House dust mite control measures for asthma

As Cochrane reviews are updated, more studies are often added, providing more reliable evidence of the effects, or not, of treatments. This is true for a Cochrane review of strategies to reduce the harmful effects of house dust mites on people with asthma. We asked Peter Gotzsche to tell us more about the work he has done with Helle Johansen at the Nordic Cochrane Centre in Copenhagen.