[Epidemiology of multiple sclerosis in the city of Novosibirsk]

To study the dynamics of the epidemiological characteristics of multiple sclerosis (MS) from 01.01.2003 to 01.01.2024 in Novosibirsk in comparison with the previous 20-year study.

The prevalence cohort included 2254 patients with MS living in Novosibirsk on 01.01.2024. The cohort of cases included 1998 patients with the onset of the disease from 01.01.2003 to 31.12.2023 inclusive. In order to level out the influence of heterogeneous sex and age composition of the population of Novosibirsk, the method of standardization of indicators was used in the study (standard European population, 13.07.2013). The results of our analysis were compared with the results of the previous epidemiological study in the city of Novosibirsk (Malkova N.A., 2005).

The prevalence of MS as of 01.01.2024 was calculated as 137.83 per 100 thousand population (standardized indicator - 123.43). The average age of the patients with MS was 46.146±0.479 years. The ratio of men to women was 1:2.1. The incidence of MS from 2003 to 2023 shows a trend toward an increase (5.12±0.0662 to 7.71±0.0246 per 100 thousand population/year (p<0.05), which is mainly due to a significant increase in the proportion of women (6.56±0.1118 to 11.01±0.091 per 100 thousand population/year, p<0.05), but not men (p>0.05). The average age of MS onset increased by 0.146 years annually during the study period and amounted to 30.479±0.329 years (r_xy=0.08, p<0.001). An increase in the incidence of early-onset and late-onset MS was also noted (r_xy=0.45, p=0.041 and r_xy=0.622, p=0.003, respectively). A significant decrease in the «onset-diagnosis» interval was recorded (mean 5.28±6.41 years on 01.01.2003; mean 1.77±0.921 years on 01.01.2024).

In the era of controlled disease progression, our study showed an increase in the prevalence of MS from 2003 to 2023 (54.4 to 137.83 per 100 thousand population). The dynamics of the sex ratio of patients with MS in Novosibirsk does not demonstrate the global trend with a 3-4-fold increase in the proportion of women. An increase in the incidence of MS was noted from 2003 to 2023 (p<0.05), mainly due to women (p<0.05). The age of MS onset has increased significantly over the 20-year period (27.73±0.6 years in 2003; 30.479±0.329 years in 2023). A separate trend towards an increase in the incidence of early-onset and late-onset MS is shown (r_xy=0.45, p=0.041 and r_xy=0.622, p=0.003, respectively). In part, the increase in the epidemiological characteristics of MS is associated with a decrease in the «onset-diagnosis» interval (p<0.05), which is due to improved diagnostic criteria and health care services.