Comparison between multiple sclerosis in India and the United States: a case-control study.

The prevalence of MS in India is low, and it is unclear whether the manifestations of the disease in India are similar to the United States. We carried out a case-control study to compare the disease in the two populations and used clinical, evoked potential, and MRI criteria to assess similarities and differences. Our results indicate that the rate of disease progression and frequency of involvement of the cerebral hemispheres, cerebellum, spinal cord, and brainstem were similar in the two populations. The visual system was more frequently involved in Indian patients. No Indian patient had a family history of MS; this suggests an environmental disease-triggering agent.