Source: Neuron  |  Posted 9 years ago

Intensive follow-up failed to find a relationship between exposure to house-dust mite (HDM) allergens in bedrooms of infants and the development of bronchial hyper-responsiveness at age six or seven years, researchers in the United States report.

Levels of HDM allergens were also not related to the infants developing doctor-diagnosed asthma at age 6 or 7 years.

Investigators from the Henry Ford Healthcare System in Detroit, Michigan, followed a cohort of 97 middleclass, suburban children born between 1987 and 1989, who were enrolled in the Childhood Allergy Study. The children had high cord blood immunoglobin E levels.

For the first two years of the children's lives, bedroom dust samples were collected monthly and analysed for Der f 1 and Der p 1. When the children reached age 6 or 7 years, 64 underwent clinical examination, skin-prick testing and methacholine inhalation challenge. A questionnaire was used to determine which children had doctor-diagnosed asthma.

Mann-Whitney testing compared Der f 1 and Der p 1 levels in the homes of children with/without bronchial hyper-responsiveness as well as those with or without asthma.

A total of 1,421 dust samples were collected and analysed. No significant differences were found in mean, maximum or minimum HDM allergen levels in homes of children with/without bronchial hyper-responsiveness or with/without asthma.

The researchers found HDM sensitisation was associated with doctor-diagnosed asthma, however.