• allergens;
  • allergy;
  • asthma;
  • house dust mite;
  • intervention

To cite this article: Gehring U, de Jongste JC, Kerkhof M, Oldewening M, Postma D, van Strien RT, Wijga AH, Willers SM, Wolse A, Gerritsen J, Smit HA, Brunekreef B. The 8-year follow-up of the PIAMA intervention study assessing the effect of mite-impermeable mattress covers. Allergy 2012; 67: 248–256.


Background:  Exposure to high levels of house dust mite (HDM) allergens is associated with the development of allergic sensitization to HDM, a risk factor for the development of asthma, rhinitis, and allergic dermatitis. We studied the effect of an early intervention with mite-impermeable mattress covers on HDM allergen levels and the development of asthma and mite allergy throughout the first 8 years of life.

Methods:  High-risk children (allergic mother) were prenatally recruited and randomly allocated to two groups receiving mite allergen–impermeable (= 416) and placebo mattress covers (= 394) or no intervention (= 472). Asthma and allergies were assessed yearly by questionnaire. Specific immunoglobulin E and bronchial hyper-responsiveness were measured at the age of 8 years. Mattress dust samples collected at different time points were analyzed for HDM allergens.

Results:  At the age of 8 years, levels of HDM allergen Der f1 but not Der p1 were lower in the active than the placebo mattress cover group. In repeated measures analyses, we found a temporary decreased risk of asthma symptoms at the age of 2 years in the intervention group compared to the placebo group and a temporary association between higher HDM allergen exposure at the age of 3 months and more asthma symptoms.

Conclusion:  Early intervention with mite-impermeable mattress covers is successful in reducing exposure to Der f1; it only temporarily reduces the risk of asthma symptoms and does not reduce the risk of hay fever, eczema, and allergic sensitization.