A Cardiff University study has found that removing indoor mold improves the symptoms of people with asthma.

According to an organization named Asthma UK (a charity dedicated to improving the health and well-being of the 5.2 million people in the UK whose lives are affected by asthma), the prevalence of asthma in Wales is among the highest in the world, with 260,000 people receiving treatment for their asthma with the rate of hospital admissions for adults 12% more than anywhere else in the UK.

Researchers in the Cardiff University’s School of Medicine asked patients with asthma living in two areas of South Wales if they noticed mold growing inside their houses, which was then confirmed by a trained observer. In half of the houses with mold (chosen at random), the mold was removed (using a fungicidal wash to kill any remaining mould) and ventilation was improved by means of a fan in the loft. In the other houses, mold removal was delayed for 12 months.

Dr Michael Burr, the School of Medicine's department of primary care and public health, said: "In the houses where mold was removed, the symptoms of asthma improved and the use of inhalers decreased more than in the other houses. Removing mold also led to improvements in other symptoms: sneezing, runny or blocked noses, and itchy, watery eyes.

"There was no clear effect on measurements of breathing, but this may have been because patients used their inhalers as needed so that they could always breathe freely."

Jenny Versnel, Asthma UK's executive director of research and policy, said: "The publication of this study adds to the increasing bank of research that indoor mold may have a link with asthma, however, more work is needed in this area before definitive conclusions can be drawn.

"Research into this area does, however, highlight the importance of keeping your house dry and well ventilated. This can reduce exposure to certain asthma triggers such as mold spores which are found in damp places."

The study was funded by the charity Asthma UK, the Medical Research Council, and the Wales Office of Research and Development. The research is published in the September edition of the medical journal Thorax.  

Note: This story has been adapted from a news release issued by Cardiff University.