmus Medical Centre; Rotterdam the Netherlands
- Department of Sociology and Political Science; Norwegian University of Science and Technology; Trondheim Norway
| | - R. Hoffmann
- Department of Public Health; Erasmus Medical Centre; Rotterdam the Netherlands
| | - K. Kovács
- Hungarian Demographic Research Institute; Budapest Hungary
| | - M. Leinsalu
- Stockholm Centre for Health and Social Change; Södertörn University; Huddinge Sweden
- Department of Epidemiology and Biostatistics; National Institute for Health Development; Tallinn Estonia
| | - P. Martikainen
- Department of Sociology; University of Helsinki; Helsinki Finland
| | - E. Regidor
- Department of Preventive Medicine and Public Health; Universidad Complutense de Madrid; Madrid Spain
| | - J. Rychtarikova
- Department of Demography; Charles University; Prague Czech Republic
| | - T. Spadea
- Epidemiology Unit, Local Health Authority TO3 of Piedmont Region; Italy
| | - B.H. Strand
- Domain for Mental and Physical Health; Norwegian Institute of Public Health; Oslo Norway
| | - C. Trewin
- Domain for Mental and Physical Health; Norwegian Institute of Public Health; Oslo Norway
| | - B. Wojtyniak
- Department of Monitoring and Analyses of Population Health; National Institute of Public Health-National Institute of Hygiene; Warsaw Poland
| | - J.P. Mackenbach
- Department of Public Health; Erasmus Medical Centre; Rotterdam the Netherlands
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13
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Hwang KT, Noh W, Cho SH, Yu J, Park MH, Jeong J, Lee HJ, Kim J, Oh S, Kim YA. Education Level Is a Strong Prognosticator in the Subgroup Aged More Than 50 Years Regardless of the Molecular Subtype of Breast Cancer: A Study Based on the Nationwide Korean Breast Cancer Registry Database. Cancer Res Treat 2017; 49:1114-1126. [PMID: 28161933 PMCID: PMC5654170 DOI: 10.4143/crt.2016.528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/24/2017] [Indexed: 01/18/2023] Open
Abstract
Purpose This study investigated the role of the education level (EL) as a prognostic factor for breast cancer and analyzed the relationship between the EL and various confounding factors. Materials and Methods The data for 64,129 primary breast cancer patients from the Korean Breast Cancer Registry were analyzed. The EL was classified into two groups according to the education period; the high EL group (≥ 12 years) and low EL group (< 12 years). Survival analyses were performed with respect to the overall survival between the two groups. Results A high EL conferred a superior prognosis compared to a low EL in the subgroup aged > 50 years (hazard ratio, 0.626; 95% confidence interval [CI], 0.577 to 0.678) but not in the subgroup aged ≤ 50 years (hazard ratio, 0.941; 95% CI, 0.865 to 1.024). The EL was a significant independent factor in the subgroup aged > 50 years according to multivariate analyses. The high EL group showed more favorable clinicopathologic features and a higher proportion of patients in this group received lumpectomy, radiation therapy, and endocrine therapy. In the high EL group, a higher proportion of patients received chemotherapy in the subgroups with unfavorable clinicopathologic features. The EL was a significant prognosticator across all molecular subtypes of breast cancer. Conclusion The EL is a strong independent prognostic factor for breast cancer in the subgroup aged > 50 years regardless of the molecular subtype, but not in the subgroup aged ≤ 50 years. Favorable clinicopathologic features and active treatments can explain the main causality of the superior prognosis in the high EL group.
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Affiliation(s)
- Ki-Tae Hwang
- Department of Surgery, SMG-SNU Boramae Medical Center, Seoul, Korea
| | - Woochul Noh
- Department of Surgery, Korea Cancer Center Hospital, Seoul, Korea
| | - Se-Heon Cho
- Department of Surgery, Dong-A University Medical Center, Busan, Korea
| | - Jonghan Yu
- Department of Surgery, Samsung Medical Center, Seoul, Korea
| | - Min Ho Park
- Department of Surgery, Chonnam National University Medical School, Gwangju, Korea
| | - Joon Jeong
- Department of Surgery, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | | | - Jongjin Kim
- Department of Surgery, SMG-SNU Boramae Medical Center, Seoul, Korea
| | - Sohee Oh
- Department of Biostatistics, SMG-SNU Boramae Medical Center, Seoul, Korea
| | - Young A Kim
- Department of Pathology, SMG-SNU Boramae Medical Center, Seoul, Korea
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14
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Palme M, Simeonova E. Does women's education affect breast cancer risk and survival? Evidence from a population based social experiment in education. JOURNAL OF HEALTH ECONOMICS 2015; 42:115-124. [PMID: 25912223 DOI: 10.1016/j.jhealeco.2014.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/30/2014] [Accepted: 11/05/2014] [Indexed: 06/04/2023]
Abstract
Breast cancer is a notable exception to the well documented positive education gradient in health. A number of studies have found that highly educated women are more likely to be diagnosed with the disease. Breast cancer is therefore often labeled as a "welfare disease". However, it has not been established whether the strong positive correlation holds up when education is exogenously determined. We estimate the causal effect of education on the probability of being diagnosed with breast cancer by exploiting an education reform that extended compulsory schooling and was implemented as a social experiment. We find that the incidence of breast cancer increased for those exposed to the reform.
