A study of leukaemia in Glasgow in connection with chromium-contaminated land

Background In 1991, soil pollution was found around the site of a former ch romium-processing factory in Glasgow, Scotland. Levels of chromium in soil were above limits considered as safe, although a risk assessment concluded that population exposure was likely to be below occupational levels. As an excess incidence of leukaemia has been suspected in the area, it was decide d to investigate a possible relationship between the pollutant and the illn ess. Methods The ensuing study was descriptive-geographical, In the absence of b etter data, levels of exposure were assumed to decrease with distance from the centre of the polluted area. Leukaemia and population figures were obta ined for each of nine concentric rings by aggregation of data available at the Enumeration District level, The null study hypothesis was that relative risk (as measured by Poisson regression) would not follow a definite trend with distance from the centre. Sex, age and levels of deprivation were tak en into account. Results Relative risks by variables other than distance followed previously known patterns for leukaemia. No evident pattern by distance was found, Af ter regroupings inside the variables, a significant excess of leukaemia was found for intermediate distances from the pollutant. Conclusions No evidence was found of a possible relationship between soil p ollution by chromium and leukaemia in the general population. Nonetheless, the excess noticed by the study warrants further research.