Damp and mould-infested houses could be the cause of permanent asthma in children, researchers said. Poor housing conditions are already linked to the illness but there is debate whether they cause asthma, or simply trigger attacks, a private TV reported.
Finnish researchers writing in the European Respiratory Journal say they have proved this after surveying the homes of more than 300 children. However, UK asthma experts are still not convinced mould can cause asthma.
Damp in the home does more than merely exacerbate existing asthma - it can contribute to the onset of persistent asthma Dr Juha Pekkanen National Public Health Institute said. Asthma is now the most common chronic disease of school-age children, and rates have risen steadily in recent years in industrialised countries.
Dr Juha Pekkanen, from the National Public Health Institute in Kuopio, suggests that as many as one in five cases of child asthma may be caused by moisture and mould in the home. His team found that the severity of asthma increased alongside the severity of the damp in living areas. In all, the homes of 121 asthmatic children were compared to those of 241 non-asthmatic children. Evidence of serious damp or visible mould was seen two to three times more often in homes inhabited by asthmatic children. Mould and damp in non-family parts of the house, however, was not linked to the illness.
The researchers said this was clear evidence that mould and damp caused asthma in children, as opposed to worsening or triggering attacks in children whose asthma had another underlying cause.
It is not possible to distinguish conclusively between the role of moisture damage and mould as a trigger factors and any causal link with childhood asthma based on the current evidence.
POLLUTION MAY BOOST ASTHMA RISK:
Traffic pollution may boost the risk of children getting asthma - if they have genes which make them vulnerable, a study says. The University of Southern California team studied the health records and genetic profiles of 3,000 children. Those with a gene variation were slightly more at risk but if they lived near a main road, the risk rose more, the Thorax journal reported.
But UK asthma experts said the link remained unclear. Scientists exploring how respiratory diseases, including asthma, develop have highlighted the importance of genes which control key body chemicals linked to "clean-up" functions in the body.
Enzymes called EPHX1 and a gene called GSTP1 appear to have some responsibility for getting rid of harmful chemicals, which we breathe in. The researchers found that those who had high levels of EPHX1 were 1.5 times as likely to have been diagnosed with asthma, while those who also had variations in GSTP1 as well were four times as likely to have asthma. However, living close to a main road appeared to make this effect even greater.
This study is very promising as it is one of the first to look specifically at how genetic susceptibility to respiratory disease and environmental traffic fumes can cause childhood asthma. Children with very active EPHX1 who lived within 75 metres of a road had a doubled risk of asthma compared with those who had low EPHX1 levels.
Having active EPHX1, variations in the gene, and a home near a road meant a risk nine times greater. Their conclusion was that while children with the wrong genes and enzyme activity were more prone to having asthma, living near a road seemed to compound that risk.