Dr. Helen McAvoy:

It is very difficult to give a proportion on that because we do not have a longitudinal study following the same children over time in Ireland. We have a longitudinal study but, unfortunately, it does not include data on e-cigarette to tobacco use. Longitudinal studies are where the same group of children is followed over a period of time. Those types of studies provide a higher level of evidence than taking a different sample of children every few years and are more supportive of a relationship between e-cigarette use and subsequently using tobacco. I do not have any figures on that but we can come certainly back to the Deputy with the findings from some those of longitudinal studies, which would give him an estimate of the strength of that association.