Variables explaining variation in the prevalence of wheeze, asthma, atopic sensitization and bronchial responsiveness

WheezeAsthmaBronchial responsivenessAtopic sensitization
Female sex(+)
(In childhood)
(in adulthood)
Allergic sensitization(+)(+)+
Current smoking(+)(+)+
(to mite)
(to grass and cat)
Indoor environment
 Gas cooking+
(in women*)
 Cat ownership+
(to cat in subjects without symptoms)
 Damp dwellings(+)(+)(+)
 Occupational exposure+++
Genetic disposition
 Parental asthma+(+)
 Parental atopy(+)
Childhood risk factors
 Number of siblings(−)(−)(−)
 Dog in childhood
 Cat in childhood
(to cat in subjects with atopic heredity)
 Severe respiratory infections before the age of 5 yrs(+)
  • *: Heterogeneity between the centres

  • +: positive association

  • −: negative association

  • parentheses indicate the association was shown in local analysis, as opposed to the whole data set