Environmental risk factors in MS: a case-control study in Moscow.

Environmental influences operating as possible risk factors in MS were studied in Moscow. The study included 155 MS patients from the Neurology Departments and the outpatient clinics of the First City Hospital of Moscow and 155 controls matched for sex, age in 5-year intervals, nationality, and origin (Moscow vs. non Moscow). 72.3% of controls were recruited among patients from the same hospital as the cases. The remaining controls were volunteers from the hospital staff or medical students. Exposures before age 15 were of special interest. MS patients reported a higher frequency of: 1) tonsillitis; 2) allergic reactions after age 15; 3) head trauma below age 16; 4) a predominant meat vs. vegetable diet during childhood. Stratified analysis and logistic regression pointed to meat predominance as the most significant risk factor. Other associations were confounded by the respondents' occupation/education.