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

@article{citeulike:3373149, abstract = {BackgroundBirth 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 We re-analysed individual participant data from published and unpublished studies to obtain more precise estimates of the magnitude and shape of the birth size–breast cancer association.Methods and FindingsStudies were identified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.ConclusionsThis 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.}, author = {Silva, Isabel and Stavola, Bianca D. and Mccormack, Valerie}, citeulike-article-id = {3373149}, citeulike-linkout-0 = {http://dx.doi.org/10.1371/journal.pmed.0050193}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18828667}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18828667}, comment = {Interesting meta-analysis that shows that increased birth-size may be associated with an increased risk of breast cancer. Relevant questions: -- What controls birth-size in babies (Diseases: Diabetes) -- What are the other pre-natal factors that interact with increased birth-size? -- What is the physiological role of increased birth-size in cancer causation? -- Is adiponectin involved in this association in some way?}, day = {1}, doi = {10.1371/journal.pmed.0050193}, journal = {PLoS Medicine}, keywords = {association, birth-size, breast, cancer, risk}, month = {September}, number = {9}, pages = {e193+}, posted-at = {2008-10-04 10:18:31}, priority = {2}, title = {Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies}, url = {http://dx.doi.org/10.1371/journal.pmed.0050193}, volume = {5}, year = {2008} }

TY - JOUR ID - citeulike:3373149 L3 - citeulike-article-id:3373149 N2 - BackgroundBirth 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 FindingsStudies 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.ConclusionsThis 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. IS - 9 JF - PLoS Medicine TI - Birth Size and Breast Cancer Risk: Re-analysis of Individual Participant Data from 32 Studies VL - 5 SP - e193 KW - association KW - birth-size KW - breast KW - cancer KW - risk N1 - Interesting meta-analysis that shows that increased birth-size may be associated with an increased risk of breast cancer. Relevant questions: -- What controls birth-size in babies (Diseases: Diabetes) -- What are the other pre-natal factors that interact with increased birth-size? -- What is the physiological role of increased birth-size in cancer causation? -- Is adiponectin involved in this association in some way? AU - Silva, Isabel AU - Stavola, Bianca AU - Mccormack, Valerie PY - 2008/09/01/ UR - http://dx.doi.org/10.1371/journal.pmed.0050193 ER -