aAdjusted for child exposure to active smoking in same room and home gas appliance use.

bAdjusted for sex, height, season of test, research technician, child exposure to tobacco smoke and home gas appliance use.  

Compared to non-HDM allergic children with feather quilts, children with the combination of HDM allergy and non-feather bedding (predominantly synthetic) were substantially more likely to have severe wheeze and a reduction in lung function.