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Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies

BACKGROUND: Birth size, perhaps a proxy for prenatal environment, might be a correlate of subsequent breast cancer risk, but findings from epidemiological studies have been inconsistent. We re-analysed individual participant data from published and unpublished studies to obtain more precise estimate...

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Autores principales: dos Santos Silva, Isabel, Stavola, Bianca De, McCormack, Valerie
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2553821/
https://www.ncbi.nlm.nih.gov/pubmed/18828667
http://dx.doi.org/10.1371/journal.pmed.0050193
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author dos Santos Silva, Isabel
Stavola, Bianca De
McCormack, Valerie
author_facet dos Santos Silva, Isabel
Stavola, Bianca De
McCormack, Valerie
author_sort dos Santos Silva, Isabel
collection PubMed
description BACKGROUND: Birth size, perhaps a proxy for prenatal environment, might be a correlate of subsequent breast cancer risk, but findings from epidemiological studies have been inconsistent. We re-analysed individual participant data from published and unpublished studies to obtain more precise estimates of the magnitude and shape of the birth size–breast cancer association. METHODS AND FINDINGS: Studies were identified through computer-assisted and manual searches, and personal communication with investigators. Individual participant data from 32 studies, comprising 22,058 breast cancer cases, were obtained. Random effect models were used, if appropriate, to combine study-specific estimates of effect. Birth weight was positively associated with breast cancer risk in studies based on birth records (pooled relative risk [RR] per one standard deviation [SD] [= 0.5 kg] increment in birth weight: 1.06; 95% confidence interval [CI] 1.02–1.09) and parental recall when the participants were children (1.02; 95% CI 0.99–1.05), but not in those based on adult self-reports, or maternal recall during the woman's adulthood (0.98; 95% CI 0.95–1.01) (p for heterogeneity between data sources = 0.003). Relative to women who weighed 3.000–3.499 kg, the risk was 0.96 (CI 0.80–1.16) in those who weighed < 2.500 kg, and 1.12 (95% CI 1.00–1.25) in those who weighed ≥ 4.000 kg (p for linear trend = 0.001) in birth record data. Birth length and head circumference from birth records were also positively associated with breast cancer risk (pooled RR per one SD increment: 1.06 [95% CI 1.03–1.10] and 1.09 [95% CI 1.03–1.15], respectively). Simultaneous adjustment for these three birth size variables showed that length was the strongest independent predictor of risk. The birth size effects did not appear to be confounded or mediated by established breast cancer risk factors and were not modified by age or menopausal status. The cumulative incidence of breast cancer per 100 women by age 80 y in the study populations was estimated to be 10.0, 10.0, 10.4, and 11.5 in those who were, respectively, in the bottom, second, third, and top fourths of the birth length distribution. CONCLUSIONS: This pooled analysis of individual participant data is consistent with birth size, and in particular birth length, being an independent correlate of breast cancer risk in adulthood.
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spelling pubmed-25538212008-09-27 Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies dos Santos Silva, Isabel Stavola, Bianca De McCormack, Valerie PLoS Med Research Article BACKGROUND: Birth size, perhaps a proxy for prenatal environment, might be a correlate of subsequent breast cancer risk, but findings from epidemiological studies have been inconsistent. We re-analysed individual participant data from published and unpublished studies to obtain more precise estimates of the magnitude and shape of the birth size–breast cancer association. METHODS AND FINDINGS: Studies were identified through computer-assisted and manual searches, and personal communication with investigators. Individual participant data from 32 studies, comprising 22,058 breast cancer cases, were obtained. Random effect models were used, if appropriate, to combine study-specific estimates of effect. Birth weight was positively associated with breast cancer risk in studies based on birth records (pooled relative risk [RR] per one standard deviation [SD] [= 0.5 kg] increment in birth weight: 1.06; 95% confidence interval [CI] 1.02–1.09) and parental recall when the participants were children (1.02; 95% CI 0.99–1.05), but not in those based on adult self-reports, or maternal recall during the woman's adulthood (0.98; 95% CI 0.95–1.01) (p for heterogeneity between data sources = 0.003). Relative to women who weighed 3.000–3.499 kg, the risk was 0.96 (CI 0.80–1.16) in those who weighed < 2.500 kg, and 1.12 (95% CI 1.00–1.25) in those who weighed ≥ 4.000 kg (p for linear trend = 0.001) in birth record data. Birth length and head circumference from birth records were also positively associated with breast cancer risk (pooled RR per one SD increment: 1.06 [95% CI 1.03–1.10] and 1.09 [95% CI 1.03–1.15], respectively). Simultaneous adjustment for these three birth size variables showed that length was the strongest independent predictor of risk. The birth size effects did not appear to be confounded or mediated by established breast cancer risk factors and were not modified by age or menopausal status. The cumulative incidence of breast cancer per 100 women by age 80 y in the study populations was estimated to be 10.0, 10.0, 10.4, and 11.5 in those who were, respectively, in the bottom, second, third, and top fourths of the birth length distribution. CONCLUSIONS: This pooled analysis of individual participant data is consistent with birth size, and in particular birth length, being an independent correlate of breast cancer risk in adulthood. Public Library of Science 2008-09 2008-09-30 /pmc/articles/PMC2553821/ /pubmed/18828667 http://dx.doi.org/10.1371/journal.pmed.0050193 Text en Copyright: © 2008 dos Santos Silva et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
dos Santos Silva, Isabel
Stavola, Bianca De
McCormack, Valerie
Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title_full Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title_fullStr Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title_full_unstemmed Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title_short Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies
title_sort birth size and breast cancer risk: re-analysis of individual participant data from 32 studies
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2553821/
https://www.ncbi.nlm.nih.gov/pubmed/18828667
http://dx.doi.org/10.1371/journal.pmed.0050193
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