Multiple myeloma in south Cumbria: prediction fulfilled.

In 1985 a paper in this journal analysed an apparent cluster of multiple myeloma in South Cumbria, England. The study was prompted by reports of seven cases of multiple myeloma in Walney Island. This is a small community adjacent to a shipyard that builds nuclear submarines and is 15 miles away from the Sellafield Nuclear Processing Plant. These seven cases occurred over the seven year time period 1974–1980, during which only 2.8 cases would have been expected on Poisson assumptions (p = 0.02). Because of the problems of post hoc cluster definition, we studied the incidence of multiple myeloma across the health district of South Cumbria. Using a casecontrol method no excess of known or possible risk factors were found to account for this high incidence and we concluded that “the most likely explanation is that this was a random occurrence which will not persist or recur”. We now present data that test this explanation.