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Affiliation(s)
- Mårten Palme
- Department of Economics, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Emilia Simeonova
- Johns Hopkins University and NBER, 100 International Drive, Baltimore, MD 21202, United States.
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15
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Hvidtfeldt UA, Lange T, Andersen I, Diderichsen F, Keiding N, Prescott E, Sørensen TIA, Tjønneland A, Rod NH. Educational differences in postmenopausal breast cancer--quantifying indirect effects through health behaviors, body mass index and reproductive patterns. PLoS One 2013; 8:e78690. [PMID: 24205296 PMCID: PMC3812044 DOI: 10.1371/journal.pone.0078690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 09/14/2013] [Indexed: 01/14/2023] Open
Abstract
Studying mechanisms underlying social inequality in postmenopausal breast cancer is important in order to develop prevention strategies. Standard methods for investigating indirect effects, by comparing crude models to adjusted, are often biased. We applied a new method enabling the decomposition of the effect of educational level on breast cancer incidence into indirect effects through reproductive patterns (parity and age at first birth), body mass index and health behavior (alcohol consumption, physical inactivity, and hormone therapy use). The study was based on a pooled cohort of 6 studies from the Copenhagen area including 33,562 women (1,733 breast cancer cases) aged 50-70 years at baseline. The crude absolute rate of breast cancer was 399 cases per 100,000 person-years. A high educational level compared to low was associated with 74 (95% CI 22-125) extra breast cancer cases per 100,000 person-years at risk. Of these, 26% (95% CI 14%-69%) could be attributed to alcohol consumption. Similar effects were observed for age at first birth (32%; 95% CI 10%-257%), parity (19%; 95%CI 10%-45%), and hormone therapy use (10%; 95% CI 6%-18%). Educational level modified the effect of physical activity on breast cancer. In conclusion, this analysis suggests that a substantial number of the excess postmenopausal breast cancer events among women with a high educational level compared to a low can be attributed to differences in alcohol consumption, use of hormone therapy, and reproductive patterns. Women of high educational level may be more vulnerable to physical inactivity compared to women of low educational level.
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Affiliation(s)
- Ulla Arthur Hvidtfeldt
- Social Medicine Section, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Theis Lange
- Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Ingelise Andersen
- Social Medicine Section, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Finn Diderichsen
- Social Medicine Section, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Niels Keiding
- Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Eva Prescott
- Department of Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark
- The Copenhagen City Heart Study, Bispebjerg University Hospital, Copenhagen, Denmark
| | - Thorkild I. A. Sørensen
- Department of Public Health and The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, and Institute of Preventive Medicine, Bispebjerg and Frederiksberg Hospitals – part of the Copenhagen University Hospital, The Capital Region, Copenhagen, Denmark
| | - Anne Tjønneland
- Institute of Cancer Epidemiology, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Naja Hulvej Rod
- Social Medicine Section, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
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16
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Menvielle G, Rey G, Jougla E, Luce D. Diverging trends in educational inequalities in cancer mortality between men and women in the 2000s in France. BMC Public Health 2013; 13:823. [PMID: 24015917 PMCID: PMC3847008 DOI: 10.1186/1471-2458-13-823] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 09/03/2013] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Socioeconomic inequalities in cancer mortality have been observed in different European countries and the US until the end of the 1990s, with changes over time in the magnitude of these inequalities and contrasted situations between countries. The aim of this study is to estimate relative and absolute educational differences in cancer mortality in France between 1999 and 2007, and to compare these inequalities with those reported during the 1990s. METHODS Data from a representative sample including 1% of the French population were analysed. Educational differences among people aged 30-74 were quantified with hazard ratios and relative indices of inequality (RII) computed using Cox regression models as well as mortality rate difference and population attributable fraction. RESULTS In the period 1999-2007, large relative inequalities were found among men for total cancer and smoking and/or alcohol related cancers mortality (lung, head and neck, oesophagus). Among women, educational differences were reported for total cancer, head and neck and uterus cancer mortality. No association was found between education and breast cancer mortality. Slight educational differences in colorectal cancer mortality were observed in men and women. For most frequent cancers, no change was observed in the magnitude of relative inequalities in mortality between the 1990s and the 2000s, although the RII for lung cancer increased both in men and women. Among women, a large increase in absolute inequalities in mortality was observed for all cancers combined, lung, head and neck and colorectal cancer. In contrast, among men, absolute inequalities in mortality decreased for all smoking and/or alcohol related cancers. CONCLUSION Although social inequalities in cancer mortality are still high among men, an encouraging trend is observed. Among women though, the situation regarding social inequalities is less favourable, mainly due to a health improvement limited to higher educated women. These inequalities may be expected to further increase in future years.
