Hospital admission patterns of childhood respiratory illness in Cape Town and their association with air pollution and meteorological factors
The aims of this study were (a) to examine the profile of hospital admissions for selected respiratory illnesses for two major hospitals in Cape Town, and (b) to analyse the association of such admissions with air pollution indicators and meteorological variables. The first part of the study investigated the admission patterns of coloured and African children under twelve years of age who were diagnosed as suffering from asthma or acute respiratory infections at two major teaching hospitals in Cape Town. Computerized hospital admission records covering the years 1988-1990 from the overnight holding wards of the Red Cross War Memorial Children's Hospital and Tygerberg Hospital were used to determine patterns with respect to diagnosis, gender, race, age and date of admission. During the three year study period, respiratory admissions at both hospitals accounted for 15 078 (47.3%) out of a total of 31 887 admissions. Acute respiratory infections accounted for 63.6% and asthma 37.4 % of these respiratory admissions. Two factors of interest were noted: (1) Considerably more males than females were admitted with both asthma and acute respiratory infections. (2) Asthma admissions to Red Cross Hospital among African children were proportionally much less than those of coloured children when compared to the proportions of admissions for acute respiratory infections. After removal of the seasonal effect, a multiple linear regression model was fitted to the data to determine the individual associations between admissions and ambient environmental variables. Significant associations were found between: (1) acute respiratory infections and oxides of nitrogen, soiling index, and temperature; (2) asthma and oxides of nitrogen (3) total admissions and soiling index, average temperature and minimum temperature (negative). The study concluded that despite generally low levels of air pollution in Cape Town, childhood respiratory admissions to Red Cross War Memorial Children's Hospital and Tygerberg Hospital were statistically significantly associated with some ambient air pollutants as well as temperature. However, given the nature of both the exposure and admissions databases, these results should be treated with caution. More representative site selections for air pollution monitors, as well as searching and controlling for possible confounding factors (i.e. indoor air pollution, parental smoking, overcrowding), would allow a better understanding of the current air pollution problem and the possible effects on the respiratory health of children in metropolitan Cape Town.
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Department of Environmental and Geographical Science