Analytical epidemiology of multiple sclerosis in the Republic of Kabardino-Balkaria

Abstract

Multiple sclerosis (MS) is a common autoimmune disease, which etiology includes a complex of genetic and environmental factors. Data suggests that their interaction can influence the age of the clinical manifestations and the course of the disease. Therefore, the study of risk factors of MS in regions with different ethnic compositions of the population and climatic and geographical characteristics is of considerable interest.Objective: to study MS risk factors prevalence in the Republic of Kabardino-Balkaria (RKB).Patients and methods. This case-control study of the representation of risk factors included a cohort of 112 MS patients living in two regions of the RKB (Nalchik and the Prokhladnensky district). The MS diagnosis was established with the McDonald criteria (2017). MS risk factors were assessed with a unified questionnaire. 112 respondents (matched by the main demographic characteristics and place of residence) were included in the control group.Results and discussion. MS patients from the Prokhladnensky district were significantly more likely to contact harmful chemical compounds, had higher consumption of smoked meat products; and suffered from viral infections more often (all differences were significant, p<0.05). More patients with MS, regardless of their place of residence, had a history of scarlet fever than the controls (n=23; 19.5% and n=14; 13.4%, ratio indicator 0.43 (95% CI 0.32–1.01), p=0.041), and the maximum significance of this factor was found in patients who suffered from scarlet fever after the age of 15 years (n=7; 6.3% and n=1; 0.9%, ratio indicator 2.45 (95% CI 1.92–3.21), p=0.041). More patients with MS had a history of chickenpox (n=70; 62.5% and n=55; 41.1%; ratio indicator 0.78 (95% CI 0.65–0.94, p=0.032), the frequency of this factor was most significant in early (up to 7 years) disease onset. Regardless of the place of residence, patients with MS were more likely to suffer from tonsillitis and sinusitis in childhood (p=0.032).Conclusion. In the RKB, as in other regions of the Russian Federation, the risk of MS, along with a genetic predisposition, is primarily determined by environmental factors, such as contact with potentially harmful chemicals, history of somatic diseases, characteristics of the ecological situation, etc. Therefore, MS risk is higher in people exposed to these factors before the age of 7 years and does not depend on the place of residence.