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Sex differences in long-term outcomes after Group B streptococcal infections during infancy in Denmark and the Netherlands: national cohort studies of neurodevelopmental impairments and mortality

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  • Merel N van Kassel, University of Amsterdam
  • ,
  • Bronner P Gonçalves, London School of Hygiene and Tropical Medicine
  • ,
  • Linde L Snoek, University of Amsterdam
  • ,
  • Henrik T Sørensen
  • Merijn W Bijlsma, University of Amsterdam
  • ,
  • Joy E Lawn, London School of Hygiene and Tropical Medicine
  • ,
  • Erzsébet Horváth-Puhó
  • GBS Danish and Dutch collaborative group for long term outcomes

BACKGROUND: Male infants have a higher incidence of invasive group B Streptococcus disease (iGBS) compared with female infants; however, data on sex differences in mortality and long-term outcomes after iGBS are lacking. We assessed whether a child's sex influences the effects of iGBS on mortality and risk of neurodevelopmental impairments (NDIs).

METHODS: We used Danish and Dutch registry data to conduct a nationwide cohort study of infants with a history of iGBS. A comparison cohort, children without a history of iGBS, was randomly selected and matched on relevant factors. Effect modification by sex was assessed on additive and multiplicative scales.

RESULTS: Our analyses included data from children with a history of iGBS in Denmark (period 1997 -2017; n = 1432) and the Netherlands (2000 -2017; n = 697) and from 21 172 children without iGBS. There was no clear evidence of between-sex heterogeneity in iGBS-associated mortality. Boys had a higher risk of NDI, with evidence for effect modification on additive scale at the age of 5 years for any NDI (relative excess risk due to interaction = 1.28; 95% confidence interval [CI], -0.53 to 3.09 in Denmark and 1.14; 95% CI, -5.13 to 7.41 in the Netherlands). A similar pattern was observed for moderate/severe NDI at age 5 years in Denmark and age 10 years in the Netherlands.

CONCLUSION: Boys are at higher risk of NDI ; our results suggest this is disproportionally increased in those who develop iGBS. Future studies should investigate mechanisms of this effect modification by sex.

Original languageEnglish
JournalClinical infectious diseases : an official publication of the Infectious Diseases Society of America
IssueSupplement 1
Pages (from-to) S54–S63
Number of pages10
Publication statusPublished - Jan 2022

    Research areas

  • group B Streptococcus, effect modification, neurodevelopmental impairments, Streptococcus agalactiae, sex differences, Humans, Risk Factors, Child, Preschool, Infant, Male, Streptococcal Infections/epidemiology, Sex Characteristics, Denmark/epidemiology, Infant, Premature, Female, Netherlands/epidemiology, Child, Infant, Newborn, Cohort Studies

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