Relationship of house-dust mite allergen exposure in children's bedrooms in infancy to bronchial hyperresponsiveness and asthma diagnosis by age 6 to 7.
BACKGROUND
Several studies have suggested that exposure to house-dust mite (HDM) allergen in infancy increases the risk of developing asthma.


OBJECTIVE
To determine whether exposure to higher levels of dust mite in infants increased the risk of developing bronchial hyperresponsiveness (BHR) or physician-diagnosed asthma by age 6 to 7 years.


METHODS
A health maintenance organization-based cohort of 97 middle class suburban children born from 1987 to 1989 with a high cord blood immunoglobulin E, defined as > or = 0.56 IU/mL, was followed as a part of the Childhood Allergy Study. During the first 2 years of life, monthly bedroom dust samples were collected and analyzed for Der f 1 and Der p 1. Between 6 and 7 years of age, 64 of the original cohort answered a questionnaire used to determine the presence of physician-diagnosed asthma, underwent clinical examination, skin prick testing, and methacholine inhalation challenge. Mann-Whitney tests were used to compare Der f 1 and Der p 1 levels in homes of children with and without BHR, and those with and without physician-diagnosed asthma.


RESULTS
In all, 1,421 dust samples were collected and assayed. No significant differences were seen in either the mean, maximum, or minimum dust mite allergen levels in homes of children with versus without BHR, or children with versus without asthma. However, sensitization to HDM was associated with physician-diagnosed asthma (P < 0.05).


CONCLUSIONS
When compared with other studies, we were able to more accurately estimate the level of dust mite allergen exposure through repeated sampling over a relatively long period, incorporating seasonal variations. Although HDM sensitization and asthma were concurrently related, we were unable to find any relationship between level of HDM allergen exposure in children's bedrooms in early childhood and development of BHR or physician-diagnosed asthma by age 6 to 7 years.
Carter
Paul M
PM
Henry Ford Health System, Division of Allergy, Detroit, Michigan, USA. pmcmd@att.net
Peterson
Edward L
EL
Ownby
Dennis R
DR
Zoratti
Edward M
EM
Johnson
Christine C
CC
D000328:Adult; D016902:Air Pollution, Indoor / Q000032:analysis*; D000485:Allergens / Q000009:adverse effects*; D039741:Antigens, Dermatophagoides / Q000009:adverse effects*; D060829:Arthropod Proteins; D001249:Asthma / Q000175:diagnosis* / Q000209:etiology*; D001512:Bedding and Linens; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000209:etiology*; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D002669:Child Welfare; D002675:Child, Preschool; D015331:Cohort Studies; D003546:Cysteine Endopeptidases; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D005260:Female; D005312:Fetal Blood / Q000276:immunology / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007229:Infant Welfare; D007231:Infant, Newborn; D008297:Male; D008429:Maternal Welfare; D016210:Methacholine Chloride; D012882:Skin Tests; D013223:Statistics as Topic
D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D016085:Bronchoconstrictor Agents; D007070:Immunoglobulin A; D016210:Methacholine Chloride; D007073:Immunoglobulin E; D003546:Cysteine Endopeptidases; C451159:Dermatophagoides farinae antigen f 1; C451162:Dermatophagoides pteronyssinus antigen p 1