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Affiliation(s)
- Gwenn Menvielle
- Inserm U1018, Center for Epidemiology and Population Health, Occupational and social determinants of health, Bat 15/16 Hôpital Paul Brousse, 16 ave Paul Vaillant Couturier, Villejuif Cedex 94807, France
- University of Versailles Saint Quentin, UMRS 1018, France
| | | | | | - Danièle Luce
- Inserm U1018, Center for Epidemiology and Population Health, Occupational and social determinants of health, Bat 15/16 Hôpital Paul Brousse, 16 ave Paul Vaillant Couturier, Villejuif Cedex 94807, France
- University of Versailles Saint Quentin, UMRS 1018, France
- Inserm U1085, Irset, Pointe-à-Pitre, Guadeloupe, French West Indies
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17
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Pudrovska T, Carr D, McFarland M, Collins C. Higher-status occupations and breast cancer: a life-course stress approach. Soc Sci Med 2013; 89:53-61. [PMID: 23726216 DOI: 10.1016/j.socscimed.2013.04.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 04/07/2013] [Accepted: 04/11/2013] [Indexed: 12/16/2022]
Abstract
Using the 1957-2011 data from 3682 White non-Hispanic women (297 incident breast cancer cases) in the Wisconsin Longitudinal Study, United States, we explore the effect of occupation in 1975 (at age 36) on breast cancer incidence up to age 72. Our study is motivated by the paradoxical association between higher-status occupations and elevated breast cancer risk, which presents a challenge to the consistent health advantage of higher social class. We found that women in professional occupations had 72122% and women in managerial occupations had 57-89% higher risk of a breast cancer diagnosis than housewives and women in lower-status occupations. We explored an estrogen-related pathway (reproductive history, health behaviors, and life-course estrogen cycle) as well as a social stress pathway (occupational experiences) as potential explanations for the effect of higher-status occupations. The elevated risk of breast cancer among professional women was partly explained by estrogen-related variables but remained large and statistically significant. The association between managerial occupations and breast cancer incidence was fully explained by job authority defined as control over others' work. Exercising job authority was related to higher breast cancer risk (HR = 1.57, 95% CI: 1.12, 2.18), especially with longer duration of holding the professional/managerial job. We suggest that the assertion of job authority by women in the 1970s involved stressful interpersonal experiences that may have promoted breast cancer development via prolonged dysregulation of the glucocorticoid system and exposure of the breast tissue to adverse effects of chronically elevated cortisol. Our study emphasizes complex biosocial pathways through which women's gendered occupational experiences become embodied and drive forward physiological repercussions.
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Affiliation(s)
- Tetyana Pudrovska
- Department of Sociology & Crime, Law, and Justice, Population Research Institute, Pennsylvania State University, University Park, PA 16802, USA.
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18
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Gadeyne S, Deboosere P, Vandenheede H, Neels K. Does birth history account for educational differences in breast cancer mortality? A comparison of premenopausal and postmenopausal women in Belgium. Int J Cancer 2012; 131:2878-85. [DOI: 10.1002/ijc.27538] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 01/27/2012] [Indexed: 11/12/2022]
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Abstract
BACKGROUND It has been suggested that reproductive factors may be involved in the etiology of multiple sclerosis (MS). We studied associations of reproductive history with MS risk in a population-based setting. METHODS Using national databases, we established a cohort comprising 4.4 million Danish men and women born between 1935 and 1989 and alive in 1968 or later. We obtained information about their live-born children, pregnancy losses, pregnancy complications, and infertility diagnoses. MS cases in the cohort were identified through 2004 in the Danish Register of Multiple Sclerosis. Associations between reproductive factors and MS risk were evaluated using rate ratios (RRs) obtained in log-linear Poisson regression analysis. RESULTS MS was diagnosed in 6332 women and 3426 men. In both sexes, parents had a lower risk of MS compared with childless persons (in women, RR = 0.76 [95% confidence interval = 0.71-0.82]; in men, 0.89 [0.80-0.98]). RRs were inversely associated with number of children, age at first childbirth, and proximity in time since most recent birth. Among women, MS risk was unrelated to histories of pregnancy loss, pregnancy complications, or infertility. A supplementary analysis in which the date of MS diagnosis was backdated by 5 years to address the possibility of reverse causality did not confirm a protective effect of parenthood (in women, 0.95 [0.88-1.03]; in men, 1.08 [0.98-1.20]). CONCLUSIONS Similar findings in women and men argue against a biologic role of pregnancy in the etiology of MS. Moreover, the observed differences in childbearing patterns were restricted to the 5 years before MS diagnosis, suggesting that reverse causality (ie, reduced reproductive activity in persons with yet-undiagnosed MS) might explain the observed associations.
