Prevalence of multiple sclerosis in north-east Scotland.

An epidemiological study of multiple sclerosis (MS) in north-east Scotland was carried out based on data correct on 1 December 1970. The prevalence of MS was 127 cases/100 000 population, which is greater than in any other surveyed area with a comparable population. The disease was not spread homogeneously within the region, and in one district one in 400 people was affected. The geographical distributions of MS and the presence of HLA antigens A3 and B7,which are associated with the disease, are remarkably similar, and the prevalence of B7 in north-east Scotland is higher than elsewhere. This may partly explain the high prevalence of MS in this area, but the essential additional environmental factor remains to be established.