Background
Moisture damage is a very common problem in private houses, workplaces and public buildings globally. It has been associated with asthma and respiratory symptoms of the inhabitants.
Study characteristics
We included 12 studies with 8028 participants. Three were randomised controlled trials (RCTs) and nine were non-RCTs with a control group. The repairs aimed to remove mould and dampness from family houses, schools or, in one study, an office building.
Key results
Repair of houses compared to no repair
Repairing houses to remove mould reduced asthma-related symptoms and respiratory infections compared to doing nothing. It also decreased the use of asthma medication in asthmatics. The repair of an office damaged by mould also reduced asthma and respiratory symptoms compared to an office that was not repaired. Full or partial repair did not result in a difference in symptoms. However, the evidence was of low to very low quality.
Repair of houses compared to information for the inhabitants
There was moderate-quality evidence that there was no clear benefit from repair of houses on asthma symptoms among asthmatic children.
Repair of schools compared to schools without problems
Out of many symptom measures only pupils' visits to physicians due to a common cold were less frequent after the building was repaired. For other respiratory symptoms of the pupils, the results were inconsistent.
For adults working in the schools, there was no clear evidence that the repair was beneficial.
Quality of evidence
The quality of evidence varied from very low to moderate quality. Many different symptoms were measured and studies were set up differently, therefore it was difficult to draw hard conclusions. Better research is needed, preferably with a cluster-randomised design and with better measurement of the symptoms.
Authors' conclusions:
We found moderate to very low-quality evidence that repairing mould-damaged houses and offices decreases asthma-related symptoms and respiratory infections compared to no intervention in adults. There is very low-quality evidence that although repairing schools did not significantly change respiratory symptoms in staff, pupils' visits to physicians due to a common cold were less frequent after remediation of the school. Better research, preferably with a cRCT design and with more validated outcome measures, is needed.