Dog Ownership Enhances Symptomatic Responses to Air Pollution in Children with Asthma

Abstract

BackgroundExperimental data suggest that asthma exacerbation by ambient air pollutants is enhanced by exposure to endotoxin and allergens; however, there is little supporting epidemiologic evidence.MethodsWe evaluated whether the association of exposure to air pollution with annual prevalence of chronic cough, phlegm production, or bronchitis was modified by dog and cat ownership (indicators of allergen and endotoxin exposure). The study population consisted of 475 Southern California children with asthma from a longitudinal cohort of participants in the Children’s Health Study. We estimated average annual ambient exposure to nitrogen dioxide, ozone, particulate matter < 10, 2.5, and 10–2.5 μm in aerodynamic diameter (PM10, PM2.5, and PM10–2.5, respectively), elemental and organic carbon, and acid vapor from monitoring stations in each of the 12 study communities. Multivariate models were used to examine the effect of yearly variation of each pollutant. Effects were scaled to the variability that is common for each pollutant in representative communities in Southern California.ResultsAmong children owning a dog, there were strong associations between bronchitic symptoms and all pollutants examined. Odds ratios ranged from 1.30 per 4.2 μg/m3 for PM10–2.5 [95% confidence interval (CI), 0.91–1.87) to 1.91 per 1.2 μg/m3 for organic carbon (95% CI, 1.34–2.71). Effects were somewhat larger among children who owned both a cat and dog. There were no effects or small effects with wide CIs among children without a dog and among children who owned only a cat.ConclusionOur results suggest that dog ownership, a source of residential exposure to endotoxin, may worsen the relationship between air pollution and respiratory symptoms in asthmatic children.

Exposure to Traffic-related Particles and Endotoxin during Infancy Is Associated with Wheezing at Age 3 Years

“…In school-age children with asthma, McConnell and colleagues (48) reported that among children who owned a dog (a potential surrogate of endotoxin exposure) the odds ratio for increased bronchitis symptoms per 4.2 ppb increase in NO 2 exposure was 1.49 (95% CI, 1.14-1.95) compared with an odds ratio of 1.16 (95% CI, 0.84-1.60) among children with no dog in the home. In the current study, the prevalence of persistent wheeze among children exposed to high levels of ECAT but low levels of endotoxin was 18%.…”

Parental Stress Increases the Detrimental Effect of Traffic Exposure on Children's Lung Function

“…Exposure to air pollution, especially to local particulate and the traffic-related air pollution (TRP) mixture near children's homes, has been associated with asthma prevalence, incidence, and exacerbation, and with lung function deficits (1)(2)(3)(4)(5)(6)(7)(8). Genetic and toxicologic studies suggest that these relationships are causal (9)(10)(11)(12).…”

Can dog allergen alone, if combined with indoor pollution, be responsible for asthma in children?

“…Young and co-workers for their comments on our recent article [1]. As we highlighted in our article, there are two recent reports indicating that single-nucleotide polymorphisms in the advanced glycosylation end product-specific receptor (AGER) gene, which encodes the receptor for advanced glycation end-products (RAGE), are associated with changes in measurements of airflow obstruction [2,3]. The findings reported by R.P.…”

“…In their study, they referred to the article of MCCONNELL et al [2] that showed a significant association between ''bronchitis symptoms'' and particulate matter only in the subset of asthmatic children who owned dogs. However, MCCONNELL et al [2] examined the relationship of both dog and cat ownership with air pollution, and reported that effects were somewhat greater among children who owned both a cat and a dog.…”

“…In their study, they referred to the article of MCCONNELL et al [2] that showed a significant association between ''bronchitis symptoms'' and particulate matter only in the subset of asthmatic children who owned dogs. However, MCCONNELL et al [2] examined the relationship of both dog and cat ownership with air pollution, and reported that effects were somewhat greater among children who owned both a cat and a dog. Since no evaluation of indoor levels of cat/dog allergens was carried out in that study, the stronger association observed between dog ownership and worsening of respiratory symptoms has been attributed to higher levels of indoor endotoxins associated with dog, in comparison to cat, ownership.…”