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Infections in early childhood and risk of atopic disease

J Pekkanen1, S Remes, M Kajosaari

  • 1Unit of Environmental Epidemiology, National Public Health Institute, Kuopio, Finland. Juha.Pekkanen@ktl.fi

Acta Paediatrica (Oslo, Norway : 1992)
|August 14, 1999
PubMed

Insights

Having fewer siblings increases the risk of developing atopic diseases like hay fever and eczema. Early childhood daycare attendance did not reduce this risk and may slightly increase hay fever symptoms.

Area of Science:

  • Epidemiology
  • Allergology
  • Pediatrics

Background:

  • A larger number of siblings is linked to a reduced risk of atopic diseases.
  • This protective effect is hypothesized to be due to increased infection exposure in larger families.
  • Children in daycare centers experience more respiratory infections, prompting investigation into this factor.

Purpose of the Study:

  • To analyze the association between the number of siblings and daycare attendance in early childhood (ages 1-3) with atopic disease risk.
  • To examine the relationship between sibling number and lifetime history or current symptoms of atopic diseases in adolescents.
  • To investigate if early childhood respiratory infections mediate the sibling-atopy association.

Main Methods:

  • Cross-sectional survey of 8387 schoolchildren aged 13-14 years and their parents in Finland.
  • Data collected on the number of siblings, daycare attendance (ages 1-3), and history of atopic diseases (hay fever, eczema, asthma).
  • Statistical analysis using odds ratios (OR) and 95% confidence intervals (CI) to assess associations.

Main Results:

  • Having no siblings was significantly associated with a higher risk of lifetime hay fever (OR 1.53) and atopic eczema (OR 1.28).
  • A trend towards increased risk of doctor-diagnosed asthma was observed for children with no siblings (OR 1.26).
  • Daycare attendance was not associated with reduced atopic disease risk; instead, it showed a slight increase in current hay fever symptoms (OR 1.34).

Conclusions:

  • The findings suggest that factors other than early childhood respiratory infections explain the link between sibling number and atopic disease risk.
  • The protective effect of having more siblings against atopic diseases may not be solely mediated by infection exposure.
  • Further research is needed to elucidate the complex interplay of genetic and environmental factors influencing atopic disease development.

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