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 Aug 28;288(8):963-72. doi: 10.1001/jama.288.8.963.

Abstract

Context: Childhood asthma is strongly associated with allergic sensitization. Studies have suggested that animal exposure during infancy reduces subsequent allergic sensitization.

Objective: To evaluate the relationship between dog and cat exposure in the first year of life and allergic sensitization at 6 to 7 years of age.

Design, setting, and subjects: Prospective birth cohort study of healthy, full-term infants enrolled in a health maintenance organization in suburban Detroit, Mich, who were born between April 15, 1987, and August 31, 1989, and followed up yearly to a mean age of 6.7 years. Of 835 children initially in the study at birth, 474 (57%) completed follow-up evaluations at age 6 to 7 years.

Main outcome measures: Atopy, defined as any skin prick test positivity to 6 common aeroallergens (dust mites [Dermatophagoides farinae, D pteronyssinus], dog, cat, short ragweed [Ambrosia artemisiifolia], and blue grass [Poa pratensis]); seroatopy, defined as any positive allergen-specific IgE test result for the same 6 allergens or for Alternaria species.

Results: The prevalence of any skin prick test positivity (atopy) at age 6 to 7 years was 33.6% with no dog or cat exposure in the first year of life, 34.3% with exposure to 1 dog or cat, and 15.4% with exposure to 2 or more dogs or cats (P =.005). The prevalence of any positive allergen-specific IgE test result (seroatopy) was 38.5% with no dog or cat exposure, 41.2% with exposure to 1 dog or cat, and 17.9% with exposure to 2 or more dogs or cats (P =.003). After adjustment for cord serum IgE concentration, sex, older siblings, parental smoking, parental asthma, bedroom dust mite allergen levels at 2 years, and current dog and cat ownership, exposure to 2 or more dogs or cats in the first year of life was associated with a significantly lower risk of atopy (adjusted odds ratio, 0.23; 95% confidence interval, 0.09-0.60) and seroatopy (adjusted odds ratio, 0.33; 95% confidence interval, 0.13-0.83).

Conclusion: Exposure to 2 or more dogs or cats in the first year of life may reduce subsequent risk of allergic sensitization to multiple allergens during childhood.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Allergens / immunology*
  • Animals
  • Asthma / epidemiology
  • Asthma / immunology
  • Cats / immunology*
  • Child
  • Child, Preschool
  • Dogs / immunology*
  • Environmental Exposure*
  • Female
  • Follow-Up Studies
  • Humans
  • Hypersensitivity / epidemiology
  • Hypersensitivity / immunology*
  • Infant
  • Male
  • Prospective Studies
  • Skin Tests

Substances

  • Allergens