title: The influence of parents, older siblings, and non-parental care on infant development at nine months of age.
abstract: BACKGROUND
  The majority of research examining the influence of social environment on early child development suggests benefits to two-parent households, but contradictory evidence for the effects of siblings. The aims of the present study were to examine the influence of the child's proximal social environment, and the effects of interactions between socioeconomic status and social environment on developmental outcomes.
  
  
  METHODS
  Primary caregivers of a representative sample of 10,748 nine-month-old infants in Ireland completed the Ages and Stages Questionnaire and provided information on social environment. Adjustment was made for infant and maternal characteristics, household income, and area where the child was living at the time of the study. Further analyses tested for interactions between social environment and household income.
  
  
  RESULTS
  Binary logistic regressions indicated no effects for number of parents in the household. However, the presence of siblings in the household was a consistent predictor of failing to reach milestones in communication, gross motor, problem-solving, and personal-social development. Furthermore, there was a gradient of increasing likelihood of failing in gross motor, problem-solving, and personal-social development with increasing numbers of siblings. Care by a grandparent decreased the likelihood of failing in communication and personal-social development.
  
  
  CONCLUSIONS
  These findings do not support the majority of research that finds positive benefits for two-parent households. Similarly, the findings suggest limited effects for non-parental care. However, the observed negative effects of siblings support both the confluence and resource dilution models of sibling effect. Examination of follow-up data may elucidate current findings.
authors: Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom. Electronic address: s.cruise@qub.ac.uk.
authors: Sharon
authors: S
authors: Cruise
authors: Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom; UKCRC Centre of Excellence for Public Health (NI), Centre for Public Health, Queen's University Belfast, Belfast, Northern Ireland, United Kingdom.
authors: Dermot
authors: D
authors: O'Reilly
mesh_terms: D000328:Adult; D017028:Caregivers; D002657:Child Development / Q000502:physiology*; D004522:Educational Status; D005260:Female; D006801:Humans; D007182:Income; D007223:Infant; D007224:Infant Care / Q000523:psychology*; D007494:Ireland; D008297:Male; D010290:Parents; D035781:Siblings; D020954:Single-Parent Family / Q000523:psychology; D012931:Social Environment; D012959:Socioeconomic Factors
keywords: Infant development; Non-parental care; Parents; Siblings