Early exposure to children in family and day care as related to adult asthma and hay fever: results from the European Community Respiratory Health Survey
Early exposure to children in family and day care as related to adult asthma
and hay fever: results from the European Community Respiratory Health Survey
C Svanes1, D Jarvis2,
S Chinn2, E Omenaas1, A
Gulsvik1 and P Burney2 for the
European Community Respiratory Health Survey
1 Department of Thoracic Medicine, University of
Bergen, 5021 Bergen, Norway 2 Department of Public Health Sciences, Kings College London, London
SE1 3QD, UK
Correspondence to:
Dr C Svanes, Department of Medicine, Haraldsplass Hospital, 5009 Bergen, Norway; cecilie.svanes@haraldsplass.no
Background: The literature indicates that early exposure tochildren in the family and to day care permanently influences
the development of allergic disease. A study was undertakento
examine the associations of family size and day care withadult
asthma and hay fever and to determine whether these associationsare
mediated through specific IgE production and whether theyvary with
allergic predisposition.
Methods: 18 530 subjects aged 2044 years from 36 areas
predominantly in the market economies participated in the European
Community Respiratory Health Survey and provided informationthrough
interviewer-led questionnaires. 13 932 subjects gaveblood samples
for measurement of specific IgE.
Results: Hay fever was less common in subjects with many siblings(OR=0.92; 95% CI 0.90 to 0.95 per sib). There was a U-shaped
relationship between asthma and number of siblings (quadraticeffect
of siblings, pwheeze=0.014, pFEV1=0.016). In subjects
without siblings but exposed to children in day care, hay feverwas
less common (OR=0.76; 95% CI 0.60 to 0.98) and asthma symptomswere
more common (ORwheeze=1.48; 95% CI 1.12 to 1.95). Adjustmentfor
specific IgEs did not alter these associations. The inverse
association of hay fever with siblings was found in sensitised
subjects (OR=0.89; 95% CI 0.84 to 0.94) and in those with parental
allergy (OR=0.91; 95% CI 0.85 to 0.97), but not in subjectswithout
such a predisposition (OR=1.02; 95% CI 0.97 to 1.09).
Conclusion: Subjects exposed to many children at home or in
day care experienced less hay fever and more asthma in adulthood.
Microbial challenge through children may contribute to a non-allergic
immunological development giving less hay fever but more airways
infections predisposing to asthma. These effects were not mediated
through production of specific IgE. The protective effect ofsiblings
on hay fever was particularly strong in those withan allergic
predisposition.
Keywords: hygiene hypothesis; atopy; asthma; hay fever
ALL INFORMATION, DATA, AND
MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION
PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS
OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR
LEGAL ADVICE. THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND
COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH
YOUR HEALTH CARE PROVIDER.
"A foolish faith in authority is the worst enemy of truth."
-- Albert Einstein, letter to a friend, 1901
"I know of no safe depository of the ultimate powers of the society but the people themselves, and if we think them not enlightened enough to exercise control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education."
-- Thomas Jefferson, letter to William C. Jarvis, September 28, 1820
"What's the point of vaccination if it doesn't protect you from the unvaccinated?"
-- Sandy Gottstein
"Who gets to decide what the greater good is and how many will be sacrificed to it?"