Prenatal and lifetime exposure to pets and development of allergic rhinitis in the first 12 years of life

<bold>Background:</bold> We assessed potential relations between pet keeping and development of allergic rhinitis up to 12 years of age. <bold>Methods:</bold> We conducted a population-based cohort study of 2,568 newborns from the Espoo Cohort Study, who were born between 1984 and 1990, and living in the City of Espoo, Finland. We assessed parental reports of having cats and/or dogs during pregnancy, and at 0-1, 1-3, 4-6, 7-9 and 10-12 years of life and the onset of allergic rhinitis (AR) during the first 12 years of life. We estimated adjusted risk ratios (aRR) with their 95% confidence intervals (CI) applying Poisson regression to adjust for potential confounding. <bold>Results:</bold> Cat keeping reduced 61% the risk of AR (aRR 0.39, 0.25,0.63) and dog keeping 69% (aRR 0.31, 0.20,0.49), both showing a dose-response pattern with duration. Keeping both cats and dogs were related to 90% risk reduction (aRR 0.10, (0.03,0.42). <bold>Conclusions:</bold> The risk of allergic rhinitis is related to both the presence of exposure to dogs and/or cats any time any time and duration of such exposures. <bold>Table 1.</bold> Risk of allergic rhinitis related to periods of cat and dog keeping since the birth. <table-wrap><object-id>erj;64/suppl_68/PA1316/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col><col></col><col></col><col></col><col></col><col></col></colgroup><tbody><tr><td></td><td><bold>Any time</bold></td><td><bold>1 time period</bold></td><td><bold>2 time periods</bold></td><td><bold>3 time periods</bold></td><td><bold>All time periods</bold></td><td><bold>MH-test</bold></td></tr><tr><td><bold>Pet keeping</bold></td><td>aRR¹ (95% CI)</td><td>aRR¹ (95% CI)</td><td>aRR¹ (95% CI)</td><td>aRR¹ (95% CI)</td><td>aRR¹ (95% CI)</td><td><italic>p</italic> for trend</td></tr><tr><td><bold>None</bold></td><td>1.00</td><td>1.00</td><td>1.00</td><td>1.00</td><td>1.00</td><td>NA</td></tr><tr><td><bold>Cat(s) only</bold></td><td>0.39 (0.25, 0.63)</td><td>0.69 (0.34, 1.41)</td><td>0.46 (0.17, 1.24)</td><td>0.44 (0.21, 0.95)</td><td>0.34 (0.05, 2.24)</td><td>0.0012</td></tr><tr><td><bold>Dog(s) only</bold></td><td>0.31 (0.20, 0.49)</td><td>0.20 (0.07, 0.55)</td><td>0.59 (0.28, 1.26)</td><td>0.37 (0.20, 0.70)</td><td>0.26 (0.04, 1.88)</td><td><0.0001</td></tr><tr><td><bold>Cat(s) and dog(s)</bold></td><td>0.10 (0.03, 0.42)</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td><td>NA</td></tr></tbody></table></table-wrap> ¹Adjusted for sex, age, SES, maternal smk in pregnancy, ETS, and parental atopy.