Systematic review: Exposure to pets and risk of asthma and asthma-like symptoms

doi:10.1067/mai.2001.113240

Journal of Allergy and Clinical Immunology

Volume 107, Issue 3, March 2001, Pages 455-460

https://doi.org/10.1067/mai.2001.113240 Get rights and content

Abstract

Background: Studies of exposure to pets and risk of asthma have yielded conflicting results. Objectives: We performed a systematic review to synthesize the evidence of the effect of exposure to pets in the home on the risk of asthma and asthma-related symptoms. We also assessed differences between the studies as sources of heterogeneity of the results. Methods: We conducted a MEDLINE search (until the end of 1999) using the following boolean search command: (asthma[all] OR wheez*[all]) AND (domestic animal*[all] OR pets[all]). The outcome was limited to either diagnosis of asthma or the symptom of wheezing. The exposure of interest was domestic animals in the home. Appropriate temporal relationship was defined as present in studies with either pet keeping within the first 2 years of life, in the past, or exposure to pets preceding the outcome. Results: Thirty-two of the 217 retrieved articles fulfilled the eligibility criteria. Inappropriate time sequence of the exposure and outcome information was an important source of heterogeneity and an indication of potential selection bias. Therefore we analyzed studies focusing on early exposure or ensuring appropriate temporal sequence. The pooled risk estimates for both asthma (fixed-effects odds ratio, 1.11; 95% CI, 0.98-1.25; heterogeneity, P = .04; random-effects odds ratio, 1.09; 95% CI, 0.89-1.34) and wheezing (fixed-effects odds ratio, 1.19; 95% CI, 1.05-1.35; heterogeneity, P = .03; random-effects odds ratio, 1.17; 95% CI, 0.95-1.44) indicated a small effect, which was limited to studies with a median study population age of over 6 years (fixed-effects odds ratio, 1.19; 95% CI, 1.02-1.40; heterogeneity, P = .04; random-effects odds ratio, 1.15; 95% CI, 0.86-1.56; fixed-effects odds ratio, 1.29; 95% CI, 1.12-1.48; heterogeneity, P = .31). In younger children the harmful effect disappeared for wheezing (odds ratio, 0.80; 95% CI, 0.59-1.08; P = .38). Conclusion: Exposure to pets appears to increase the risk of asthma and wheezing in older children. The observed lower risk among exposed than among unexposed young children is consistent with a protective effect in this age group but could also be explained by selection bias. (J Allergy Clin Immunol 2001;107:455-60.)

Section snippets

Selection criteria and data collection

We performed a search of the MEDLINE database using the following boolean search command: (asthma[all] OR wheez*[all]) AND (domestic animal*[all] OR pets[all]).

From this list, we chose only cross-sectional, case-control, or cohort studies, excluding letters, comments, reviews, and ecological studies. The outcome was limited to either diagnosis of asthma, with or without verification of medical records, or the symptom of wheezing. The exposure of interest was domestic animals in the home,

Selected studies

The MEDLINE search retrieved 217 articles to which selection criteria were applied. After searching the abstracts, full text, or both of the studies, 32 studies were included in the analysis. Reasons for removal included failure of exposure or outcome to meet the aforementioned criteria, presence of only data for select subpopulations, lack of an appropriate control group (eg, severity of symptoms in asthmatic subjects), and presentation of inconsistent data. We contacted authors of 4 of the

Discussion

The present analysis indicates that problems related to study design may have compromised some previous studies of the relation between exposure to pets and asthma or related symptoms. Our results showed that restriction to analyses of studies that took into account the potential for bias resulted in a reduction in heterogeneity between studies. Although it is not possible to precisely quantify the risks to children associated with exposure to pets, this analysis showed a slightly elevated

References (48)

TAE Platts-Mills et al.
Dust mite allergens and asthma: a worldwide problem
J Allergy Clin Immunol
(1989)
R DerSimonian et al.
Meta-analysis in clinical trials
Control Clin Trials
(1986)
P Plaschke et al.
Association between atopic sensitization and asthma and bronchial hyperresponsiveness in Swedish adults: Pets, and not mites, are the most important allergens
J Allergy Clin Immunol
(1999)
K Noertjojo et al.
Exposure and sensitization to cat dander: asthma and asthma-like symptoms among adults
J Allergy Clin Immunol
(1999)
SM Tariq et al.
The prevalence of and risk factors for atopy in early childhood: a whole population birth cohort study
J Allergy Clin Immunol
(1998)
HP Roost et al.
Role of current and childhood exposure to cat and atopic sensitization
J Allergy Clin Immunol
(1999)
R Sporik et al.
Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood
N Engl J Med
(1990)
DL Rosenstreich et al.
The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma
N Engl J Med
(1997)
A Ahlbom et al.
NORDPET: Pets indoors—a risk factor for or protection against sensitization/allergy
Indoor Air
(1998)
TAE Platts-Mills et al.
The role of allergy and atopy in asthma
Curr Opin Pulm Med
(1996)

B Brunekreef et al.

