1. The greater prevalence of persistent wheeze observed in the north and Wales is consistent with, although more marked than, the geographic variations in wheeze described in earlier reports.22 The proportionate annual increase between 1966 and 1990 in the prevalence of wheeze on most days or nights (1-9%) is rather smaller than the estimate of 5-2% provided by the National Study of Health and Growth between 1973 and 1986,12 although the 95% confidence limits on both estimates are wide. The annual increase is of a similar magnitude to that reported for wheeze in the past 12 months between 1978 and 1991 by Strachan and Anderson,1973
2. American Thoracic Society. Snowbird workshop on standardization of spirometry;AmRev RespirDis,1979
3. Respiratory morbidity and lung small.37 The striking increases in the prevalence of childhood cough and phlegm observed here function;Yarnell, J.W.G.; St Leger, A.S.,1981
4. Population Censuses and Surveys. General household survey 1988;Office of,19.)
5. Respiratory illness in British dioxide schoolchildren 1973-7. II: and atmospheric smoke Longitudinal findings;Melia, R.J.W.; du V, Florey C.; Chinn, S.