Socioeconomic and sociodemographic factors associated with wheezing and asthma at age 6 years.

Socioeconomic and sociodemographic factors were imputed by multiple imputation. Abbreviations: OR = odds ratio, CI = confidence interval. Odds ratios (95% confidence intervals) from logistic regression models. All bold values are significant (p-values <0.05).
+Model 1 is adjusted for potential confounders including maternal age at enrollment, child's sex, ethnicity and age at outcome measurement.
±Model 2 is adjusted for potential confounders and other socioeconomic and sociodemographic factors.
†Model 3 was adjusted for potential confounders, other socioeconomic and sociodemographic factors and potential mediating factors. Mediating factors include maternal smoking during pregnancy, maternal psychopathology, maternal BMI, maternal history of asthma or atopy, gestational age at birth, birth weight, having breastfeeding ever, tobacco smoke exposure at home, pet exposure at home, daycare attendance, eczema ever and respiratory tract infections.
aDefined as an education less than the level of a bachelor's/master's degree (HBO/University in Dutch system) for 1 parent (in the case that educational level was known for one parent) or for 2 parents (in the case that educational level was known for both parents). Data on parental education was obtained by questionnaire.
bData on net household income (<€2000/month, ≥€2000/month) was obtained by questionnaire at the child's age of 2 or 3 years, using the 2012 monthly general labour income as the cut-off point [30].
cDefined as difficulties in paying food, rent, electricity bill and suchlike, assessed by questionnaire during pregnancy.
dPaternal and maternal unemployment were defined as no paid job, assessed by questionnaires at child's age of 6 years.
eDefined as a pregnancy in girls aged 19 or younger.
fChild's ethnicity was defined according to the classification of Statistics Netherlands [31].