House dust mite allergens. A major risk factor for childhood asthma in Australia.

TLDR

House dust mite allergen exposure is hypothesized to directly influence asthma severity. The study examined the relationship between house dust mite exposure and asthma in six large random samples of children across New South Wales. Researchers measured wheeze, airway hyperresponsiveness, and house dust mite sensitization via questionnaires, histamine inhalation tests, and skin prick tests, and quantified bedroom Der p I levels in about 80 children per region. Higher bedroom Der p I levels were linked to increased sensitization, airway hyperresponsiveness, and wheeze, with the risk of current asthma doubling for each two‑fold increase in exposure, indicating that reducing mite exposure could substantially lower childhood asthma.

Abstract

If house dust mite allergen (Der p I) is an important cause of asthma, there should be a direct relationship between level of exposure to this allergen and asthma severity. To examine this, we studied six large random samples of children in different regions of New South Wales, Australia. We measured recent wheeze by questionnaire, airway hyperresponsiveness (AHR) by histamine inhalation test and sensitization to house dust mites by skin prick tests. Current asthma was defined as the presence of recent wheeze and AHR. We measured Der p I levels in the beds of approximately 80 children in each region. In regions where Der p I levels were high, more children were sensitized to house dust mites, and these children had significantly more AHR and recent wheeze. After adjusting for sensitization to other allergens, we found that the risk of house dust mite-sensitized children having current asthma doubled with every doubling of Der p I level. There was a modest correlation between AHR and Der p I exposure in individuals (r = 0.23, p < 0.03). These data suggest that house dust mite allergens are an important cause of childhood asthma and that reducing exposure to these allergens could have a large public health benefit in terms of asthma prevention.