Prevalence of asthma among 12 year old children in New Zealand and South Wales: a comparative survey.

A survey of 12 year old schoolchildren was carried out in New Zealand and South Wales, the same questionnaire and exercise provocation test being used. The prevalence of a history of asthma at any time was higher in New Zealand (147/873, 17%) than in South Wales (116/965, 12%). The New Zealand children were also more likely than the Welsh children to have a history of "wheeze ever" (27% versus 22%), and wheeze brought on by running (15% versus 10.5%). The sex ratio of asthmatic and wheezy children was very similar in the two countries. A history of hospital admission for chest trouble was twice as common in New Zealand as in South Wales. An exercise test produced a fall in peak expiratory flow rate of 15% or more in more New Zealand children (12.2%) than Welsh children (7.7%). These results suggest that the prevalence of childhood asthma is higher in New Zealand than in South Wales.