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Klassen AC, Smith KC. The enduring and evolving relationship between social class and breast cancer burden: a review of the literature. Cancer Epidemiol 2011; 35:217-34. [PMID: 21470929 DOI: 10.1016/j.canep.2011.02.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 01/13/2011] [Accepted: 02/16/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Breast cancer in women has historically been seen as a "cancer of affluence" and there is a well-documented higher incidence among women of higher social class, as well as in societies with higher resources. However, the relationship between social class and breast cancer disease characteristics, especially those associated with poorer prognosis, is less well documented, and the overall relationship between breast cancer mortality and social class has been shown to vary. Furthermore, rapid changes in women's health and health-related behaviors in societies around the world may have an impact on both incidence and mortality patterns for breast cancer in the future. METHODS A PUBMED search on breast cancer and social class (incorporating the MeSH-nested concept of SES) yielded 403 possible studies published between 1978 and 2009, of which 90 met criteria for review. Our review discusses conceptualization and measurement of women's social class in each study, as well as findings related to breast cancer incidence, tumor biology or mortality, associated with social class. FINDINGS We found mostly consistent evidence that breast cancer incidence continues to be higher in higher social class groups, with some modification of risk with adjustment for known risk factors, including physical activity and reproductive history. However, biologic characteristics associated with poorer prognosis were negatively associated with social class (i.e., greater occurrence among disadvantaged women), and mortality from breast cancer showed inconsistent relationship to social class. CONCLUSIONS We discuss these studies in relation to the growing burden of breast cancer among low resource groups and countries, and the need for cancer control strategies reflecting the emerging demographics of breast cancer risk.
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Affiliation(s)
- Ann C Klassen
- Department of Community Health and Prevention, Drexel University School of Public Health, USA.
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21
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Larsen SB, Olsen A, Lynch J, Christensen J, Overvad K, Tjønneland A, Johansen C, Dalton SO. Socioeconomic position and lifestyle in relation to breast cancer incidence among postmenopausal women: a prospective cohort study, Denmark, 1993-2006. Cancer Epidemiol 2011; 35:438-41. [PMID: 21227766 DOI: 10.1016/j.canep.2010.12.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/10/2010] [Accepted: 12/13/2010] [Indexed: 10/18/2022]
Abstract
BACKGROUND In Denmark, the incidence of breast cancer is higher among women with higher socioeconomic position. We investigated whether differences in exposure to certain risk factors contribute to this gradient, as measured from education, income and occupation. METHODS We conducted a cohort study of 23,111 postmenopausal women aged 50-65 years who were enrolled in the prospective Danish 'Diet, Cancer and Health' study between 1993 and 1995. At baseline, all women filled in a questionnaire on lifestyle and food frequency. The results were analysed in Cox proportional hazard models. RESULTS Part of the association with socioeconomic position is due to the potential mediators reproductive pattern, use of hormone replacement therapy and alcohol consumption. After simultaneous adjustment for these factors, the hazard ratios were 1.06 (95% confidence interval [CI], 0.88-1.27) for women with higher education and 1.07 (95% CI, 0.85-1.34) for women with higher income. The HR ratio for women working as higher officials when compared with unskilled workers was 1.23 (0.96-1.59). CONCLUSION The results support the hypothesis that the higher incidence of breast cancer among socially advantaged women is mediated partly by differences in exposure to reproductive factors, hormone replacement therapy and alcohol.
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Affiliation(s)
- Signe Benzon Larsen
- Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen Ø, Denmark.
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Menvielle G, Kunst AE, van Gils CH, Peeters PH, Boshuizen H, Overvad K, Olsen A, Tjonneland A, Hermann S, Kaaks R, Bergmann MM, Illner AK, Lagiou P, Trichopoulos D, Trichopoulou A, Palli D, Berrino F, Mattiello A, Tumino R, Sacerdote C, May A, Monninkhof E, Braaten T, Lund E, Quirós JR, Duell EJ, Sánchez MJ, Navarro C, Ardanaz E, Borgquist S, Manjer J, Khaw KT, Allen NE, Reeves GK, Chajes V, Rinaldi S, Slimani N, Gallo V, Vineis P, Riboli E, Bueno-de-Mesquita HB. The contribution of risk factors to the higher incidence of invasive and in situ breast cancers in women with higher levels of education in the European prospective investigation into cancer and nutrition. Am J Epidemiol 2011; 173:26-37. [PMID: 21084553 PMCID: PMC3320860 DOI: 10.1093/aje/kwq319] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The authors investigated the role of known risk factors in educational differences in breast cancer incidence. Analyses were based on the European Prospective Investigation Into Cancer and Nutrition and included 242,095 women, 433 cases of in situ breast cancer, and 4,469 cases of invasive breast cancer. Reproductive history (age at first full-term pregnancy and parity), exposure to endogenous and exogenous hormones, height, and health behaviors were accounted for in the analyses. Relative indices of inequality (RII) for education were estimated using Cox regression models. A higher risk of invasive breast cancer was found among women with higher levels of education (RII = 1.22, 95% confidence interval (CI): 1.09, 1.37). This association was not observed among nulliparous women (RII = 1.13, 95% CI: 0.84, 1.52). Inequalities in breast cancer incidence decreased substantially after adjusting for reproductive history (RII = 1.11, 95% CI: 0.98, 1.25), with most of the association being explained by age at first full-term pregnancy. Each other risk factor explained a small additional part of the inequalities in breast cancer incidence. Height accounted for most of the remaining differences in incidence. After adjusting for all known risk factors, the authors found no association between education level and risk of invasive breast cancer. Inequalities in incidence were more pronounced for in situ breast cancer, and those inequalities remained after adjustment for all known risk factors (RII = 1.61, 95% CI: 1.07, 2.41), especially among nulliparous women.
