Geography in multiple sclerosis.
In this paper, which is partly a review and partly based on original data, John Kurtzke lays out the big picture of multiple sclerosis epidemiology. He points out that the assertion of the day, that latitude determines multiple sclerosis prevalence, is incorrect. He notes that Scandinavia stands out as having a high prevalence of MS, which he interprets to suggest that it is “intrinsically related to geography” and thus “an acquired, exogenous, environmental disease.” To determine when the disease might be acquired, Kurtzke compares the age at which migration alters the risk of acquiring multiple sclerosis. He then presents new data on the risk of multiple sclerosis in veterans—by race and gender—and shows that it is greatest in white women. Kurtzke argues that if multiple sclerosis is due to an infectious agent rather than a toxin, transmissibility should be evident. He is keen to discuss possible “epidemics” of multiple sclerosis, based on his travels to the Faroe Islands, where a cluster of new cases seemed to follow the stationing of British troops. Kurtzke’s interpretation of the Faroese epidemic of multiple sclerosis has been the most controversial aspect of his work. But that should not detract from the enormous service he has performed in marshalling the huge and complex multiple sclerosis epidemiological data set into digestible synopses, of which this paper is a prime example.