Respiratory health of children living on the island of Montserrat

In July 1995 the volcano on the Caribbean island of Montserrat started to erupt. Since then it has been intermittently generating clouds of ash, mostly made up of small, respirable particles containing crystalline silica. Even between heavy ashfalls, there are peaks in the concentration of suspended ash associated with both indoor and outdoor activity but which are invisible. Montserratians may be at risk of silicosis and other respiratory diseases. Our study aimed to evaluate whether the ash has had any effect on respiratory symptoms and bronchial responsiveness in children living in Montserrat. The International Study of Asthma and Allergies in Childhood questionnaire was administered to children aged 13 and over and to the parents of children aged 12 and under. Additional information was collected about place of residence since the eruption started. Each place of residence was independently assessed as high, moderate or low exposure to volcanic ash emissions. Exercise induced bronchial reactivity was measured in 8 to 12 year olds. The 140 children aged 8 to 12 years who had ever been exposed to moderate or high levels of volcanic ash emissions had a higher prevalence of wheeze in the last 12 months than the 83 children who had been exposed to low levels (odds ratio 4.3, 95% confidence intervals 1.7 to 10.9). In the older age group the size of the effect was in the same direction but smaller, and not significant, which may reflect the smaller sample size. The 19 children who were exposed to moderate to high levels of ashfalls at the time of the survey had a higher prevalence of exercise-induced bronchial hyperreactivity than those who were not (odds ratio 3.9, 95% confidence intervals 1.2 to 12.1). These findings suggest that exposure to volcanic ash is associated with more respiratory symptoms and more reactive airways in children and that there should be continued efforts to minimise exposure of children in Montserrat to ash emissions.