Childhood exposure to infection and risk of adult onset wheeze and atopy
- C Bodnera,
- W J Andersonb,
- T S Reidc,
- D J Godden on behalf of the Aberdeen WHEASE Study Groupa,b
- aDepartment of Environmental and Occupational Medicine, University of Aberdeen, Aberdeen AB25 2ZD, UK, bDepartment of Thoracic Medicine, Aberdeen Royal Infirmary, Aberdeen AB25 2ZN, UK, cDepartment of Medical Microbiology, Grampian University Hospitals Trust, Aberdeen AB25 2ZN, UK
- Dr D J Godden, Department of Environmental and Occupational Medicine, University of Aberdeen, Aberdeen AB25 2ZD email: d.j.godden{at}abdn.ac.uk
- Received 15 September 1999
- Revision requested 11 November 1999
- Revised 5 January 2000
- Accepted 27 January 2000
Abstract
BACKGROUND The prevalence of asthma and allergic diseases in children and young adults is inversely associated with family size. It has been suggested that more frequent exposure to infections in a large family group, particularly those spread by the faecal-oral route, may protect against atopic diseases, although not all published data support this hypothesis. Whether similar considerations apply to adult onset wheeze is unknown. The relationship between adult onset wheezing and atopy measured in adulthood and childhood exposure to a range of infections was investigated.
METHODS A nested case control study of participants in a 30 year follow up survey was conducted. Questionnaire data on childhood infections had been obtained in a 1964 survey. In 1995 a further questionnaire on respiratory symptoms and other risk factors for wheezing illness was administered, total IgE, skin and RAST tests were performed, and serum was stored. In 1999 serological tests for hepatitis A,Helicobacter pylori, andToxoplasma gondii were performed on the stored samples. Information from the 1964 questionnaires was available for 97 cases and 208 controls and serological tests were obtained for 85 cases and 190 controls. The potential risk factors were examined for all cases, those who reported doctor diagnosed asthma, those who described persistent cough and phlegm with wheeze, and subjects stratified by atopic status.
RESULTS The sibship structure was similar in cases and controls. In univariate analysis of all cases, childhood infections reported by parents as acquired either before or after the age of three years did not influence case:control or atopic status. Seropositivity was also similar for all cases and controls, but cases in the subgroup with chronic cough and phlegm were more likely to be seropositive for hepatitis A andH pylori. Seropositivity was unrelated to atopic status. In multivariate analyses both the effect of having two or more younger siblings (OR 0.1, 95% CI 0.03 to 0.8) and of acquiring measles up to the age of three (OR 0.2, CI 0.03 to 0.8) were significantly related to a lower risk of doctor diagnosed asthma.
CONCLUSIONS In these well characterised subjects, exposure to infections as measured by parental reports obtained at age 10–14 years and by serological tests obtained in adulthood did not influence the development of wheezing symptoms or atopic status in adulthood. However, early exposure to measles and family size may be associated with a lower risk of adult onset doctor diagnosed asthma.
Footnotes
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Members of the Aberdeen WHEASE Study Group: K Brown, J G Douglas, J A R Friend, J S Legge, J Little, A Seaton
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Conflicts of interest: None
