Abstract
The impact of single exposures on asthma development is better understood than is the effect of multiple exposures.
Evaluate effect of combined early exposure to dog allergen (Can-f1) plus indoor nitrogen dioxide (NO2) or environmental tobacco smoke (ETS) on asthma and bronchial hyperreactivity (BHR) in a high-risk birth cohort; assess atopy's impact on these exposures' effects.
Peri-birth ETS exposure was measured using cord blood cotinine (CCot). During year 1, atopy, NO2, Can-f1, and urinary cotinine:Cr (UCot) were measured. At age seven, 380 children were assessed for asthma and BHR. Exposure effects were determined by stepwise multiple linear regression.
Co-exposure to elevated Can-f1 and NO2, or Can-f1 and ETS (CCot), increased risk for asthma, relative to having neither such exposure (OR =4.8 [1.1–21.5], 2.7 [1.1–7.1] respectively); similar risks resulted when substituting dog ownership for allergen. Atopy increased asthma and BHR risk associated with several exposures; notably, atopy with elevated UCot, relative to atopy without such exposure, increased risk of BHR (OR =3.1 [1.1–8.6]).
In a high-risk birth cohort, early co-exposure to dog allergen and NO2 or ETS increased risk for incident asthma; atopy increased risk of asthma and BHR associated with ETS.
- ERS