Exposure to Cats and Dogs, and Symptoms of Asthma, Rhinoconjunctivitis, and Eczema
Journal
Epidemiology
Date Issued
2012-09
Author(s)
Brunekreef, Bert
Von Mutius, Erika
Wong, Gary
Odhiambo, Joseph
García-Marcos, Luis
Foliaki, Sunia
The ISAAC Phase Three Study Group
DOI
10.1097/ede.0b013e318261f040
Abstract
Background: Associations between exposure to cats and dogs and
respiratory and allergic outcomes in children have been reported in
affluent countries, but little is known about such associations in
less-affluent countries.
Methods: The International Study of Asthma and Allergies in
Childhood, phase 3 was carried out in children aged 6–7 years and
adolescents aged 13–14 years across the world. Questions about cats
and dogs in the home were included in an additional questionnaire.
Using logistic regression, we investigated the association between
such exposures and symptoms of asthma, rhinoconjunctivitis, and
eczema. Adjustments were made for sex, region of the world,
language, gross national income per capita, and 10 other covariates.
Results: Among children (6–7 years of age), cat exposure in the first
year of life was associated with current symptoms of asthma,
wheeze, rhinoconjunctivitis, and eczema, especially in less-affluent
countries. Among adolescents (13–14 years of age), we found a
positive association between exposure to cats or dogs and symptom
prevalence in more-affluent and less-affluent countries. The global
multivariate odds ratios for children with complete covariate data
were 1.17 (95% confidence interval = 1.08 –1.29) for current symptoms
of asthma, 1.13 (1.05–1.23) for rhinoconjunctivitis, and 1.38
(1.26 –1.52) for eczema. Smaller odds ratios were found for exposure
to only dogs. Exposure to only cats was associated with eczema.
Conclusion: Early-life exposure to cats is a risk factor for symptoms
of asthma, rhinoconjunctivitis, and eczema in 6- to 7-year-old
children, especially in less-affluent countries. Current exposure to cats and dogs combined, and only to dogs, is a risk factor for symptom reporting by 13- to 14-year-old adolescents worldwide.
respiratory and allergic outcomes in children have been reported in
affluent countries, but little is known about such associations in
less-affluent countries.
Methods: The International Study of Asthma and Allergies in
Childhood, phase 3 was carried out in children aged 6–7 years and
adolescents aged 13–14 years across the world. Questions about cats
and dogs in the home were included in an additional questionnaire.
Using logistic regression, we investigated the association between
such exposures and symptoms of asthma, rhinoconjunctivitis, and
eczema. Adjustments were made for sex, region of the world,
language, gross national income per capita, and 10 other covariates.
Results: Among children (6–7 years of age), cat exposure in the first
year of life was associated with current symptoms of asthma,
wheeze, rhinoconjunctivitis, and eczema, especially in less-affluent
countries. Among adolescents (13–14 years of age), we found a
positive association between exposure to cats or dogs and symptom
prevalence in more-affluent and less-affluent countries. The global
multivariate odds ratios for children with complete covariate data
were 1.17 (95% confidence interval = 1.08 –1.29) for current symptoms
of asthma, 1.13 (1.05–1.23) for rhinoconjunctivitis, and 1.38
(1.26 –1.52) for eczema. Smaller odds ratios were found for exposure
to only dogs. Exposure to only cats was associated with eczema.
Conclusion: Early-life exposure to cats is a risk factor for symptoms
of asthma, rhinoconjunctivitis, and eczema in 6- to 7-year-old
children, especially in less-affluent countries. Current exposure to cats and dogs combined, and only to dogs, is a risk factor for symptom reporting by 13- to 14-year-old adolescents worldwide.