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Affiliation(s)
- Gwenn Menvielle
- National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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23
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Abstract
The objective of this study was to investigate the relationship between cancer incidence and socioeconomic status, and to examine the temporal trends in social inequalities in cancer risk. Educational differentials in the incidence of cancer (25 sites) among adult residents of Turin (Italy) were examined using data from the Turin Longitudinal Study and the Piedmont Cancer Registry. The relationship between cancer incidence and educational level was evaluated over three 5-year periods between 1985 and 1999 using Poisson models. An estimated 17% of malignancies among men in the low-educational group were attributable to education, whereas women with a low educational level were slightly protected. Less-educated men had higher risks of upper aero-digestive tract, stomach, lung, liver, rectal, bladder, central nervous system and ill-defined cancers, and lower risks of melanoma, kidney and prostate cancers. Women with lower educational levels were at higher risk of stomach, liver and cervical cancers, whereas they were less likely to be diagnosed with melanoma, ovarian and breast cancers. For most sites, the educational gradient in risk did not vary substantially over time. The educational inequalities in cancer incidence observed in this cohort appear similar in magnitude and direction to socioeconomic inequalities found in other Western countries; for some cancer sites results partly differ from the results of other studies, and require further investigation. A thorough understanding of the relative burden of well-documented causes of social inequalities in cancer risk is essential to address preventive measures and to direct future research on unexplained social differences.
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Swaminathan R, Selvakumaran R, Vinodha J, Ferlay J, Sauvaget C, Esmy PO, Shanta V, Sankaranarayanan R. Education and cancer incidence in a rural population in south India. Cancer Epidemiol 2009; 33:89-93. [DOI: 10.1016/j.canep.2009.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 06/22/2009] [Accepted: 06/29/2009] [Indexed: 11/26/2022]
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Vidarsdottir H, Gunnarsdottir HK, Olafsdottir EJ, Olafsdottir GH, Pukkala E, Tryggvadottir L. Cancer risk by education in Iceland; a census-based cohort study. Acta Oncol 2009; 47:385-90. [PMID: 18348000 DOI: 10.1080/02841860801888773] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
UNLABELLED Earlier studies have shown that cancer risk is related to educational level in many countries. The relationship between education and cancer risk has not been studied in the small, but ethnically homogenous, Icelandic population postulated to be outstanding as regards social equity. MATERIAL AND METHODS We conducted a follow-up study of a cohort of 60,194 males and 58,505 females aged 20-64 at census 1981 in Iceland. Information on education from the census was classified into three educational groups and linked with the population-based Icelandic Cancer Registry. Standardized incidence ratios (SIRs) were calculated for the period 1982 to 2004. RESULTS We found a significant association between educational level and cancer risk. Among males with academic education, the SIR was elevated for prostate cancer (SIR=1.17, 95% CI 1.05-1.30) and melanoma (SIR=1.41, 95% CI 1.00-1.93) and lowered for cancers of the lung (SIR=0.72, 95% CI 0.59-0.87) and stomach (SIR=0.67, 95% CI 0.48-0.90). Women with academic education had an increased risk of breast cancer (SIR=1.19, 95% CI 1.07-1.33) and a decreased risk of lung cancer (SIR=0.49, 95% CI 0.36-0.65). Increasing educational level was associated with a lowered risk of cervical cancer (p trend=0.017). DISCUSSION The association between education and cancer incidence seen in this study resembles observations from other countries and probably reflects concordance between social status and certain risk factors for cancer. Our study confirms health-related socioeconomic differences in Iceland and must be taken into account when programmes for health promotion are planned.
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Weires M, Bermejo JL, Sundquist K, Sundquist J, Hemminki K. Socio-economic status and overall and cause-specific mortality in Sweden. BMC Public Health 2008; 8:340. [PMID: 18826562 PMCID: PMC2564940 DOI: 10.1186/1471-2458-8-340] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 09/30/2008] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Previous studies have reported discrepancies in cause-specific mortality among groups of individuals with different socio-economic status. However, most of the studies were limited by the specificity of the investigated populations and the broad definitions of the causes of death. The aim of the present population-based study was to explore the dependence of disease specific mortalities on the socio-economic status in Sweden, a country with universal health care. Another aim was to investigate possible gender differences. METHODS Using the 2006 update of the Swedish Family-Cancer Database, we identified over 2 million individuals with socio-economic data recorded in the 1960 national census. The association between mortality and socio-economic status was investigated by Cox's proportional hazards models taking into account the age, time period and residential area in both men and women, and additionally parity and age at first birth in women. RESULTS We observed significant associations between socio-economic status and mortality due to cardiovascular diseases, respiratory diseases, to cancer and to endocrine, nutritional and metabolic diseases. The influence of socio-economic status on female breast cancer was markedly specific: women with a higher socio-economic status showed increased mortality due to breast cancer. CONCLUSION Even in Sweden, a country where health care is universally provided, higher socio-economic status is associated with decreased overall and cause-specific mortalities. Comparison of mortality among female and male socio-economic groups may provide valuable insights into the underlying causes of socio-economic inequalities in length of life.
