Analysis of incidence of childhood cancer in the West Midlands of the United Kingdom in relation to proximity to main roads and petrol stations

Objectives-To investigate whether there is an excess of leukaemias in 0-15 year old children among those living in close proximity (within 100 m) of a main road or petrol station. Methods-Data for 0-15 year old children diagnosed between 1990 and 1994 in the United Kingdom West Midlands were used. Postcode addresses were used to locate the point of residence which was compared with proximity to main ro ads and petrol stations separately, and to both together. Odds ratios (ORs) were calculated with solid tumours as a control, and incidence ratios (IRs ) with population density as a control. Results-The method based on solid tumours as a control showed ORs of 1.61 ( 95% confidence interval (95% CI) 0.90 to 2.87) and 1.99 (95% CI 0.73 to 5.4 3), for those living within 100 m of a main road or petrol station respecti vely. When population was used as a control, the estimated IRs for leukaemi a were 1.16 (95% CI 0.74 to 1.72) and 1.48 (95% CI 0.65 to 2.93) for reside nce within 100 m of a main road or petrol station respectively, but neither reached significance at the 95% level. Results for residence in close prox imity to bath a main road and petrol station were inconsistent, but there w ere few. The influence of socioeconomic factors as represented by the Towns end deprivation index on leukaemia incidence was not significant and the re sults were not explicable on the basis of impact of social class. Conclusions-The results are suggestive of a small increase in risk of child hood leukaemia, but not solid tumours, for those living in close proximity to a main road or petrol station. This increase in risk is not, however, si gnificant and a larger study is warranted to establish the true risk and ca uses of any increase in risk.