Readers of a certain age may recall the use of diets in the management of peptic ulcer disease, their replacement by the introduction of increasingly complicated surgery such as highly selective vagotomy, and the subsequent discovery of the critical role of Helicobacter pylori infection in the causation of this (and other) diseases. What will the denouement for asthma be in 5, 10 or 15 years?

The output of the International Study of Asthma and Allergies in Childhood (ISAAC) over the last 14–15 years has told us a lot.1^–3 We now know that the prevalence of wheeze in the past 12 months amongst both 6- to 7-year-old and 13- to 14-year-old children varies only a little within countries but widely between countries. In the countries which have taken part in sequential phases of ISAAC, we know that in some the prevalence continues to rise, in others it has plateaued, whilst in others the number of affected children has fallen over a decade. The latest ISAAC report (see page 476) further contributes to this knowledge by informing us of data from a further 128 new centres.4 The results again demonstrate rates of current wheeze that, for example, vary from a third of New Zealand 13- to 14-year-old children having a current wheeze to <1% responding positively to this question in Tibet. Trends …