Nervous system injuries have become the leading cause of disability worldwide
The Global Burden of Disease Study found that a group of 37 diseases affecting the nervous system can be recognized as the leading group in terms of the number of disability-adjusted years in 2021. These diseases affect 3.4 billion people worldwide, or 43.1 percent of the world's population. However, age-standardized mortality rates associated with these conditions decreased by 33.6 percent from 1990 to 2021. The results of the analysis are published in The Lancet Neurology.
The causes of nervous system disorders can be divided into congenital, in which there are genetic disorders, lack of morphological maturity or malformations of the brain or spinal cord, and acquired due to injuries, infections, systemic diseases, metabolic disorders and tumors. Some diseases of the nervous system result in disability, while others are associated with high mortality rates; some are treatable and preventable, for others there is no cure.
The increasing burden of neurological disease is thought to be related to the aging of the world's population, with an increased risk of age-related neurological disorders such as Alzheimer's disease, other dementias, stroke, and Parkinson's disease. However, it is clear that not all of this burden is due to population aging, and it is important to quantify the contribution of other nervous system disorders to the overall burden of disease. This assessment will enable health care resources to be more appropriately allocated to achieve the greatest coverage of prevention, diagnosis and treatment of neurological diseases.
The Global Collaboration on the Burden of Nervous System Disease studied mortality, prevalence, expected years of working life lost, expected years of life lost, and disability-adjusted life years (disability-adjusted life years) by age and sex in 204 countries and territories from 1990 to 2021. In 2021, scientists estimated that 3.4 billion people worldwide in 2021 had one of 37 diseases that affect the nervous system, corresponding to 43.1 percent of the world's population. The estimate included developmental disorders of the nervous system, neurological diseases and neurological complications of other congenital, perinatal, metabolic or infectious diseases.
Cumulatively, all of these conditions caused 11.1 million deaths and resulted in 168 million expected years of working life lost, 275 million expected years of life lost. The number of disability-adjusted life years totaled 443 million, overtaking the cardiovascular disease group (excluding stroke). Between 1990 and 2021, the number of disability-adjusted life years due to neurologic disease increased by 18.2 percent. However, the age-standardized rate decreased by 27 percent just as the age-standardized mortality rate decreased by 33.6 percent.
At the regional level, age-standardized disability-adjusted life years were highest in sub-Saharan West Africa and sub-Saharan Central Africa and lowest in Australia and Oceania and high-income Asia and the Pacific. And the greatest differences were observed for children under five years of age, among whom neonatal encephalopathy, meningitis and neural tube developmental defects were the most common conditions. The overall average prevalence of cases of nervous system disorders in Russia in 2021 was 45245.5 per 100,000 population, with a mortality rate of 166.6 per 100,000 population.
For adults aged 20-59 years, the main diseases were stroke, migraine and diabetic neuropathy, and for adults aged 60-79 years - stroke, Alzheimer's disease and other dementias, as well as diabetic neuropathy. Notably, the rates of disability-adjusted years in 2021 were lower for women than for men.
According to the scientists, the results of this study show that the global burden of neurological diseases is underestimated and the resulting losses are increasing and unevenly distributed across the planet. Coordination of international health communities with national ministries of health can make a difference.