Elsevier

The Lancet

Volume 356, Issue 9239, 21 October 2000, Pages 1392-1397
The Lancet

Articles
Early exposure to house-dust mite and cat allergens and development of childhood asthma: a cohort study

https://doi.org/10.1016/S0140-6736(00)02842-7Get rights and content

Summary

Background

In a prospective birth-cohort study, we assessed the relevance of mite and cat allergen exposure for the development of childhood asthma up to age 7 years.

Methods

Of 1314 newborn infants enrolled in five German cities in 1990, follow-up data at age 7 years were available for 939 children. Assessments included repeated measurement of specific IgE to food and inhalant allergens, measurement of indoor allergen exposure at 6 months, 18 months, and 3 years of age, and yearly interviews by a paediatrician. At age 7 years, pulmonary function was tested and bronchial hyper-responsiveness was measured in 645 children.

Findings

At age 7, the prevalence of wheezing in the past 12 months was 10·0% (94 of 938), and 6·1% (57 of 939) parents reported a doctor's diagnosis of asthma in their children. Sensitisation to indoor allergens was associated with asthma, wheeze, and increased bronchial responsiveness. However, no relation between early indoor allergen exposure and the prevalence of asthma, wheeze, and bronchial hyper-responsiveness was seen.

Interpretation

Our data do not support the hypothesis that exposure to environmental allergens causes asthma in childhood, but rather that the induction of specific IgE responses and the development of childhood asthma are determined by independent factors.

Introduction

Epidemiological surveys indicate that there has been a notable increase in the prevalence of both asthma and other allergic symptoms in children and young adults.1, 2 Since it seems unlikely that genetic factors contribute to this rising trend, environmental factors might play a major part in the development of childhood asthma. Several potential determinants have been proposed, such as lack of severe or repeated infections,3, 4 obesity and lack of physical exercise,5 decreased family size,6 changing dietary habits,7, 8 and increase of indoor allergen exposure.9

There is some evidence that the level of indoor allergen exposure is related to an individual's capacity to mount specific IgE responses towards these allergens.10, 11, 12 Some recently published cross-sectional studies assessing cat exposure retrospectively failed to detect a positive association.13, 14 However, the extent to which the inception of childhood asthma is also determined by the level of indoor allergen exposure remains unclear.15, 16 Epidemiological surveys of children raised in environments with very low exposure to dust-mite allergen indicate that the prevalence of asthma is not decreased compared with children in mite-infested areas.17, 18

We prospectively investigated the relation between indoor allergen exposure and the development of asthma in a large cohort of German children up to age 7 years.

Section snippets

Study design

In the German Multicentre Allergy Study, 7609 newborn infants were recruited in five German cities (Berlin, Düsseldorf, Freiburg, Mainz, and Munich) during 1990. Of these 7609 children, 1314 were selected for the prospective study. 499 infants (38%) were included as being at high risk of developing asthma (having at least two atopic first-degree family members or raised cord-blood IgE >0·9 kU/L). 815 infants (62%) were chosen at random from the remaining newborn infants (one or no atopic family

Results

At age 7 years, 939 children presented for check-up Complete data from questionnaires, indoor allergen exposure, and specific sensitisation were available for 648 children (table 1). To assess potential participation bias, participating children were compared with all other children in the Multicentre Allergy Study birth cohort, on the basis of data collected at birth (for pet ownership and indoor allergen exposure data based on the first 3 years of life). The study population (648 children)

Discussion

In this large prospective study, the development of childhood asthma was not related to cat and mite allergen exposure in the first years of life or to cat ownership, although sensitisation to mite and cat allergens was associated with indoor allergen exposure, as reported previously.10, 11, 12 The association between allergic sensitisation to indoor allergens and the prevalence of bronchial hyper-responsiveness and asthma, which has been shown in cross-sectional studies,22, 23, 24 was

References (34)

  • ML Burr et al.

    Changes in asthma prevalence: two surveys 15 years apart

    Arch Dis Child

    (1989)
  • J Yunginger et al.

    A community-based study of the epidemiology of asthma. Incidence rates. 1964 1983

    Am Rev Respir Dis

    (1992)
  • T Shirakawa et al.

    The inverse association between tuberculin responses and atopic disorders

    Science

    (1997)
  • SO Shaheen

    Obesity and asthma

    Clin Exp Allergy

    (1999)
  • E Von Mutius et al.

    Thieman H-H. Skin test reactivity and number of siblings

    BMJ

    (1994)
  • K Demissie et al.

    Usual dietary sodium intake and asthma in children: a case-control study

    Thorax

    (1996)
  • L Hodge et al.

    Effect of dietary intake of omega-3 fatty acids and omega-6 fatty acids on severity of asthma in children

    Eur Respir J

    (1997)
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