Early Exposure to Dogs and Farm Animals and the Risk of Childhood Asthma | Asthma | JAMA Pediatrics | JAMA Network
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1.
Forsberg  B, Pekkanen  J, Clench-Aas  J,  et al.  Childhood asthma in four regions in Scandinavia: risk factors and avoidance effects.  Int J Epidemiol. 1997;26(3):610-619.PubMedGoogle ScholarCrossref
2.
Grabenhenrich  LB, Gough  H, Reich  A,  et al.  Early-life determinants of asthma from birth to age 20 years: a German birth cohort study.  J Allergy Clin Immunol. 2014;133(4):979-988.PubMedGoogle ScholarCrossref
3.
Lødrup Carlsen  KC, Roll  S, Carlsen  KH,  et al; GALEN WP 1.5 Birth Cohorts Working Group.  Does pet ownership in infancy lead to asthma or allergy at school age? pooled analysis of individual participant data from 11 European birth cohorts.  PLoS One. 2012;7(8):e43214. doi:10.1371/journal.pone.0043214.PubMedGoogle ScholarCrossref
4.
Chen  CM, Tischer  C, Schnappinger  M, Heinrich  J.  The role of cats and dogs in asthma and allergy—a systematic review.  Int J Hyg Environ Health. 2010;213(1):1-31.PubMedGoogle ScholarCrossref
5.
Apelberg  BJ, Aoki  Y, Jaakkola  JJ.  Systematic review: Exposure to pets and risk of asthma and asthma-like symptoms.  J Allergy Clin Immunol. 2001;107(3):455-460.PubMedGoogle ScholarCrossref
6.
Takkouche  B, González-Barcala  FJ, Etminan  M, Fitzgerald  M.  Exposure to furry pets and the risk of asthma and allergic rhinitis: a meta-analysis.  Allergy. 2008;63(7):857-864.PubMedGoogle ScholarCrossref
7.
Hesselmar  B, Aberg  N, Aberg  B, Eriksson  B, Björkstén  B.  Does early exposure to cat or dog protect against later allergy development?  Clin Exp Allergy. 1999;29(5):611-617.PubMedGoogle ScholarCrossref
8.
Chen  CM, Morgenstern  V, Bischof  W,  et al; Influences of Lifestyle Related Factors on the Human Immune System and Development of Allergies in Children (LISA) Study Group; German Infant Nutrition Intervention Programme (GINI) Study Group.  Dog ownership and contact during childhood and later allergy development.  Eur Respir J. 2008;31(5):963-973.PubMedGoogle ScholarCrossref
9.
Almqvist  C, Egmar  AC, Hedlin  G,  et al.  Direct and indirect exposure to pets—risk of sensitization and asthma at 4 years in a birth cohort.  Clin Exp Allergy. 2003;33(9):1190-1197.PubMedGoogle ScholarCrossref
10.
Almqvist  C, Garden  F, Kemp  AS,  et al; CAPS Investigators.  Effects of early cat or dog ownership on sensitisation and asthma in a high-risk cohort without disease-related modification of exposure.  Paediatr Perinat Epidemiol. 2010;24(2):171-178.PubMedGoogle ScholarCrossref
11.
Carlsten  C, Dimich-Ward  H, Becker  AB,  et al.  Indoor allergen exposure, sensitization, and development of asthma in a high-risk birth cohort.  Pediatr Allergy Immunol. 2010;21(4, pt 2):e740-e746. doi:10.1111/j.1399-3038.2010.01021.x.PubMedGoogle ScholarCrossref
12.
Brunekreef  B, Von Mutius  E, Wong  G, Odhiambo  J, García-Marcos  L, Foliaki  S; ISAAC Phase Three Study Group.  Exposure to cats and dogs, and symptoms of asthma, rhinoconjunctivitis, and eczema.  Epidemiology. 2012;23(5):742-750.PubMedGoogle ScholarCrossref
13.
Genuneit  J.  Exposure to farming environments in childhood and asthma and wheeze in rural populations: a systematic review with meta-analysis.  Pediatr Allergy Immunol. 2012;23(6):509-518.PubMedGoogle ScholarCrossref
14.
Ege  MJ, Mayer  M, Normand  AC,  et al; GABRIELA Transregio 22 Study Group.  Exposure to environmental microorganisms and childhood asthma.  N Engl J Med. 2011;364(8):701-709.PubMedGoogle ScholarCrossref
15.
Örtqvist  AK, Lundholm  C, Wettermark  B, Ludvigsson  JF, Ye  W, Almqvist  C.  Validation of asthma and eczema in population-based Swedish drug and patient registers.  Pharmacoepidemiol Drug Saf. 2013;22(8):850-860.PubMedGoogle ScholarCrossref
16.
 Hundar, Katter och andra sällskapsdjur. Report from Statistics Sweden. http://www.skk.se/Global/Dokument/Om-SKK/SCB-undersokning-Hundar-katter-och-andra-sallskapsdjur-2012.pdf. Accessed May 15, 2015.
17.
 Yearbook of Agricultural Statistics: including food statistics. Statistics Sweden, http://webbutiken.jordbruksverket.se/sv/artiklar/jo01br1401.html. June 26, 2014. Accessed March 1, 2015.
18.
Lodge  CJ, Allen  KJ, Lowe  AJ,  et al.  Perinatal cat and dog exposure and the risk of asthma and allergy in the urban environment: a systematic review of longitudinal studies.  Clin Dev Immunol. 2012;2012:176484 doi:10.1155/2012/176484.Google ScholarCrossref
19.
Ownby  DR, Johnson  CC, Peterson  EL.  Exposure to dogs and cats in the first year of life and risk of allergic sensitization at 6 to 7 years of age.  JAMA. 2002;288(8):963-972.PubMedGoogle ScholarCrossref
20.
Almqvist  C, Egmar  AC, van Hage-Hamsten  M,  et al.  Heredity, pet ownership, and confounding control in a population-based birth cohort.  J Allergy Clin Immunol. 2003;111(4):800-806.PubMedGoogle ScholarCrossref
21.
Daley  D.  The evolution of the hygiene hypothesis: the role of early-life exposures to viruses and microbes and their relationship to asthma and allergic diseases.  Curr Opin Allergy Clin Immunol. 2014;14(5):390-396.PubMedGoogle ScholarCrossref
22.
Strachan  DP.  Hay fever, hygiene, and household size.  BMJ. 1989;299(6710):1259-1260.PubMedGoogle ScholarCrossref
23.
Konya  T, Koster  B, Maughan  H,  et al; CHILD Study Investigators.  Associations between bacterial communities of house dust and infant gut.  Environ Res. 2014;131:25-30.PubMedGoogle ScholarCrossref
24.
Fujimura  KE, Demoor  T, Rauch  M,  et al.  House dust exposure mediates gut microbiome Lactobacillus enrichment and airway immune defense against allergens and virus infection.  Proc Natl Acad Sci U S A. 2014;111(2):805-810.PubMedGoogle ScholarCrossref
25.
Gisel  JJ, Brumble  LM, Johnson  MM.  Bordetella bronchiseptica pneumonia in a kidney-pancreas transplant patient after exposure to recently vaccinated dogs.  Transpl Infect Dis. 2010;12(1):73-76.PubMedGoogle ScholarCrossref
26.
Myers  EM, Ward  SL, Myers  JP.  Life-threatening respiratory pasteurellosis associated with palliative pet care.  Clin Infect Dis. 2012;54(6):e55-e57. doi:10.1093/cid/cir975.PubMedGoogle ScholarCrossref
27.
Shrikrishna  D, de la Rua-Domenech  R, Smith  NH, Colloff  A, Coutts  I.  Human and canine pulmonary Mycobacterium bovis infection in the same household: re-emergence of an old zoonotic threat?  Thorax. 2009;64(1):89-91.PubMedGoogle ScholarCrossref
28.
Grad  R, Morgan  WJ.  Long-term outcomes of early-onset wheeze and asthma.  J Allergy Clin Immunol. 2012;130(2):299-307.PubMedGoogle ScholarCrossref
29.
Wlasiuk  G, Vercelli  D.  The farm effect, or: when, what and how a farming environment protects from asthma and allergic disease.  Curr Opin Allergy Clin Immunol. 2012;12(5):461-466.PubMedGoogle ScholarCrossref
30.
Loss  G, Apprich  S, Waser  M,  et al.  The protective effect of farm milk consumption on childhood asthma and atopy: the GABRIELA study.  J Allergy Clin Immunol. 2011;128(4):766-773.e4. PubMedGoogle ScholarCrossref
31.
Naleway  AL.  Asthma and atopy in rural children: is farming protective?  Clin Med Res. 2004;2(1):5-12.PubMedGoogle ScholarCrossref
32.
Almqvist  C, Pershagen  G, Wickman  M.  Low socioeconomic status as a risk factor for asthma, rhinitis and sensitization at 4 years in a birth cohort.  Clin Exp Allergy. 2005;35(5):612-618. PubMedGoogle ScholarCrossref
33.
Ludvigsson  JF, Andersson  E, Ekbom  A,  et al.  External review and validation of the Swedish national inpatient register.  BMC Public Health. 2011;11:450.PubMedGoogle ScholarCrossref
Original Investigation
November 2, 2015