Pets, allergy and respiratory symptoms in children

Int J Epidemiol

(1992)

A Bener et al.

Pets, allergy and respiratory symptoms in children living in a desert country

Allerg Immunol (Paris)

(1995)

B Hesselmar et al.

Does early exposure to cat or dog protect against later allergy development?

Clin Exp Allergy

(1999)

S. Greenland

Quantitative methods in the review of epidemiologic literature

Epidemiol Rev

(1987)

S Sharp et al.

sbe16.1 : New syntax and output for the meta-analysis command

StataCorp

Stata statistical software: release 6.0

(1999)

S. Sharp et al.

Meta-analysis regression

CB Begg et al.

Operating characteristics of a rank correlation test for publication bias

Biometrics

(1994)

T Steichen et al.

sbe19.1: Tests for publication bias in meta-analysis

HR Hosein et al.

The effect of domestic factors on respiratory symptoms and FEV₁

Int J Epidemiol

(1989)

LJ Horwood et al.

Social and familial factors in the development of early childhood asthma

Pediatrics

(1985)

AR Al Frayh et al.

Epidemiology of asthma and allergic rhinitis in two coastal regions of Saudi Arabia

Allerg Immunol (Paris)

(1989)

L Nilsson et al.

Allergic disease in teenagers in relation to urban or rural residence at various stages of childhood

Allergy

(1999)

MP Kane et al.

Unlimited opportunities for environmental interventions with inner-city asthmatics

J Asthma

(1999)

Cited by (197)

