Prevalence and Natural History of Lung Disease in New South Wales Schoolchildren

Abstract

A five-year longitudinal survey of the interactive effects of lower respiratory tract illness and of social and environmental factors on the lung function of 12,000 schoolchildren, has been established. Lung function is assessed with the maximum expiratory flow-volume (MEFV) curve which provides values for peak expiratory flow, timed expiratory volumes and vital capacity. Flow rates during the latter half of forced expiration are measured from the MEFV curve as indices of function of the smaller airways. Computation methods have been developed to automate data collection, analysis and file construction. Lung function values from normal children compare closely with published data from other children of European origin. Children with a history of lower respiratory illness tend to have slightly, but significantly, lower values for some measurements of lung function than children without such a history. The prevalence of a history of treated asthma, bronchitis alone, and bronchitis with asthma was similar to that found in other populations of children studied in Australia. Although an apparent decline was found in smoking prevalence among the children aged 12 to 13 years in the first year of the survey (compared with a similarly aged group in 1968), a reversal of this effect was found in the same children one year later, in that they were smoking more than a similarly aged cohort in 1968. The effect of smoking on lung function and on prevalence rates for respiratory illness is being observed longitudinally with any statistically significant effect on lung function in a small group of 12 to 13-year-old boys.