Early Exposure to Dogs and Farm Animals and the Risk of Childhood Asthma

Author Affiliations
  • 1Department of Medical Sciences, Molecular Epidemiology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
  • 2Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
  • 3Clinical Epidemiology and Biostatistics, Faculty of Medicine and Health, Örebro University, Örebro, Sweden
  • 4School of Health and Medical Sciences, Örebro University, Örebro, Sweden
  • 5Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
  • 6Centre for Molecular Medicine, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden
  • 7Astrid Lindgren Children’s Hospital, Lung and Allergy Unit, Karolinska University Hospital, Stockholm, Sweden
JAMA Pediatr. 2015;169(11):e153219. doi:10.1001/jamapediatrics.2015.3219
Abstract

Importance  The association between early exposure to animals and childhood asthma is not clear, and previous studies have yielded contradictory results.

Objective  To determine whether exposure to dogs and farm animals confers a risk of asthma.

Design, Setting and Participants  In a nationwide cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden from January 1, 2001, to December 31, 2010 (N = 1 011 051), using registry data on dog and farm registration, asthma medication, diagnosis, and confounders for parents and their children. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for school-aged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. Data were analyzed from January 1, 2007, to September 30, 2012.

Exposures  Living with a dog or farm animal.

Main Outcomes and Measures  Childhood asthma diagnosis and medication used.

Results  Of the 1 011 051 children born during the study period, 376 638 preschool-aged (53 460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276 298 school-aged children (22 629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18 799 children (5.0%) in the preschool-aged children’s cohort experienced an asthmatic event before baseline, and 28 511 cases of asthma and 906 071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children’s cohort, 11 585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.81-0.93) and in preschool-aged children 3 years or older (HR, 0.90; 95% CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Results were comparable when analyzing only first-born children. Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95% CI, 0.31-0.76, and HR, 0.69; 95% CI, 0.56-0.84), respectively.

Conclusions and Relevance  In this study, the data support the hypothesis that exposure to dogs and farm animals during the first year of life reduces the risk of asthma in children at age 6 years. This information might be helpful in decision making for families and physicians on the appropriateness and timing of early animal exposure.

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