Cancer incidence by Ethnic Group in England, 2001-2007
Background There are large unexplained variations in the incidence of many cancers globally and the incidence of cancer in migrant populations can contribute to our understanding of aetiology for cancers for which there are few established risk factors. Studying different ethnic groups in the same country overcomes the limitations of some international comparisons as similar diagnostic methods, reporting and registration procedures are used. The primary objective of this study is to compare the incidence of all major cancers in the six main ‘non-White’ ethnic groups in England to each other and to Whites using self-assigned ethnicity. A secondary objective is to compare these incidences with their countries of origin. Methods All cancer registrations from 2001–2007 in England were analysed. Ethnicity was obtained by linkage to the Hospital Episodes Statistics database and mid-year population estimates from 2001-2007 from the Office for National Statistics. Age-standardised incidence rates were calculated for all ethnic groups and incidence rate ratios (adjusted for age, sex and income) were calculated comparing the six non-White ethnic groups (and combined ‘South Asian’ and ‘Black’ groups) to Whites and to each other. Results There were significant differences in the incidence of nearly all cancers between the ethnic groups. In general, incidence was lower in non-White ethnic groups, but there was considerable variation with South Asians having higher rates of head & neck, liver, gallbladder, Hodgkin lymphoma and thyroid cancer and Blacks having higher rates of stomach, liver, gallbladder, prostate, endometrium, non-Hodgkin lymphoma, myeloma, thyroid and childhood cancers. There also was strong evidence of differences in risk between Indians, Pakistanis and Bangladeshis for most cancers and between Black Africans and Black Caribbeans for many. Conclusions The risk of most cancers varies greatly by individual ethnic group, including within those groups that have traditionally been grouped together (South Asians and Blacks). Many of these differences are not readily explained by known risk factors and suggest that important, potentially modifiable causes of these cancers are still to be discovered. In order to understand why these differences exist and the relative contribution of genetic and environmental factors, a large, prospective cohort study of non-White ethnic groups in the UK with individual level risk-factor information is needed.
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