Trends in the incidence of multiple myeloma in Denmark 1943-1982: a study of 5500 patients.

The incidence of multiple myeloma in Denmark during the period 1943-82 was examined, based on the files of the Danish National Cancer Registry. A total of 5535 patients (3023 male and 2512 female) were registered. Over the period 1943-62 the incidence increased 2- to 3-fold for both men and women, but the increase in men was steeper and was seen several years before the increase in women in all 5-yr age groups from 50 to 75 yr of age. This pattern would be compatible with an impact of environmental factors. The increase, also percentagewise, rose with increasing age. Since 1963 the incidence has been virtually stable with a possibly decreasing trend during the latest 5- to 10-yr period.