Burden of Multiple Sclerosis in the Nordic Region, 1990-2023, and Projection to 2050: A Systematic Analysis Based on the Global Burden of Disease Study 2023.

Background Multiple sclerosis (MS) is a leading cause of non-traumatic neurological disability in young and middle-aged adults, with the Nordic region exhibiting among the highest burdens globally. However, systematic comparisons of MS burden across all five Nordic countries using standardized methodologies remain scarce. Methods Using data from the Global Burden of Disease Study 2023, we analyzed MS burden in Denmark, Finland, Iceland, Norway, and Sweden from 1990 to 2023. Core indicators included incidence, prevalence, deaths, and disability-adjusted life years (DALYs). We calculated estimated annual percentage changes (EAPC), performed joinpoint regression to identify trend inflection points, conducted decomposition analysis to quantify drivers of burden changes, and employed Bayesian age-period-cohort models to project burden to 2050. Results From 1990 to 2023, MS burden in the Nordic region increased steadily. In 2023, age-standardized prevalence was 130.52 per 100,000 population (50,107 cases), with an EAPC of 0.9335. Incidence rose to 4.95 per 100,000 (EAPC = 0.7845), while ASDR increased modestly (EAPC = 0.2550). Finland showed the fastest growth in incidence and prevalence, whereas Sweden and Iceland exhibited stabilization after 2012 and 2014, respectively. Decomposition analysis revealed that population growth and epidemiological changes were the primary drivers of increased burden, contributing 38.39-71.08% and 23.85-71.62% to prevalence growth, respectively. Projections to 2050 indicate that prevalence will increase by 19.5% to 156.01 per 100,000 (67,846 cases), with a narrowing but persistent female predominance. Conclusion The rising MS burden in the Nordic region is driven primarily by population growth and epidemiological changes. Universal healthcare has enabled early access to disease-modifying therapies, sustaining low ASDR in most countries. However, aging populations and prolonged survival present emerging challenges, underscoring the need for tailored national strategies and cross-Nordic collaboration.