Congenital anomalies in Glasgow between 1982 and 1989 and chromium waste

Background The former site of a factory in Glasgow and nearby areas were found to be heavily polluted by chromium waste. This gave rise to local concern on possible health effects. As part of a wider study answering this concern, congenital malformations were investigated. Methods A descriptive geographical study was carried out. A 10 km circle centred on the factory site was designated as the study area and subdivided into one circle of 2 km radius and eight 1 km wide rings. Significant differences in relative risk between the circle and rings and a decreasing trend of risk with distance from the centre would point towards a teratogenic role of the chromium waste. Relative risks by rings were obtained by Poisson regression. Relative risks by deprivation categories were also obtained, with most results adjusted by these categories. Results Significant differences in risk appeared, with the area containing the polluted soil having the lowest risk. Aggregations of rings showed a central area with a relatively low risk, followed by an intermediate one with the highest risk and an external area with risk also high. Relative risk appeared to increase sharply between the most affluent category and the rest, then growing steadily with increasing deprivation but decreasing slightly for the most deprived. Conclusions Relative risk shows a significant peak in an area 2-4 km away from the pollutant, which does not point towards a possible teratogenic effect of the chromium waste. Relative risk of congenital malformations for the more affluent sector of the population appeared to be markedly lower than that for the rest.