Figure 4:
Annual change in hospital admission rates for childhood asthma (ages 5-14) by change in prevalence of nocturnal wheezing among 13-14-year-olds in countries with one or more ISAAC centres providing prevalence data for both ISAAC Phase One (around 1995) and ISAAC Phase Three (around 2002).

Sources: National admissions data from Anderson HR et al. IJE 2008; (updated by WHO Hospital Morbidity Database). Prevalence data fom Pearce NE et al. Thorax 2007.

Average annual change in asthma admission rate aged 5-14 (per 10,000)
Average annual change in nocturnal wheeze prevalence (per 100,000 children)