A new major study published by The Lancet Neurology, with contributions from the World Health Organization (WHO) in data analysis, revealed today in Geneva that more than 3 billion people worldwide lived with a neurological condition in 2021. This means that more than one in three people globally suffers from neurological diseases. The international organization confirmed that neurological conditions have now become the leading cause of morbidity and disability worldwide, with the total number of disability-adjusted life years (DALYs) resulting from neurological conditions increasing by 18% since 1990.
The study noted that over 80% of neurological deaths and health loss occur in low- and middle-income countries, and access to treatment varies significantly, with high-income countries having up to 70 times more neurologists per 100,000 people compared to low- and middle-income countries.
The study identified the top 10 neurological conditions that contributed to health loss in 2021: stroke, neonatal brain injury, migraine, dementia, diabetic neuropathy, meningitis, epilepsy, neurological complications from preterm birth, autism spectrum disorder, and central nervous system cancer. It warned that neurological conditions generally cause more disability and health loss in men compared to women, although some conditions like migraine and dementia disproportionately affect women.
The study indicated that since 1990, the absolute number of individuals suffering from or dying due to neurological conditions has increased, while age-standardized disability rates have declined, indicating that this increase in absolute numbers is primarily driven by demographic changes and longer life expectancies.
The study found that diabetic neuropathy was the fastest-growing neurological condition, with the number of individuals suffering from it more than tripling globally since 1990, reaching 206 million cases in 2021. This increase coincides with the global rise in diabetes incidence. Other conditions, such as neurological complications arising from COVID-19 (e.g., cognitive impairment and Guillain-Barré syndrome), were previously unrecorded and now represent over 23 million cases.
The study examined 20 modifiable risk factors for preventable neurological conditions like stroke, dementia, and idiopathic intellectual disability. The WHO emphasized that eliminating key risk factors, particularly high systolic blood pressure and ambient and household air pollution, could prevent up to 84% of stroke-related DALYs. Similarly, preventing exposure to lead could reduce the burden of idiopathic intellectual disability by 63.1%, while reducing elevated fasting plasma glucose levels could lower the burden of dementia by 14.6%.
The WHO confirmed that smoking significantly contributed to the risk of stroke, dementia, and multiple sclerosis.
