title: The large contribution of twins to neonatal and post-neonatal mortality in The Gambia, a 5-year prospective study.
abstract: BACKGROUND
  A high twinning rate and an increased risk of mortality among twins contribute to the high burden of infant mortality in Africa. This study examined the contribution of twins to neonatal and post-neonatal mortality in The Gambia, and evaluated factors that contribute to the excess mortality among twins.
  
  
  METHODS
  We analysed data from the Basse Health and Demographic Surveillance System (BHDSS) collected from January 2009 to December 2013. Demographic and epidemiological variables were assessed for their association with mortality in different age groups.
  
  
  RESULTS
  We included 32,436 singletons and 1083 twins in the analysis (twining rate 16.7/1000 deliveries). Twins represented 11.8 % of all neonatal deaths and 7.8 % of post-neonatal deaths. Mortality among twins was higher than in singletons [adjusted odds ratio (AOR) 4.33 (95 % CI: 3.09, 6.06) in the neonatal period and 2.61 (95 % CI: 1.85, 3.68) in the post-neonatal period]. Post-neonatal mortality among twins increased in girls (P for interaction = 0.064), being born during the dry season (P for interaction = 0.030) and lacking access to clean water (P for interaction = 0.042).
  
  
  CONCLUSIONS
  Mortality among twins makes a significant contribution to the high burden of neonatal and post-neonatal mortality in The Gambia and preventive interventions targeting twins should be prioritized.
authors.affiliation: Medical Research Council, Banjul, The Gambia.|Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan.
authors.forename: Reiko
authors.initials: R
authors.lastname: Miyahara
authors.affiliation: Medical Research Council, Banjul, The Gambia.
authors.forename: Momodou
authors.initials: M
authors.lastname: Jasseh
authors.affiliation: Medical Research Council, Banjul, The Gambia.|MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK.|Murdoch Children Research Institute, Melbourne, Australia.
authors.forename: Grant Austin
authors.initials: GA
authors.lastname: Mackenzie
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Christian
authors.initials: C
authors.lastname: Bottomley
authors.affiliation: Medical Research Council, Banjul, The Gambia.
authors.forename: M Jahangir
authors.initials: MJ
authors.lastname: Hossain
authors.affiliation: Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Greenwood
authors.affiliation: Medical Research Council, Banjul, The Gambia.|Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: Umberto
authors.initials: U
authors.lastname: D'Alessandro
authors.affiliation: Medical Research Council, Banjul, The Gambia. aroca@mrc.gm.|Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK. aroca@mrc.gm.
authors.forename: Anna
authors.initials: A
authors.lastname: Roca
mesh_terms: D005260:Female; D005714:Gambia / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D014427:Twins / Q000706:statistics & numerical data*
keywords: HDSS; Mortality; Neonatal; Post-neonatal; Risk factors; Twins