Many children experience chesty coughs or wheezing during their first years of life, particularly when they have colds. Although most children outgrow these symptoms as they become older, some go on to develop asthma. Therefore, when toddlers have symptoms of wheeze or cough coming from the chest, their parents and doctors are often concerned that these may be the first signs of asthma. But how can one tell whether or not a child will in fact develop asthma?

About 10 years ago a cohort study in Tucson, USA, developed the Asthma Predictive Index, a rule for predicting which preschool children are at risk of developing asthma. Although many doctors have been using this rule, researchers had not actually tested how well the rule worked in different populations. Also, it was unclear which bits of information used in the rule - some of this information requiring blood samples to be taken from the children - are most important for good prediction and which bits might not be necessary.

Our team tested how well the Asthma Predictive Index predicted which of the children in the Leicestershire Cohort Studies developed asthma and compared results with more simple rules based only on the pattern of symptoms the children had in early life. We found that, although the Asthma Predictive Index worked as well in Leicester as it did in the American cohort, the simple rules worked almost as well.

These results, which have just been published (June 2011) suggest that the most useful information about whether or not a child will develop asthma is found in the pattern of symptoms they have in early life. Focusing on this information, which is easy to obtain and does not require blood samples, may lead to improved prediction rules. Our group is currently working on developing such rules.