GEOGRAPHIC SIMILARITIES BETWEEN VARICELLA AND MULTIPLE-SCLEROSIS - ANHYPOTHESIS ON THE ENVIRONMENTAL-FACTOR OF MULTIPLE-SCLEROSIS

The environmental factor causing multiple sclerosis (MS) is unknown. K urtzke et al. (Neurology 1979; 29: 1228-1235) depicted a north to sout h diminishing gradient in the case/control ratios for MS among America n veterans in the United States. A similar, but less precise, gradient emerged when the incidence rates of varicella from 37 states during 1 978-91 were compared. A loose correlation appears to exist between the mean incidence of varicella and the MS risk ratio (n = 0.344 Spearman rank correlation coefficient, p = 0.037). Further, the data on the fa te of migrants moving from a high risk MS country to a low risk countr y and the reverse, plus the great importance of the age at migration, raise the question of a possible connection between the two diseases. Because of these epidemiological and other similarities between the tw o diseases a further comparative study was suggested.