title: Effect of low birth weight on childhood asthma: a meta-analysis.
abstract: BACKGROUND
  Low birth weight is strongly correlated with an increased risk of adult diseases. Additionally, low birth weight might be a risk factor for asthma later in life.
  
  
  METHODS
  A systematic literature search of the PubMed database from 1966 to November 2013 was conducted. The criteria for inclusion of papers were as follows: case-control or cohort studies; the odds ratio (OR) or risk ratio (RR) estimates with the corresponding 95% confidence intervals (CIs) were presented, or there were sufficient data for calculation; and studies were published in English up to October 2013. Random-effect and fixed-effect meta-analyses, meta-regression, and cumulative meta-analysis were conducted.
  
  
  RESULTS
  Thirteen cohort studies and 1,105,703 subjects were included. The overall pooled RRs (95% CIs) of asthma risk for low birth weight were 1.162 (fixed-effects model, 95% CI, 1.128-1.197) and 1.152 (random-effects model, 95% CI, 1.082-1.222). In stratified analyses, the effect of low birth weight on childhood asthma was strong, particularly in studies conducted in Europe, those with a small sample size, and those published recently. A meta-regression analysis did not find significant determinants.
  
  
  CONCLUSIONS
  This meta-analysis shows that low birth weight significantly increases the risk of childhood asthma.
authors.forename: Xue-Feng
authors.initials: XF
authors.lastname: Xu
authors.forename: Ying-Jun
authors.initials: YJ
authors.lastname: Li
authors.forename: Yuan-Jian
authors.initials: YJ
authors.lastname: Sheng
authors.forename: Jin-Ling
authors.initials: JL
authors.lastname: Liu
authors.forename: Lan-Fang
authors.initials: LF
authors.lastname: Tang
authors.affiliation: Department of Pulmonology, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China. drchenzm@163.com.
authors.forename: Zhi-Min
authors.initials: ZM
authors.lastname: Chen
mesh_terms: D001249:Asthma / Q000503:physiopathology*; D001724:Birth Weight / Q000502:physiology*; D002648:Child; D006801:Humans; D007231:Infant, Newborn; D012307:Risk Factors