Variations in cancer mortality among local authority areas in England and Wales: relations with environmental factors and search for causes.

Geographical variations in specific causes of mortality among the 1366 local authority areas of England and Wales as defined at 1971 were studied by examining extracts from death certificates held on computer tape. Five items of information on each death--year of death, age at death, sex, local authority area of residence, and the underlying cause of death, during the 11 years 1968-78--permitted a more detailed investigation than had been possible before. Analysis of some early results of the study--including maps of mortality for pleural mesothelioma, nasal cancer and bladder cancer--suggested that, despite the known limitations of death certification, systematic study of the mortality of small areas may give clues to aetiological factors in the environment. Analyses relating mortality to the distribution of environmental factors and examining disease profiles of each area may also provide clues. These will be followed up by other methods of study, such as case-control techniques.