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Affiliation(s)
- Marianne Weires
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Justo Lorenzo Bermejo
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Kristina Sundquist
- Karolinska Institute, Center for Family and Community Medicine, 141 83 Huddinge, Sweden
| | - Jan Sundquist
- Karolinska Institute, Center for Family and Community Medicine, 141 83 Huddinge, Sweden
| | - Kari Hemminki
- Division of Molecular Genetic Epidemiology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
- Karolinska Institute, Center for Family and Community Medicine, 141 83 Huddinge, Sweden
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Ito S, Takachi R, Inoue M, Kurahashi N, Iwasaki M, Sasazuki S, Iso H, Tsubono Y, Tsugane S. Education in relation to incidence of and mortality from cancer and cardiovascular disease in Japan. Eur J Public Health 2008; 18:466-72. [DOI: 10.1093/eurpub/ckn052] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Fujino Y, Mori M, Tamakoshi A, Sakauchi F, Suzuki S, Wakai K, Tokudome S, Yoshimura T. A prospective study of educational background and breast cancer among Japanese women. Cancer Causes Control 2008; 19:931-7. [PMID: 18389378 DOI: 10.1007/s10552-008-9154-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Accepted: 03/21/2008] [Indexed: 10/22/2022]
Abstract
OBJECTIVE This prospective cohort study examined the association between educational level and breast cancer incidence in Japan. METHOD A baseline survey was conducted between 1988 and 1990 among 110,792 residents of 45 areas, aged 40-79 years. Data were restricted to 24 areas where incidence registry data were available, and to subjects which provided information on educational level (32,646). The subjects were assigned to three groups according to their level of education (<16, 16-18, 18<). During 13 years of follow-up (328,931 person-year), 169 cases of breast cancer were newly diagnosed. RESULTS Women with a high level of education had an increased risk of breast cancer (HR = 1.93, 95 percent confidence interval (95% CI): 1.18, 3.16, in women with the highest educational level) compared with women with the lowest educational level. Adjustment for lifestyle and reproductive factors did not substantially change the results. In addition, when analyses were stratified by age subgroups, the educational difference in breast cancer incidence was more evident among the younger than the elder subgroup. CONCLUSION The present results suggested that cancer prevention strategies should recognize women with a higher educational level as a high risk group for breast cancer.
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Affiliation(s)
- Yoshihisa Fujino
- Department of Preventive Medicine and Community Health, University of Occupational and Environmental Health, 1-1, Iseigaoka, Yahatanishiku, Kitakyushu, Japan.
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Soerjomataram I, Pukkala E, Brenner H, Coebergh JWW. On the avoidability of breast cancer in industrialized societies: older mean age at first birth as an indicator of excess breast cancer risk. Breast Cancer Res Treat 2007; 111:297-302. [PMID: 17932743 PMCID: PMC2491409 DOI: 10.1007/s10549-007-9778-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2007] [Accepted: 09/25/2007] [Indexed: 11/25/2022]
Abstract
Background Breast cancer incidence continuous to increase. We examined at population level the association between the relative excess risk of breast cancer and previous age of mother at first birth. Method Incidence of breast cancer in 34 industrialized countries was obtained from the GLOBOCAN 2002 and SEER databases. Data on age of mother at first birth was collected through national statistics offices. National relative excess risk (RER) was calculated by subtracting the lowest age-specific incidence rate from the rate in each population, and dividing the difference by the latter. Results The national RER in 2002 correlated closely with a higher average age at first birth in 1972, 1982, 1992 and also 2002, Pearson correlation [r] being 0.83, 0.79, 0.72 and 0.61, respectively; P < 0.0001. RER of breast cancer in 2002 for those aged 15–44 years correlated closely with the mean age at first birth in 1982 and 1992 (r: 0.81 and 0.75; P < 0.0001), whereas RER for those aged 45–54 years correlated strongly with age at first birth in 1972 and 1982 (r: 0.81 and 0.76; P < 0.0001), and for those aged 55–64 years with age at first birth in 1972 (r: 0.77; P < 0.0001). Conclusions The rising age at first childbirth of mothers has been followed by marked increases in breast cancer incidence. Later age at first birth seems to characterize secular diffusion of ‘modern’ lifestyles with a potentially large impact on increased breast cancer risk, and hence should be accompanied by greater opportunities for prevention through modifiable risk factors.
