In September 2008 a paper was published by a group in New Zealand titled "Association between paracetamol use in infancy and childhood, and risk of asthma, rhinoconjunctivitis, and eczema in children 6-7 years: analysis from Phase Three of the ISAAC programme". The paper suggested that exposure to paracetamol might be a risk factor for the development of asthma in childhood.
However, this is a postal questionnaire study of parents with 6 to 7 year old children, asking them to remember what medicine they gave to their children 6 years earlier. As such it is very open to error. It is also likely that parents of children with asthma might better remember giving paracetamol in the first year of life, and parents of sick children might be more likely to use paracetamol, and to be aware of any minor symptoms such as wheeze. These are all confounding issues that make it difficult to gain any real knowledge from this study.
As with earlier studies, this study shows a statistical association that does not prove paracetamol use causes asthma. The authors' observations that greater paracetamol use currently in their children is associated with greater incidence of asthma and other symptoms in no way proves that paracetamol is causing the symptoms ; poorly children may well have more reason to be given paracetamol and as patients with asthma should not use ibuprofen products, children with asthma are given paracetamol when medication is needed.
We would welcome solid and robust studies that would put an end to this speculation about paracetamol use and asthma that simply causes worry and confusion for parents.
In the meantime there is no evidence for advising any change in the use of paracetamol.