Indoor air pollution is associated with respiratory symptoms in children in urban Vietnam
2024, Science of the Total Environment
Exposure to indoor air pollution (IAP) is a leading environmental risk for respiratory diseases. We investigated the relationship between respiratory symptoms and polluting indoor activities such as smoking, cooking and contact with pets among children in Ho Chi Minh City (HCMC), Vietnam. A cross-sectional survey applied a multistage sampling method in 24 randomly selected secondary schools across the city. Approximately 15,000 students completed self-administrated questionnaires on risk factors and respiratory health outcomes within the preceding 12 months. Data were analyzed using a multivariable logistic regression model with robust standard errors. Wheeze was the most common respiratory symptom (39.5 %) reported, followed by sneezing and runny nose (28.3 %). A small percentage of students self-reported asthma (8.6 %). Approximately 56 % of participants lived with family members who smoked. A positive association between exposure to indoor secondhand smoke and respiratory symptoms was observed, with adjusted odds ratios (aOR) of 1.41 (95 % CI: 1.25–1.60, p < 0.001) for wheezing and 1.64 (95 % CI: 1.43–1.87, p < 0.001) for sneezing and runny nose, respectively. Using an open stove fuelled by coal, wood, or kerosene for cooking was associated with wheeze (aOR: 1.36, CI 95 %: 1.10–1.68, p = 0.01) and sneezing and runny nose (aOR: 1.36, CI 95 %: 1.09–1.69, p = 0.01). In the present study, IAP was associated with adverse health outcomes, as evidenced by an increase in respiratory symptoms reported within the previous 12 months.
Bird ownership and pulmonary outcomes apart from hypersensitivity pneumonitis in European older adults
2023, Respiratory Medicine and Research
Exposure to birds has been linked with several lung pathologies and especially hypersensitivity pneumonitis, but discordant literature exist on the potential effects of this exposure on other respiratory pathologies.
This study aims to examine the associations between bird ownership and asthma, lung cancer, and chronic obstructive pulmonary disease (COPD) in older European adults.
A total of 28,109 participants from the Survey of Health, Ageing, and Retirement in Europe were employed and analyzed with multivariate logistic regressions.
No association was found with asthma or lung cancer. Bird ownership increased the odds for COPD diagnosis (OR=1.30; 95 % CI: 1.12–1.51) and more so in males (OR=1.53; 95 % CI: 1.25–1.87) after adjustment for demographic, respiratory, lifestyle, and socioeconomic factors. Male bird owners who smoke had an even more increased risk compared to non-smokers, as did those who lived in multi-person households compared to those living alone.
Conclusion: Bird ownership may be positively associated with COPD in older European males.
Associations of early-life pet ownership with asthma and allergic sensitization: A meta-analysis of more than 77,000 children from the EU Child Cohort Network
2022, Journal of Allergy and Clinical Immunology
Studies examining associations of early-life cat and dog ownership with childhood asthma have reported inconsistent results. Several factors could explain these inconsistencies, including type of pet, timing, and degree of exposure.
Our aim was to study associations of early-life cat and dog ownership with asthma in school-aged children, including the role of type (cat vs dog), timing (never, prenatal, or early childhood), and degree of ownership (number of pets owned), and the role of allergic sensitization.
We used harmonized data from 77,434 mother-child dyads from 9 birth cohorts in the European Union Child Cohort Network when the child was 5 to 11 years old. Associations were examined through the DataSHIELD platform by using adjusted logistic regression models, which were fitted separately for each cohort and combined by using random effects meta-analysis.
The prevalence of early-life cat and dog ownership ranged from 12% to 45% and 7% to 47%, respectively, and the prevalence of asthma ranged from 2% to 20%. There was no overall association between either cat or dog ownership and asthma (odds ratio [OR] = 0.97 [95% CI = 0.87-1.09] and 0.92 [95% CI = 0.85-1.01], respectively). Timing and degree of ownership did not strongly influence associations. Cat and dog ownership were also not associated with cat- and dog-specific allergic sensitization (OR = 0.92 [95% CI = 0.75-1.13] and 0.93 [95% CI = 0.57-1.54], respectively). However, cat- and dog-specific allergic sensitization was strongly associated with school-age asthma (OR = 6.69 [95% CI = 4.91-9.10] and 5.98 [95% CI = 3.14-11.36], respectively). There was also some indication of an interaction between ownership and sensitization, suggesting that ownership may exacerbate the risks associated with pet-specific sensitization but offer some protection against asthma in the absence of sensitization.
Our findings do not support early-life cat and dog ownership in themselves increasing the risk of school-age asthma, but they do suggest that ownership may potentially exacerbate the risks associated with cat- and dog-specific allergic sensitization.
The role of environmental allergen control in the management of asthma
2022, World Allergy Organization Journal
Citation Excerpt :
Several studies, mainly in adults, have investigated the direct impact of cat allergen exposure on asthma symptoms, using different challenge techniques.86–89 In general, cat allergen challenges produced both clinical and biomarker responses, suggesting a potential implication of cat exposure in asthma morbidity.90,91 The general current approach is avoidance, ie, taking the cat away from home.
Allergen exposure may exacerbate asthma symptoms in sensitized patients. Allergen reduction or avoidance measures have been widely utilized; however, there is ongoing controversy on the effectiveness of specific allergen control measures in the management of children with asthma. Often, allergen avoidance strategies are not recommended by guidelines because they can be complex or burdensome, although individual patients may benefit. Here we explore the potential for intervention against exposure to the major allergens implicated in asthma (ie, house dust mites, indoor molds, rodents, cockroaches, furry pets, and outdoor molds and pollens), and subsequent effects on asthma symptoms. We critically assess the available evidence regarding the clinical benefits of specific environmental control measures for each allergen. Finally, we underscore the need for standardized and multifaceted approaches in research and real-life settings, which would result in the identification of more personalized and beneficial prevention strategies.
Decreasing ten-year (2008–2018) trends of the prevalence of childhood asthma and air pollution in Southern Taiwan
2021, World Allergy Organization Journal
Citation Excerpt :
The authors suggested that breastfeeding-related reductions in childhood wheezing might relate to the known beneficial immunological factors that could reduce childhood viral infections that predispose individuals to asthma.10,17 The roles of pet keeping on childhood asthma and respiration-symptoms also remained controversial.8,9,20,21 Luo et al found pet keeping early were positively associated with current wheezing and current dry cough; pet keeping currently were positively associated with current wheezing and diagnosed asthma.22
Asthma is a common pediatric chronic respiratory disease worldwide. Previous studies showed the prevalence of childhood asthma increased in developed countries as well as in Taiwan in the late 20th century. Recently, several reports from different parts of the world showed a reversed trend in this epidemic of childhood asthma prevalence. This study investigated the trend of childhood asthma through serial cross-section questionnaire surveys in the southern part of Taiwan, and identified associated factors related to this trend in elementary school children.
We used the Chinese version of the International Study of Asthma and Allergies in Childhood (ISAAC)²⁹ questionnaire to assess the asthma status of elementary school students aged 6–12 years in Tainan city in 3 independent study periods, namely, 2008–2009, 2010–2012, and 2017–2018. We assessed the trend of “asthma” and “related respiratory symptoms” across 3 study periods.
Of the 19,633 respondents, 17,545 (89.4%) completed the questionnaires. After adjustment for covariates, the prevalence of asthma and related respiratory symptoms was significantly lower in 2017–2018 than in the 2 earlier periods. Among the protective factors, the increasing rate of breastfeeding might be partly responsible for the observed reduced prevalence of current asthma and exercise-induced wheeze, but not physician-diagnosed asthma. The presence of pets in the house was the risk factor that correlated with the prevalence of nocturnal cough. Pearson correlation analysis showed a significant correlation of the prevalence of physician-diagnosed asthma, current asthma, and exercise-induced wheezing with the concentrations of air pollutant particles with aerodynamic diameter ≤10 μM (PM₁₀) (r = 0.84, 0.77 and 0.81, respectively).
The prevalence of asthma and related respiratory symptoms has declined in elementary school-age children in southern Taiwan. The increased prevalence of breastfeeding, decreased rate of the presence of pets in the house, and improvement in outdoor air pollution seem to be related to this decreasing trend of asthma in school children. Our findings will provide the scientific base to empower prevention policy to reverse the trend of childhood asthma prevalence.
N/A
The time window of pet ownership exposure modifies the relationship of Environmental Tobacco Smoke with lung function: A large population-based cohort study
2020, Environmental Research
There is a large body of evidence linking Environmental Tobacco Smoke (ETS) exposure with impaired lung function. However, it is not known whether exposure to pets modifies this relationship. To investigate if pet ownership changes the association between ETS exposure and lung function, a population-based sample of 7326 children, 7–14 years old, were randomly recruited from 24 districts in northeast China. Lung function including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), peak expiratory flow (PEF), and maximal mid-expiratory flow (MMEF) was measured by spirometry, while pet ownership time periods and ETS exposure were collected by questionnaire. Two-level regression analysis was done, with covariates controlled for. The results showed pet exposure in certain early lifetime windows modified the associations of ETS exposure on decreased lung function in children. Among children exposed to current ETS, those exposed to pets in utero had greater reductions in lung function (for instance: OR for reduced FVC (<85% predicted) = 10.86; 95% CI: 3.80–30.97) than those not exposed to pets in utero (OR = 2.32; 95% CI: 1.76–3.05) (p_interaction = 0.005). While, children exposed to current pet ownership reduced the lung function impairment induced by ETS exposure during the first 2 years of life and/or ETS exposure during pregnancy, especially for FVC impairment. For instance, OR (95%CI) for reduced FVC (<85% predicted) was 0.81 (0.56, 1.18) and 1.42 (1.15, 1.74), respectively, for children with or without current pet ownership exposed to ETS during the first 2 years of life (p_interaction = 0.010). Furthermore, pet type or number of pets did not significantly modify associations between ETS exposure and lung function. In conclusion, the timing of pet ownership modified associations between ETS exposure and lung function, pet ownership in utero and during the first 2 years of life significantly worsened the adverse impacts of passive smoking on lung function.

