Multiple sclerosis: some epidemiological clues to etiology.

The diagnosis of multiple sclerosis is frequently made with undue haste and without a firm basis. A false positive diagnosis is made in about 20 to 30% of the cases originally labeled as multiple sclerosis. The proportion of false positive diagnosis is probably still higher in countries where this disease is less frequent. An exhaustive investigation (neurological, clinical, neurorradiological, isotopic, etc.) is necessary before accepting such a diagnosis. This is particularly important because many of the lesions which can masquerade as multiple sclerosis are amenable to medical or surgical treatment. The prevalence of multiple sclerosis varies widely throughout the world, with a very definite preference for the white race. This difference seems to be caused, at least in part, by dietary habits. Lack of breastfeeding and excessive consumption of cow's milk during infancy is postulated as an important factor in the appearance of multiple sclerosis later in life. A lack of essential fatty acids (and may be of certain minerals and vitamins) in such a diet during pregnancy and childhood may result in the synthesis of abnormally unstable myelin. This underlying deficiency in myelin composition may be the substrate on which immunological factors act to produce the disease. The breakdown of this unstable myelin may be initiated by a variety of factors; natural decay of abnormally weak bonds in proteolipids, viral infection, immune reactions or even trauma. Immune reactions can explain, at least in part, the onset and the course of the disease, and probably immunodeficiency is the most important factor. Demyelination, once it starts, may continue until all abnormally formed myelin is destroyed, or until the building up of immunological defenses can stop the process. It follows from this that prevention of multiple sclerosis should be based mainly on dietic measures which ensure a sufficient supply of essential fatty acids, minerals and vitamins, during pregnancy and childhood. Breast feeding is probably the most important preventive factor. Skin pigmentation, either natural or from exposition to sunshine also seems to act as a preventive factor, and its mode of action deserves further investigation. Treatment of multiple sclerosis should be based on the improvement of immunological defenses, the elimination of possible allergens and saturated fats from the diet, and on the administration of sufficient amounts of essential fatty acids and of other various elements.