title: Effect of Consanguinity on Low Birth Weight: A Meta-Analysis.
abstract: BACKGROUND
  Consanguinity (when couples share at least one common ancestor) is a public health issue with a variety of distributions and incidence rates worldwide. Several epidemiological studies have explored the association between consanguinity and low birth weight (LBW). However, the results are inconsistent. This meta-analysis aimed to explore the overall association between consanguineous marriage and LBW.
  
  
  METHODS
  We searched PubMed, Web of Science, Scopus, ScienceDirect, and reference lists of articles up to May 2015. We included cohort, case-control, and cross-sectional studies addressing the association between consanguinity and LBW. We assessed heterogeneity using Q-test and I2 statistic. We explored publication bias using the Egger's and Begg's tests and the funnel plot. We meta-analyzed the data and reported the overall odds ratio (OR) and mean difference with 95% confidence intervals (CI) using the random-effects model.
  
  
  RESULTS
  We included 24 out of 3941 retrieved studies, with 44,131 participants. We indicated that LBW was associated significantly with first-cousin marriages (OR = 1.36; 95% CI: 1.03, 1.69) and non-significantly with second-cousin marriages (OR = 1.20; 95% CI: 0.49, 1.91). Furthermore, first-cousin marriages can reduce the birth weight of siblings of consanguineous couples 144 g more compared to non-consanguineous marriages.
  
  
  CONCLUSIONS
  This meta-analysis measured the association between consanguinity and LBW. Based on the current evidence, consanguineous marriage can increase the risk for LBW. However, further evidence based on large cohort studies conducted in different settings is required to make a robust conclusion regarding the effect of consanguinity on LBW.
authors.affiliation: Modeling of Non-communicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran, Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Jalal
authors.initials: J
authors.lastname: Poorolajal
authors.affiliation: Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Pegah
authors.initials: P
authors.lastname: Ameri
authors.affiliation: Modeling of Non-communicable Diseases Research Center, Hamadan University of Medical Sciences, Hamadan, Iran, Department of Biostatistics, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Soltanian
authors.affiliation: Department of Epidemiology, School of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Bahrami
mesh_terms: D003241:Consanguinity; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D016017:Odds Ratio; D012307:Risk Factors