Have you seen the reports circulating that say: "... the most widely recommended treatments to reduce dust mites had no effect on the symptoms of asthma sufferers, researchers in Denmark found." MSNBC reported on this a few weeks back.
That's alarming, as it seems to go against what we've always heard about dust mites: reduce them, their waste and their carcasses and you will greatly reduce your allergies and asthma.
ABCNews.com reported on the same study and had this to say: "We sent the study to a panel of experts, and their response was that the study might show that dust mite control could make a difference if it is used as part of a larger program, including using air conditioning and keeping your windows closed, washing your hair and clothes at night and keeping pets indoors. Wrapping your mattress could also be helpful, but if that is your only effort to control dust mites it won't make much difference."
That is a more balanced statement (i.e. irritant reduction is part of a larger overall program, no one element solves any problem), but still I wondered "what is going on here? " Where did the researchers get their information since it seems to go against commonly held beliefs?
The Cochrane Collaboration Review
I read another dust mite related "study," which was not a direct study but a review conducted by Gøtzsche PC, Johansen HK, Schmidt LM, Burr ML of The Cochrane Collaboration. The mission of The Cochrane Collaboration: "Cochrane Reviews are based on the best available information about healthcare interventions. They explore the evidence for and against the effectiveness and appropriateness of treatments (medications, surgery, education, etc) in specific circumstances."
This review of 49 trials included a total of 2,733 patients from as far back as 1973. The review was first publishd in 2004 and republishd in 2007. This researchers conducting this review wrote, "We were unable to demonstrate any clinical beneﬁt to mite-sensitive asthmatics of measures designed to reduce mite exposure."
However they also state that: "Adherence to the applied measures was rarely evaluated...[and] that mite reduction was determined in different ways in the various studies. Some recorded mite counts and some measured antigen levels, using dust samples from different sources, and the reductions reported do not necessarily correspond to a similar reduction in the patients' exposure. For example,removing mites from the surface of mattresses and pillows does not affect the mite content of blankets or duvets, and merely killing the mites does not necessarily reduce airborne mite antigen, if nothing is done to remove the fecal particles that contain it. A potential reservoir for mites is the scalp, and it has been suggested that neglect of this source may explain the failure of many trials of mite eradication."
Three Weaknesses of the Review
But this review came under some fire of its own. The Allergy and Asthma Foundation of America issued a statement repudiating several of the Cochrane's conclusions. After reading the report, I have to agree with AAFA's statements.