Mouse allergen in US homes linked to asthma.
Salo, PM, R Jaramillo, RD Cohn, SJ London and DC Zeldin. Exposure to mouse allergens in US homes associated with asthma symptoms. Environmental Health Perspectives doi:10.1289/ehp.11847.
This is the first study to determine an association between asthma and mouse allergens in US residential homes.
Previous studies have found a similar link for people at work and those living in urban settings, where the population may have a generally high risk/prevalence of asthma. It was unknown whether the same association existed in households outside of inner city areas.
A team of researchers measured concentration of mouse urinary protein in 831 homes (total of almost 2,500 people) in 75 locations across the US. Of the surveyed homes, the majority (85%) had detectable concentrations of mouse allergen (highest level in the kitchen, lowest in living room and bedroom). Mouse allergen at levels higher than amounts sufficient to induce asthmatic symptoms was detected in approximately 35% of these exposed houses.
The study found that individuals living in homes with higher levels of mouse allergen reported more asthmatic symptoms in the past 12 months. The authors conclude that: "In allergic asthma, residential mouse allergen exposure is an important risk factor for asthma morbidity."
These data do not address why asthma has increased in the United States so dramatically over the past two decades. There is no reason to assume that mice or mouse allergens have become more common.