Epidemiological studies on multiple myeloma

Sammanfattning: Multiple myeloma is a painful and uncurable malignant disease with an increasing incidence and mortality in several countries, e.g., Sweden. Some factors are suspected to be of aetiological significance, such as ionising radiation and chronic antigenic stimulation in certain inflammatory diseases. A familial factor has also been indicated. Furthermore, some studies have demonstrated farming as an occupation entailing an increased risk for the disease.The aim of this investigation was to further elucidate the impact of different aetiological factors in relation to multiple myeloma. The knowledge of aetiology is always a prerequisite for prevention.A case-control study on multiple myeloma was performed in a high-inddence area, the northern part of Sweden. One part of this study dealt with occupations and different exposures. The results supported farming as being an occupation with an increased risk. Within farming two kinds of pesticides, phenoxyacetic adds and DDT, and contact with certain domestic animals, i.e., cattle, horses and goats, were assodated with multiple myeloma.Farming as a risk factor was also confirmed by a register-based linkage study using the Swedish Cancer Environment Register. In this study a time trend was indicated, with increasing standardized inddence ratios over the different time periods studied.Another part of the case-control study showed that rheumatoid arthritis entailed an increased risk for multiple myeloma, a finding earlier suggested from register-based linkage studies, but not from any çase-control study.A third part of the case-control study indicated an increased risk for multiple myeloma if any first-degree relative had a history of haematological malignancy, or other malignant tumour, espedally prostatic cancer, brain tumour, and renal cancer.A case study encompassing 942 patients with haematological malignandes in the county of Jämtland, Sweden, during a 22-year period showed that about 5% of the patients had at least one relative who also suffered from such a disease. An espedally strong familial occurrence was found in the group of chronic lymphoprohferative diseases, including multiple myeloma.