Multiple sclerosis in diverse populations: characteristics in distinct Arab ethnicities in Israel.

Background: Multiple sclerosis (MS) prevalence and genetic susceptibility varies among the different ethnic groups of Jews and Arabs in Israel. Objective: Characterization of MS disease course in Christian, Muslim and Druze Arabs in Israel. Methods: Historical cohort and three-year follow-up cohort analyses based on interviews and clinical charts of 149 Arab MS patients (78 Muslims, 49 Christians and 22 Druze) from three MS centers in Israel. Significant findings were adjusted for use of disease modifying therapy. Results: Age of onset (means between 30 and 31 years) and incomplete recovery rates after the first relapse (similar to 50%) were similar for Christian, Muslim and Druze patients. Low rates of primary progressive MS (<= 1%) were observed. Differences between the ethnicities in the time from onset to the second neurological episode were observed among females, but not males. Druze and Muslim women were more likely to have a second event within two years from the first event compared with Christians (odds ratios =8.8, p=0.02; odds ratio=6.6, p=0.007 respectively). Trends for higher annual relapse rates, annual disability progression rates and MS Severity Scores were observed among the Druze. Conclusions: Among the Israeli Arab female MS patients, Druze and Muslims exhibit a more rapid disease course in comparison with Christians. Further elucidation of population-specific MS phenotypes may contribute to improved disease management.