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J Allergy Clin Immunol. 2014 Sep;134(3):593-601.e12. doi: 10.1016/j.jaci.2014.04.018. Epub 2014 Jun 4.

Effects of early-life exposure to allergens and bacteria on recurrent wheeze and atopy in urban children.

Author information

1
Department of Medicine, University of California, San Francisco, Calif.
2
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Md. Electronic address: rwood@jhmi.edu.
3
Department of Pediatrics, Washington University School of Medicine and St Louis Children's Hospital, St Louis, Mo.
4
Division of Pediatric Allergy and Immunology, Columbia University Medical Center, New York, NY.
5
Pulmonary Center, Boston University School of Medicine, Boston, Mass.
6
Rho, Inc, Chapel Hill, NC.
7
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Md.
8
Division of Allergy and Immunology Henry Ford Health System, Detroit, Mich.
9
National Institute of Allergy and Infectious Diseases, Bethesda Md.
10
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass.
11
Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wis.

Abstract

BACKGROUND:

Wheezing illnesses cause major morbidity in infants and are frequent precursors to asthma.

OBJECTIVE:

We sought to examine environmental factors associated with recurrent wheezing in inner-city environments.

METHODS:

The Urban Environment and Childhood Asthma study examined a birth cohort at high risk for asthma (n = 560) in Baltimore, Boston, New York, and St Louis. Environmental assessments included allergen exposure and, in a nested case-control study of 104 children, the bacterial content of house dust collected in the first year of life. Associations were determined among environmental factors, aeroallergen sensitization, and recurrent wheezing at age 3 years.

RESULTS:

Cumulative allergen exposure over the first 3 years was associated with allergic sensitization, and sensitization at age 3 years was related to recurrent wheeze. In contrast, first-year exposure to cockroach, mouse, and cat allergens was negatively associated with recurrent wheeze (odds ratio, 0.60, 0.65, and 0.75, respectively; P ≤ .01). Differences in house dust bacterial content in the first year, especially reduced exposure to specific Firmicutes and Bacteriodetes, was associated with atopy and atopic wheeze. Exposure to high levels of both allergens and this subset of bacteria in the first year of life was most common among children without atopy or wheeze.

CONCLUSIONS:

In inner-city environments children with the highest exposure to specific allergens and bacteria during their first year were least likely to have recurrent wheeze and allergic sensitization. These findings suggest that concomitant exposure to high levels of certain allergens and bacteria in early life might be beneficial and suggest new preventive strategies for wheezing and allergic diseases.

KEYWORDS:

Asthma; allergen exposure; atopy; inner city; microbial exposure

Comment in

PMID:
24908147
PMCID:
PMC4151305
DOI:
10.1016/j.jaci.2014.04.018
[Indexed for MEDLINE]
Free PMC Article

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