View all citing articles on Scopus

^☆: Reprint requests: Jouni J. K. Jaakkola, MD, PhD, Environmental Health Program, The Nordic School of Public Health, PO Box 12133, SE-402 42 Göteborg, Sweden.

View full text

Asthma, Rhinitis, Other Respiratory DiseasesSystematic review: Exposure to pets and risk of asthma and asthma-like symptoms☆

Abstract

Section snippets

Selection criteria and data collection

Selected studies

Discussion

J Allergy Clin Immunol

Control Clin Trials

J Allergy Clin Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

J Allergy Clin Immunol

Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood

N Engl J Med

The role of cockroach allergy and exposure to cockroach allergen in causing morbidity among inner-city children with asthma

N Engl J Med

NORDPET: Pets indoors—a risk factor for or protection against sensitization/allergy

Indoor Air

The role of allergy and atopy in asthma

Curr Opin Pulm Med

Pets, allergy and respiratory symptoms in children

Int J Epidemiol

Pets, allergy and respiratory symptoms in children living in a desert country

Allerg Immunol (Paris)

Does early exposure to cat or dog protect against later allergy development?

Clin Exp Allergy

Quantitative methods in the review of epidemiologic literature

Epidemiol Rev

sbe16.1 : New syntax and output for the meta-analysis command

Stata statistical software: release 6.0

Meta-analysis regression

Operating characteristics of a rank correlation test for publication bias

Biometrics

sbe19.1: Tests for publication bias in meta-analysis

The effect of domestic factors on respiratory symptoms and FEV1

Int J Epidemiol

Social and familial factors in the development of early childhood asthma

Pediatrics

Epidemiology of asthma and allergic rhinitis in two coastal regions of Saudi Arabia

Allerg Immunol (Paris)

Allergic disease in teenagers in relation to urban or rural residence at various stages of childhood

Allergy

Unlimited opportunities for environmental interventions with inner-city asthmatics

J Asthma

Asthma, Rhinitis, Other Respiratory Diseases
Systematic review: Exposure to pets and risk of asthma and asthma-like symptoms☆

The effect of domestic factors on respiratory symptoms and FEV₁