International variations and temporal trends in mortality from multiple myeloma.

Mortality statistics for multiple myeloma over the period 1960-1975 have been analysed for 23 countries. Attention has been focused on international variations, secular trends, and the male to female mortality ratio. The greatest percentage increases have been found in countries with low overall rates. The male:female ratio was generally higher in countries with high rates, and the national rates correlated more strongly with GNP per caput than with an index of medical care (hospital beds/10,000). Further analyses have been carried out over the period 1955-79 in Sweden, a country with high but relatively stable rates, and Japan, where the rates are very low but are increasing rapidly. An age, period, and cohort analysis of the trends in these countries is presented and criticized. The contributions made by increased diagnostic capability and by an increase in the true incidence of the disease are discussed.