Birth size and breast cancer risk: Re-analysis of individual participant data from 32 studies

dos Santos Silva, I, De Stavola, B, McCormack, V, Lahmann, Petra and Collaborative Group on Pre-Natal Risk Factors and Subsequent Risk of Breast Cancer (2008) Birth size and breast cancer risk: Re-analysis of individual participant data from 32 studies. PLoS Medicine, 5 9: 1372-1386. doi:10.1371/journal.pmed.0050193


Author dos Santos Silva, I
De Stavola, B
McCormack, V
Lahmann, Petra
Collaborative Group on Pre-Natal Risk Factors and Subsequent Risk of Breast Cancer
Title Birth size and breast cancer risk: Re-analysis of individual participant data from 32 studies
Journal name PLoS Medicine   Check publisher's open access policy
ISSN 1549-1277
Publication date 2008-09-30
Year available 2008
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1371/journal.pmed.0050193
Open Access Status DOI
Volume 5
Issue 9
Start page 1372
End page 1386
Total pages 15
Editor Virginia Barbour
Place of publication United States
Publisher Public Library of Science
Collection year 2009
Language eng
Subject 920102 Cancer and Related Disorders
111799 Public Health and Health Services not elsewhere classified
11 Medical and Health Sciences
Formatted abstract
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 We re-analysed individual participant data from published and unpublished studies to obtain more precise estimates of the magnitude and shape of the birth size-breast cancer association.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.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Faculty of Health and Behavioural Sciences -- Publications
2009 Higher Education Research Data Collection
Excellence in Research Australia (ERA) - Collection
 
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Created: Tue, 17 Mar 2009, 14:09:00 EST by Geraldine Fitzgerald on behalf of School of Public Health