Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma (Review)

Background

Dampness and mould in buildings have been associated with adverse respiratory symptoms, asthma and respiratory infections of inhabitants. Moisture damage is a very common problem in private houses, workplaces and public buildings such as schools.

Objectives

To determine the effectiveness of remediating buildings damaged by dampness and mould in order to reduce or prevent respiratory tract symptoms, infections and symptoms of asthma.

Search methods

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 2), which contains the Cochrane Acute Respiratory Infections Group's Specialised Register, MEDLINE (1951 to June week 1, 2011), EMBASE (1974 to June 2011), CINAHL (1982 to June 2011), Science Citation Index (1973 to June 2011), Biosis Previews (1989 to June 2011), NIOSHTIC (1930 to November 2010) and CISDOC (1974 to November 2010).

Selection criteria

Randomised controlled trials (RCTs), cluster-RCTs (cRCTs), interrupted time series studies and controlled before-after (CBA) studies of the effects of remediating dampness and mould in a building on respiratory symptoms, infections and asthma.

Data collection and analysis

Two authors independently extracted data and assessed the risk of bias in the included studies.

Main results

We included eight studies (6538 participants); two RCTs (294 participants), one cRCT (4407 participants) and five CBA studies (1837 participants). The interventions varied from thorough renovation to cleaning only. We found moderate-quality evidence in adults that repairing houses decreased asthma-related symptoms (among others, wheezing (odds ratio (OR) 0.64; 95% confidence interval (CI) 0.55 to 0.75) and respiratory infections (among others, rhinitis (OR 0.57; 95% CI 0.49 to 0.66)). For children, we found moderate-quality evidence that the number of acute care visits (among others mean difference (MD) -0.45; 95% CI -0.76 to -0.14)) decreased in the group receiving thorough remediation.

One CBA study showed very low-quality evidence that after repairing a mould-damaged office building, asthma-related and other respiratory symptoms decreased. For children and staff in schools, there was very low-quality evidence that asthma-related and other respiratory symptoms in mould-damaged schools were similar to those of children and staff in non-damaged schools, both before and after intervention. For children, respiratory infections might have decreased after the intervention.

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 or children, 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.

Plain Language Summary

Interventions for preventing or reducing symptoms of asthma, other respiratory symptoms and respiratory infections in mould-damaged buildings

Moisture damage is a very common problem in private houses, workplaces and public buildings around the world and has been associated with adverse respiratory symptoms, asthma and respiratory infections of inhabitants. Our aim was to determine the effectiveness of remediating buildings damaged by dampness and mould in reducing or preventing the occurrence of respiratory tract symptoms, infections and symptoms of asthma.

We included eight studies with 6538 participants; three randomised controlled trials (RCTs) and five non-RCTs. The interventions aimed to remove mould and dampness from family houses, schools or, in one study, an office building. When remediation of houses was compared to no intervention at all, we found evidence that mould remediation reduced asthma-related symptoms and respiratory infections. It also decreased the use of asthma medication in asthmatics. We found very low-quality evidence that after repairing a mould-damaged office that asthma-related and other respiratory symptoms decreased.

For extensive remediation compared with information only, there was moderate-quality evidence that the number of asthma symptom days among asthmatic children did not decrease significantly. However, the number of emergency and inpatient visits decreased after the repair of the building. Pupil visits to physicians due to a common cold were less frequent after the building was repaired but respiratory symptoms (stuffy nose, runny nose, dry throat, hoarseness, eye irritation) were similar before and after the intervention both among pupils and adults working in the schools. Due to a wide range of outcome measures and variation in study designs, it was difficult to draw hard conclusions. Better research is needed, preferably with a cluster-RCT (cRCT) design and with more validated outcome measures.