Patterns of childhood cancer by ethnic group in Bradford, UK 1974–1997

Abstract

The highly urbanised northern English city of Bradford contains a diverse population from different ethnic backgrounds, including a high proportion of south Asians. We aimed to identify the effect of ethnic group on the incidence and temporal trends of childhood cancer in Bradford. Children (0–14 years) from the district of Bradford, who were diagnosed with a malignancy between 1974 and 1997, were selected from a population-based register. Each child was classified as south Asian (Indian, Pakistani and Bangladeshi), or not, based on their full name using 2 computer algorithms and individual inspection. Mid-year population estimates were used to calculate incidence rates and differences were assessed using Poisson regression. The study included 318 children, of whom 81 (25%) were south Asian. The incidence of all cancers in south Asian children (14.9 per 100,000 person years, 95% CI 11.6–18.2) was higher than non-south Asian children (12.0, 10.5–13.5) although not significantly so ( P=0.14). Comparisons by diagnostic subgroup showed no major differences apart from significantly higher rates of acute myeloid leukaemia (AML) in south Asian children (1.9 versus 0.7, P=0.02). The age-specific incidence peaks of all childhood cancers and leukaemias were present in south Asian children aged 5–9 years compared with 0–4 years olds in the non-south Asian population. Non-significant increases of 1.4 and 1.5% in the average annual incidence of all cancers were seen for south Asians and non-south Asians respectively, with a significant rise for non-south Asians with leukaemia of 3.0% ( P=0.04). Our timely study shows patterns of occurrence of childhood cancer that differ with respect to ethnic group. Differences are particularly apparent in the excess of AML and incidence peak in 5–9 year olds in south Asian children.