title: Crowding and other strong predictors of upper respiratory tract carriage of otitis media-related bacteria in Australian Aboriginal and non-Aboriginal children.
abstract: BACKGROUND
  Streptococcus pneumoniae, Moraxella catarrhalis, and nontypeable Haemophilus influenzae is associated with otitis media (OM). Data are limited on risk factors for carriage of these pathogens, particularly for Indigenous populations. We investigated predictors of nasopharyngeal carriage in Australian Aboriginal and non-Aboriginal children.
  
  
  METHODS
  Nasopharyngeal aspirates were collected up to 7 times before age 2 years from 100 Aboriginal and 180 non-Aboriginal children. Longitudinal modeling estimated effects of environmental factors and concurrent carriage of other bacteria on the probability of bacterial carriage. We present a novel method combining the effects of number of household members and size of house into an overall crowding model.
  
  
  RESULTS
  Each additional household member increased the risk of carriage of S. pneumoniae (odds ratio [OR] = 1.45 per additional Aboriginal child in a 4-room house, 95% confidence interval [CI]: 1.15-1.84; OR = 2.34 per additional non-Aboriginal child, 95% CI: 1.76-3.10), with similar effect sizes for M. catarrhalis, and nontypeable Haemophilus influenzae. However, living in a larger house attenuated this effect among Aboriginal children. Daycare attendance predicted carriage of the 3 OM-associated bacteria among non-Aboriginal children. Exclusive breast-feeding at 6 to 8 weeks protected against Streptococcus aureus carriage (OR = 0.42, 95% CI: 0.19-0.90 in Aboriginal children and OR = 0.49, 95% CI: 0.25-0.96 in non-Aboriginal children). OM-associated bacteria were more likely to be present if there was concurrent carriage of the other OM-associated species.
  
  
  CONCLUSIONS
  This study highlights the importance of household transmission in carriage of OM bacteria, underscoring the need to reduce the crowding in Aboriginal households.
authors: Centre for Child Health Research, Telethon Institute for Child Health Research, The University of Western Australia, Perth, Australia. peterj@ichr.uwa.edu.au
authors: Peter
authors: P
authors: Jacoby
authors: Kylie S
authors: KS
authors: Carville
authors: Gillian
authors: G
authors: Hall
authors: Thomas V
authors: TV
authors: Riley
authors: Jacinta
authors: J
authors: Bowman
authors: Amanda J
authors: AJ
authors: Leach
authors: Deborah
authors: D
authors: Lehmann