Purpose
Healthcare planning and resource allocation require accurate estimates of the burden of motor neuron diseases (MNDs). This study evaluated the global impact of MNDs from 1990 to 2021 as part of the Global Burden of Disease (GBD) Study 2021.
Methods
GBD 2021 data were used to assess the global burden of MNDs from 1990 to 2021 in terms of prevalence, incidence, disability-adjusted life years (DALYs), and deaths. The relationship between MND burden and the Socio-demographic Index (SDI) was also examined.
Results
Globally, MNDs accounted for 272,732 prevalent cases (95% uncertainty interval [UI], 236,195–313,676), 64,178 incident cases (95% UI, 58,506–70,270), 1,040,566 DALYs (95% UI, 963,064–1,123,956), and 39,082 deaths (95% UI, 35,757–42,433) in 2021. The corresponding age-standardized rates per 100,000 people were 3.31 (95% UI, 2.86–3.80) for prevalence, 0.46 (95% UI, 0.42–0.49) for mortality, and 12.17 (95% UI, 11.24–13.15) for DALYs. From 1990 to 2021, the numbers of prevalent and incident cases increased, but their age-standardized rates decreased by 1.36% and 4.69%, respectively. By contrast, the age-standardized mortality rate increased by 19.84%. MND burden was generally higher in regions with a high SDI, although rates in high-income Asia Pacific were relatively low compared with those in regions with similar SDI values.
Conclusion
From 1990 to 2021, the absolute burden of MNDs increased, age-standardized prevalence and incidence rates declined slightly, and mortality-related burden increased. These trends underscore the need for evidence-based national and global healthcare planning. Geographic variation in MND burden may reflect regional differences in the roles of sociodemographic and genetic factors.

Purpose
Neck pain is a leading musculoskeletal cause of disability in the United States. This study aimed to assess temporal, geographic, and demographic disparities in its burden across US states from 1990 to 2021.
Methods
Global Burden of Disease 2021 data for all 50 US states and the District of Columbia were analyzed for 1990–2021. Counts and age-standardized rates per 100,000 population for prevalence, incidence, and years lived with disability (YLD) were compared by region, state, sex, age group, and sociodemographic index (SDI) level.
Results
In 2021, neck pain accounted for 9,430,000 (95% uncertainty interval [UI], 7,400,000–11,590,000) prevalent cases, 1,900,000 (95% UI, 1,490,000–2,320,000) incident cases, and 920,000 (95% UI, 620,000–1,300,000) YLD, increases of 41.17%, 37.44%, and 38.72%, respectively, from 1990. Although age-standardized incidence increased globally by 1.18% (0.07%–2.39%) over 1990–2021, the United States had small declines in age-standardized incidence (−0.11%; 95% UI, −0.18% to −0.06%), prevalence (−0.20%; 95% UI, −0.32% to −0.10%), and YLD (−1.12%; 95% UI, −2.02% to −0.22%). Neck pain rates were highest in the District of Columbia, Georgia, and Delaware and lowest in North Carolina, Alaska, and Wyoming. The burden peaked at ages 40–49 years and was higher in females. Age-standardized YLD rates for neck pain were significantly positively correlated with the SDI (Spearman’s ρ=0.601, P<0.001).
Conclusion
The geographic and demographic disparities in neck pain burden across US states indicate a need for targeted interventions.