title: Family size, infections, and asthma prevalence in New Zealand children.
abstract: We conducted a prevalence case-control study to investigate the relation between family composition, infection, and development of asthma at age 7-9 years. Potential cases (399) and controls (398) were selected from the Wellington, NZ, arm of the International Study of Asthma and Allergies in Childhood, a population-based prevalence study. Further screening questions restricted cases to children with a diagnosis of asthma and current medication use (N = 233) and restricted controls to children without a history of wheezing and no diagnosis of asthma (N = 241). After controlling for confounders (including infections, atopy, and socioeconomic status), family size was strongly related to asthma. Having no siblings [prevalence odds ratio (POR) = 2.51; 95% confidence interval (CI) = 1.05-6.01] or one sibling (POR = 1.86; 95% CI = 1.14-3.03) was associated with an increased risk of asthma compared with having more than one sibling. Parent-reported rubeola infection (and possibly other similar viral exanthems) was independently associated with a decreased risk of asthma (POR = 0.48; 95% CI = 0.27-0.83), but reported pertussis infection (POR = 1.57; 95% CI = 0.58-4.24) and day care attendance in the first year of life (POR = 1.81; 95% CI = 0.93-3.51) were not strongly associated with increased risks of asthma.
authors.affiliation: Wellington Asthma Research Group, Wellington School of Medicine, Wellington South, New Zealand.
authors.forename: K L
authors.initials: KL
authors.lastname: Wickens
authors.forename: J
authors.initials: J
authors.lastname: Crane
authors.forename: T J
authors.initials: TJ
authors.lastname: Kemp
authors.forename: S J
authors.initials: SJ
authors.lastname: Lewis
authors.forename: W J
authors.initials: WJ
authors.lastname: D'Souza
authors.forename: G M
authors.initials: GM
authors.lastname: Sawyer
authors.forename: M L
authors.initials: ML
authors.lastname: Stone
authors.forename: S J
authors.initials: SJ
authors.lastname: Tohill
authors.forename: J C
authors.initials: JC
authors.lastname: Kennedy
authors.forename: T M
authors.initials: TM
authors.lastname: Slater
authors.forename: N E
authors.initials: NE
authors.lastname: Pearce
mesh_terms: D001249:Asthma / Q000453:epidemiology*; D016022:Case-Control Studies; D002648:Child; D003141:Communicable Diseases / Q000453:epidemiology*; D005191:Family Characteristics; D006801:Humans; D009520:New Zealand / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D012882:Skin Tests; D012959:Socioeconomic Factors