To Örebro University

Background: Immunoglobulin E (IgE) sensitization is associated with asthma and allergic diseases. Gestational age influences early immune system development, thereby potentially affecting the process of tolerance induction to allergens. We aimed to study IgE sensitization to common allergens by gestational age from childhood up to early adulthood.  

Method: Population-based birth cohort, data from the Swedish BAMSE study was used. Allergen-specific IgE to a mix of common food (fx5) and inhalant (Phadiatop) allergens were analysed at 4, 8, 16 and 24 years. Sensitization was defined as allergen-specific IgE ≥0.35 kU A /l to fx5 and/or Phadiatop at each time-point. Using logistic regression and generalized estimated equations, adjusted odds ratios (aORs) for sensitization in relation to gestational age were calculated. Replication was sought within the Swedish twin study STOPPA.

Results: In BAMSE, 3523 participants were screened for IgE anti-bodies during follow-up; of these, 197 (5.6%) were born preterm (<37 gestational weeks), and 330 (9.4%) post-term (≥42 weeks). Preterm birth was inversely associated with sensitization to common food and/or inhalant allergens up to early adulthood; overall aOR = 0.71 (95% CI = 0.51- 0.98). An inverse association was also observed between preterm birth and sensitization to food allergens specifically; overall aOR = 0.59 (95% CI = 0.38- 0.95). No relation was found between post-term birth and IgE sensitization at any time-point. Replication analyses in STOPPA ( N  = 675) showed similar risk estimates for sensitization to food and/or inhalant allergens (aOR = 0.76; 95% CI: 0.45- 1.26), which resulted in a combined meta-analysis aOR = 0.72 (95% CI: 0.55- 0.95).  

Conclusion: Our study suggests an inverse association between preterm birth and later IgE sensitization.