Geographical variations and recent trends in cancer mortality in Northern Ireland (1979-88).

Cancer mortality in the 35-74 year age-range for selected sites during the period 1979-88 was investigated for the 26 district council areas of Northern Ireland. Trends in rates during the period were also studied and compared with trends in an earlier period, and with trends reported from the rest of the United Kingdom. Statistically significant differences between the age-standardised death rates in the 26 areas were observed for stomach cancer (women only), pancreatic cancer (women only), lung cancer (men and women) and for all cancers (men and women). Some evidence of spatial aggregation of rates was apparent for ovarian cancer even though rates in the 26 areas did not differ significantly. The patterns are illustrated with maps and some difficulties of interpretation are discussed. Mortality rates for oesophageal cancer increased during the period in both sexes while rates for stomach cancer decreased. Colon cancer rates increased significantly only in men, while an increase in lung cancer rates was confined to women. The mortality from all cancers increased significantly during the period by 0.8% per annum in men and 0.9% per annum in women. These trends were found to be broadly comparable with those reported elsewhere in the United Kingdom.