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Affiliation(s)
- Isabelle Soerjomataram
- Department of Public Health, Erasmus MC, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands,
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30
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Reply: Selection of controls. Br J Cancer 2007. [PMCID: PMC2360418 DOI: 10.1038/sj.bjc.6603976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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31
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von Euler-Chelpin M, Lynge E. Selection of controls. Br J Cancer 2007; 97:1019; author reply 1020. [PMID: 17876333 PMCID: PMC2360399 DOI: 10.1038/sj.bjc.6603975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- M von Euler-Chelpin
- Institute of Public Health, University of Copenhagen, Blegdamsvej 3, Copenhagen N, DK 2200, Denmark
- E-mail:
| | - E Lynge
- Institute of Public Health, University of Copenhagen, Blegdamsvej 3, Copenhagen N, DK 2200, Denmark
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Strand BH, Kunst A, Huisman M, Menvielle G, Glickman M, Bopp M, Borell C, Borgan JK, Costa G, Deboosere P, Regidor E, Valkonen T, Mackenbach JP. The reversed social gradient: higher breast cancer mortality in the higher educated compared to lower educated. A comparison of 11 European populations during the 1990s. Eur J Cancer 2007; 43:1200-7. [PMID: 17331712 DOI: 10.1016/j.ejca.2007.01.021] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/12/2007] [Accepted: 01/19/2007] [Indexed: 11/26/2022]
Abstract
Higher socioeconomic position has been reported to be associated with increased risk of breast cancer mortality. Our aim was to see if this is consistently observed within 11 European populations in the 1990s. Longitudinal data on breast cancer mortality by educational level and marital status were obtained for Finland, Norway, Denmark, England and Wales, Belgium, France, Switzerland, Austria, Turin, Barcelona and Madrid. The relationship between breast cancer mortality and education was summarised by means of the relative index of inequality. A positive association was found in all populations, except for Finland, France and Barcelona. Overall, women with a higher educational level had approximately 15% greater risk of dying from breast cancer than those with lower education. This was observed both among never- and ever-married women. The greater risk of breast cancer mortality among women with a higher level of education was a persistent and generalised phenomenon in Europe in the 1990s.
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Affiliation(s)
- Bjørn Heine Strand
- Division of Epidemiology, Norwegian Institute of Public Health, Nydalen, Oslo, Norway.
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Dalton SO, Düring M, Ross L, Carlsen K, Mortensen PB, Lynch J, Johansen C. The relation between socioeconomic and demographic factors and tumour stage in women diagnosed with breast cancer in Denmark, 1983-1999. Br J Cancer 2006; 95:653-9. [PMID: 16909141 PMCID: PMC2360690 DOI: 10.1038/sj.bjc.6603294] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The authors investigated the association between socioeconomic position and stage of breast cancer at the time of diagnosis in a nationwide Danish study. All 28 765 women with a primary invasive breast cancer diagnosed between 1983 and 1999 were identified in a nationwide clinical database and information on socioeconomic variables was obtained from Statistics Denmark. The risk of being diagnosed with a high-risk breast cancer, that is size >20 mm, lymph-node positive, ductal histology/high histologic grade and hormone receptor negative, was analysed by multivariate logistic regression. The adjusted odds ratio (OR) for high-risk breast cancer was reduced with longer education with a 12% reduced risk (95% confidence interval (CI), 0.80,0.96) in women with higher education and increased with reduced disposable income (low income group: OR, 1.22; 95% CI, 1.10,1.34). There was an urban–rural gradient, with higher risk among rural women (OR 1.10; 95 % CI, 1.02, 1.18) and lower risk among women in the capital suburbs (OR, 0.85; 95% CI, 0.78, 0.93) and capital area (OR, 0.93; 95% CI, 0.84–1.02). These factors were significant only for postmenopausal women, although similar patterns were observed among the premenopausal women, suggesting a subgroup of aggressive premenopausal breast cancers less influenced by socioeconomic factors.
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Affiliation(s)
- S O Dalton
- Department for Psychosocial Cancer Research, Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK-2100, Denmark.
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Langagergaard V, Gislum M, Skriver MV, Nørgård B, Lash TL, Rothman KJ, Sørensen HT. Birth outcome in women with breast cancer. Br J Cancer 2006; 94:142-6. [PMID: 16306874 PMCID: PMC2361078 DOI: 10.1038/sj.bjc.6602878] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We investigated whether maternal breast cancer affects birth outcome in a nationwide cohort study of 695 births from 1973 to 2002 of women with breast cancer with respect to preterm birth, low birth weight at term, stillbirth and congenital abnormalities as well as mean birth weight, compared with the outcomes of 33 443 births from unaffected mothers. There was no excess risk of adverse birth outcome for the 216 newborns of women with breast cancer before pregnancy. Stratification by mother's treatment did not change the results. For 37 newborns of women diagnosed during pregnancy, the prevalence ratio (PR) of preterm birth was 8.1 (95% confidence interval (CI): 3.8–17). However, 10 of the 12 preterm deliveries among these women were elective early deliveries. Among 442 births of women diagnosed in the 2 years from time of delivery, the PR of preterm birth was 1.4 (95% CI: 1.0–2.0), and the PR of low birth weight at term for boys was 2.9 (95% CI: 1.3–6.3). Overall, our results are reassuring regarding the risks of adverse birth outcome for breast cancer patients.
