Kalafatova O I
Acta Neurol Scand. 1987 Mar;75(3):186-9. doi: 10.1111/j.1600-0404.1987.tb07915.x.
An epidemiological study of MS in 5 districts of Bulgaria was carried out over period of 10 years to establish MS prevalence, incidence and mortality. The district of Sofia was the highest, indicating increased prevalence among the urban population, and more female than male cases. In the age group up to 15 years, age at onset was significantly earlier in the urban than in the rural cases.
