title: Is birthweight associated with total and aggressive/lethal prostate cancer risks? A systematic review and meta-analysis.
abstract: BACKGROUND
  It has been hypothesised that intrauterine exposures are important for subsequent prostate cancer risk. Prior epidemiological studies have used birthweight as a proxy of cumulative intrauterine exposures to test this hypothesis, but results have been inconsistent partly because of limited statistical power.
  
  
  METHODS
  We investigated birthweight in relation to prostate cancer in the Medical Research Council (MRC) National Survey of Health and Development (NSHD) using Cox proportional hazards models. We then conducted a meta-analysis of birthweight in relation to total and aggressive/lethal prostate cancer risks, combining results from the NSHD analysis with 13 additional studies on this relationship identified from a systematic search in four major scientific literature databases through January 2015.
  
  
  RESULTS
  Random-effects models found that per kg increase in birthweight was positively associated with total (OR=1.02, 95% confidence interval (95% CI)=1.00, 1.05; I(2)=13%) and aggressive/lethal prostate cancer (OR=1.08, 95% CI=0.99, 1.19; I(2)=40%). Sensitivity analyses restricted to studies with birthweight extracted from medical records demonstrated stronger positive associations with total (OR=1.11, 95% CI=1.03, 1.19; I(2)=0%) and aggressive/lethal (OR=1.37, 95% CI=1.09, 1.74; I(2)=0%) prostate cancer. These studies heavily overlapped with those based in Nordic countries.
  
  
  CONCLUSIONS
  This study provides evidence that heavier birthweight may be associated with modest increased risks of total and aggressive/lethal prostate cancer, which supports the hypothesis that intrauterine exposures may be related to subsequent prostate cancer risks.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, NIH, DHHS, 9609 Medical Center Drive, MSC 9774, Bethesda, MD 20892-9774, USA.
authors.forename: Cindy Ke
authors.initials: CK
authors.lastname: Zhou
authors.affiliation: Division of Public Health Sciences and the Siteman Cancer Center, Department of Surgery, Washington University School of Medicine, St Louis, MO, USA.
authors.forename: Siobhan
authors.initials: S
authors.lastname: Sutcliffe
authors.affiliation: NIH Library, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Judith
authors.initials: J
authors.lastname: Welsh
authors.affiliation: Medical Research Council Unit for Lifelong Health and Ageing, University College London, London, UK.
authors.forename: Karen
authors.initials: K
authors.lastname: Mackinnon
authors.affiliation: Medical Research Council Unit for Lifelong Health and Ageing, University College London, London, UK.
authors.forename: Diana
authors.initials: D
authors.lastname: Kuh
authors.affiliation: Medical Research Council Unit for Lifelong Health and Ageing, University College London, London, UK.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hardy
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, NIH, DHHS, 9609 Medical Center Drive, MSC 9774, Bethesda, MD 20892-9774, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Cook
mesh_terms: D001724:Birth Weight; D016022:Case-Control Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000209:etiology* / Q000473:pathology*; D018570:Risk Assessment