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Affiliation(s)
- V Langagergaard
- Department of Clinical Epidemiology, Aarhus University Hospital, Ole Worms Allé 150, DK-8000, Aarhus C, Denmark.
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Menvielle G, Leclerc A, Chastang JF, Luce D. Social inequalities in breast cancer mortality among French women: disappearing educational disparities from 1968 to 1996. Br J Cancer 2006; 94:152-5. [PMID: 16404368 PMCID: PMC2253682 DOI: 10.1038/sj.bjc.6602907] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
We investigated the time trends in social inequalities in breast cancer mortality with an analysis by age at death and birth cohort using a representative 1% sample of the French population and four subcohorts (1968–1974, 1975–1981, 1982–1988 and 1990–1996). Causes of death were obtained by direct linkage with the French national death registry. Education was measured at the beginning of each period, and educational disparities in breast cancer mortality were studied among women aged 35–74 at the beginning of each period. In the 1970s, higher breast cancer mortality was found among higher educated women. This positive association progressively weakened and no association remained in the 1990s although it disappeared earlier among younger women. In an analysis by birth cohort, the same pattern was found among women born before 1925, whereas no association between education and mortality was observed among women born after 1925. Educational disparities in breast cancer mortality are currently changing and the previously observed positive gradient has disappeared. An important question is whether these relations are indirect, and due to changes in the prevalence of risk factors associated with education, but which we could not study.
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Affiliation(s)
- G Menvielle
- INSERM, U687, Saint-Maurice F-94415, France.
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36
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Strand BH, Tverdal A, Claussen B, Zahl PH. Is birth history the key to highly educated women's higher breast cancer mortality? A follow-up study of 500,000 women aged 35-54. Int J Cancer 2005; 117:1002-6. [PMID: 15986427 DOI: 10.1002/ijc.21239] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A positive relationship has been found between high levels of education and breast cancer mortality. The aim of our study is to determine if the educational gradient in breast cancer mortality persists after adjustment for reproductive history. Register data including the total adult population in Norway were used. A total of 512,353 Norwegian women 35-54 years of age at the Norwegian Census in 1990 were followed with respect to breast cancer deaths until December 31, 2001. The analysis included 2,052 breast cancer deaths in 5.6 million person years. Educational differences in breast cancer mortality were analysed using Cox regression. The age adjusted relative risk of dying from breast cancer for women with >12 years of education compared to women with <10 years was 1.25 (95% confidence limits [CI] = 1.10-1.41). Adjustment for age at first birth with nulliparous as reference category reduced this difference to 1.08 (95% CI = 0.95-1.23). For parous women, age at first birth explained all the educational difference in breast cancer mortality. Among nulliparous women there was a larger positive educational gradient in breast cancer mortality than among parous women (relative risk [RR] = 1.57, 95% CI = 1.15-2.13), indicating that there were differences in other confounders than birth history among the childless.
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Affiliation(s)
- Bjørn Heine Strand
- Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
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Braaten T, Weiderpass E, Kumle M, Lund E. Explaining the Socioeconomic Variation in Cancer Risk in the Norwegian Women and Cancer Study. Cancer Epidemiol Biomarkers Prev 2005; 14:2591-7. [PMID: 16284383 DOI: 10.1158/1055-9965.epi-05-0345] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Associations between level of education and cancer risk is well supported by scientific evidence, but previous studies could only partly adjust for relevant confounding factors. In this article, we examined how risk of cancer varies with level of education and identified factors that explain this variation using data from a prospective cohort study, including 93,638 Norwegian women who responded to an extensive questionnaire in 1991/1992 or 1996/1997. A total of 3,259 incident primary invasive cancer cases were diagnosed during follow-up, which ended in December 2001. We used Cox proportional hazards model to calculate relative risks (RR) with 95% confidence intervals (95% CI). Besides a similar overall risk of female cancers by level of education, we observed differing risks between educational groups for cancers of the lung, breast, cervix, kidney, and skin melanoma. Women with >16 years of education had an increased risk of breast cancer (RR, 1.46; 95% CI, 1.19-1.79) and a decreased risk of lung cancer (RR, 0.30; 95% CI, 0.13-0.70) and cervical cancer (RR, 0.38; 95% CI, 0.17-0.85) compared with the lowest educated women (7-9 years). The middle educated (13-16 years) had the lowest risk of kidney cancer (RR, 0.24; 95% CI, 0.08-0.71), whereas the risk of skin melanoma was highest among women with 10 to 12 years of education (RR, 1.53; 95% CI, 1.05-2.24) compared with the lowest educated women. After multivariate adjustment for potential confounders related to level of education, the variation in cancer risk according to educational levels declined into nonsignificance for all these sites.
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Affiliation(s)
- Tonje Braaten
- Institute of Community Medicine, University of Tromsø, N-9037 Tromsø, Norway.
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