Sociogeographic factors and multiple sclerosis--an ecological study in 6 European countries.

The pattern of the multiple sclerosis (MS) risk in Norway, Denmark, Sweden, Switzerland, Finland and Holland, as reported in previous studies, was compared with the distribution of several sociogeographic factors. For none of the variables tested did an association with MS exist in all of these countries. A correlation in more than one country was found for the proportion of industrial workers in the total population and for the extent of oat cultivation. Arguments against a causal role of these factors as such exist, however, and are discussed. For a number of other variables that might be implicated in the context of prior findings or suggestions either no or only an inconsistent association with MS was found.