EPIDEMIC OPTIC NEUROPATHY IN CUBA - CLINICAL CHARACTERIZATION AND RISK-FACTORS

Background. From 1991 to 1993, epidemic optic and peripheral neuropath y affected more than 50,000 people in Cuba. The number of new cases de creased after the initiation of vitamin supplementation in the populat ion. In September 1993, Cuban and U.S. investigators conducted a study to characterize and identify risk factors for the optic form of the s yndrome. Methods. We conducted ophthalmologic and neurologic examinati ons, assessed exposure to potential toxins, administered a semiquantit ative food-frequency questionnaire, and assessed serum measures of nut ritional status in 123 patients with severe optic neuropathy, matched for sex and age to randomly chosen normal subjects. Results. In the ca se patients, prominent clinical features were subacute loss of visual acuity with field defects, diminished color vision, optic-nerve pallor , and decreased sensitivity to vibration and temperature in the legs. Tobacco use, particularly cigar smoking, was associated with an increa sed risk of optic neuropathy. The risk was reduced among subjects with higher dietary intakes of methionine, vitamin B-12, riboflavin, and n iacin and higher serum concentrations of antioxidant carotenoids, The risk was also reduced among subjects who raised chickens at home or ha d relatives living overseas - factors that may be indirect measures of increased food availability. Conclusions. The epidemic of optic and p eripheral neuropathy in Cuba between 1991 and 1993 appears to be linke d to reduced nutrient intake caused by the country's deteriorating eco nomic situation and the high prevalence of tobacco use.