In Estevan, associations were found between asthma and prior exposure to ETS from the father (OR=1.67, 95% CI 1.07 to 2.60), the presence of home mould or dampness (OR=1.96, 95% CI 1.41 to 2.72), the presence of air conditioning (OR=0.57, 95% CI 0.41 to 0.80), and the presence of a fireplace (OR=0.69, 95% CI 0.48 to 0.99).
In addition to the variable indicating the two communities, other risk factors were included in a multivariate logistic regression (change in -2 log likelihood = 444.90, degrees of freedom = 18, P<0.001). The strongest risk factor for asthma was the reporting of a respiratory allergy (OR=8.85, 95% CI 6.79 to 11.54). A history of early respiratory illness (OR=2.81, 95% CI 1.96 to 4.03) and a family history of asthma (OR=2.37, 95% CI 1.67 to 3.36) were also associated with asthma — flovent inhaler.
A significant effect modification was present between town and some household characteristics (Figure 1). In Estevan, the presence of home mould or dampness was associated with an increased risk of asthma (OR=1.82, 95% CI 1.23 to 2.69) and an inverse association with the presence of an air conditioner (OR=0.56, 95% CI 0.37 to 0.85).
Figure 1) Adjusted ORs between asthma and home mould or dampness, home air conditioning and current exposure to environmental tobacco smoke (ETS) from the mother. ORs have been adjusted for town (Estevan or Swift Current, Saskatchewan), age, sex, respiratory allergy, early respiratory illness, family history of asthma, ETS exposure from the mother, ETS exposure from the father, urban residence, home mould or dampness, air conditioning, home type and interaction terms for town by home mould or dampness, town by air conditioning, town by ETS exposure from the mother and town by home type