Studies on the natural history of multiple sclerosis

Abstract

Comparisons were made between multiple sclerosis (MS) cases and MS controls, non-MS cases and non-MS controls, and MS cases and non-MS cases. Factors tested originated in data obtained routinely for cases and controls before MS was diagnosed in the Army. There is evidence that the cause or causes of MS will be found in certain environmental factors and that a genetic predisposition could assume significance only in association with some exogenous influence. The geographic differentiation was such that the highest risk of MS was in the northeastern part of the USA and the lowest in the Southwest. There was a preponderance of MS cases in the most metropolitan areas and least in the rural regions. Defective vision at induction also was found in significant excess among the MS cases. The most striking finding was that all the characteristics which served to differentiate MS cases pertained to events that antedated military service, even in those with clinical onset after induction. This indicated therefore, that the determinative events in the acquisition of MS may occur in the early years of life. Although the environmental factors identified here were nonspecific, they indicate that attention should be given to features which distinguished culturally advantaged children in urban communities from the disadvantaged in rural areas during the first half of this century.