Cat study. Early exposure to cats may help prevent allergies in later life.

Cat Allergies Study
Contributors: Dennis R. Ownby, M.D.; Christine Cole Johnson, Ph.D; Edward L. Peterson Ph.D.

Exposure to Dogs and Cats in the First Year of Life and Risk of Allergic Sensitization at 6 to 7 Years of Age.
Abstract Contributed by Murray Grossan M.D. at Hydromedonline.com

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.

Author/Article Information
Author Affiliations: Section of Allergy and Immunology, Department of Pediatrics, Medical College of Georgia, Augusta (Dr Ownby); Department of Biostatistics and Research Epidemiology, Henry Ford Health System, Detroit, Mich (Drs Johnson and Peterson); National Institute of Environmental Health Sciences Center in Molecular and Cellular Toxicology with Human Applications, Wayne State University, Detroit (Drs Johnson and Peterson).

Corresponding Author and Reprints: Dennis R. Ownby, MD, Section of Allergy and Immunology, Department of Pediatrics, BG-1019, Medical College of Georgia, Augusta, GA 30912-3790 (e-mail: downby@mail.mcg.edu).

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