Over 3 Billion People Now Live with a Neurological Condition: What Does This Mean?

Over 3 Billion People Now Live with a Neurological Condition: What Does This Mean?
  • New research shows that over 3.4 billion people throughout the world have a neurological condition.
  • These conditions include neurodevelopmental disorders such as autism, neurodegenerative disorders such as Alzheimer’s, and movement disorders such as Parkinson’s.
  • A concerning aspect of the findings is that disability and deaths related to these conditions increased by 18% since 1990.
  • The researchers hope that the findings will increase awareness of neurological conditions and encourage public health officials across the world to invest in brain health and expanding healthcare.

The World Health Organization (WHO) recently contributed to a new study that took a look at how neurological conditions affect people across the globe.

After analyzing data available from the Global Burden of Disease, Injuries, and Risk Factor Study (GBD) 2021, the researchers learned that around 3.4 billion people have a neurological condition. Additionally, neurological conditions are now the leading cause of disability.

The rise in neurological conditions is associated with an increase in premature deaths. The majority of these deaths occur in low and middle-income countries where neurological healthcare is limited.

The study appears in The Lancet Neurology.

Stroke, Alzheimer’s, and more on the rise

The GBD report includes data on health loss worldwide from 1990 to 2021 – the data includes 371 diseases and spans more than 200 countries and territories.

The researchers for the present study focused on health loss that affects the nervous system including both neurological conditions and neurodevelopmental disorders. Some of these conditions include:

  • Stroke
  • Alzheimer’s disease
  • Autism Spectrum Disorder
  • encephalitis and meningitis
  • Parkinson’s disease
  • Multiple Sclerosis (MS)

The study authors also factored in the neurological effects of conditions that are not neurological in nature.

For example, the authors took cognitive symptoms following COVID-19 infections into consideration in their analysis for people with “persistent cognitive symptoms and Guillain-Barré syndrome.”

While conducting their analysis, the study authors calculated years lived with disability to get an idea of the non-fatal burden of these conditions. They next looked at deaths and years of life lost as well as premature death.

The authors also calculated the disability-adjusted life-years, which factored in the years lived with disability and years of life lost “by year, age, sex, and location, and represent the combined non-fatal and fatal burden of each condition.”

Another important aspect of the authors’ analysis was focusing on the location of the people affected by these neurological conditions.

The authors classified people based on whether they lived in a low-income or middle-income country. According to the authors, they calculated this by “using World Bank income levels, which are based on gross national income per capita.”

Over 10 neurological conditions

According to the study findings, neurological conditions are the leading cause of disability worldwide. They estimated these conditions affected more than 3.4 billion people, which is 43.1% of the global population.

The authors identified the top neurological conditions based on the GBD report that contributed to health loss, which included stroke, neonatal encephalopathy, migraine, Alzheimer’s disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.

Not only are neurological conditions the leading cause of disability, but the findings also show an 18% increase in disability, illness, and early death caused by these conditions since 1990.

The authors said diabetic neuropathy was the condition with the fastest growth overall and that its prevalence increased three-fold since 1990. Diabetic neuropathy causes nerve damage in the feet and legs and can lead to infections and amputations.

COVID-19 may also be to blame for part of the increase in disability related to neurological conditions. COVID-19 can cause long-term cognitive impairment and Guillain-Barré syndrome.

Another concerning study finding is that people in low and middle-income countries are disproportionately affected by neurological conditions. More than 80% of neurological deaths occurred in these countries.

The authors noted one positive finding in their analysis of the GBD report – health loss due to conditions such as tetanus, rabies, and stroke went down by 25% since 1990. The authors attribute this to improved prevention and care.

The authors said there are some modifiable risk factors public health officials can focus on to reduce the chances of developing one of these conditions, such as limiting lead exposure and reducing plasma glucose.

The WHO is also making neurological disorders a focus to improve healthcare access to manage these conditions.

Dr. Muhammad Arshad, a neurologist with Memorial Hermann in Houston, who was not involved in the study, underlined the importance of the findings from a public health standpoint.

“The findings in this study have important health service and policy implications and serve as evidence that global neurological health loss has been under-recognized and is increasing and unevenly distributed geographically and socioeconomically,” commented Dr. Arshad.

Can we prevent neurological conditions?

The study highlights the need for increased preventive measures and improved neurological healthcare, especially among lower and middle-income countries.

Dr. David Merrill, a geriatric psychiatrist and director of the Pacific Neuroscience Institute’s Pacific Brain Health Center in Santa Monica, California, who was also not involved in the study, spoke to Medical News Today about the study.

“Chronic neurologic conditions are now the leading cause of worldwide illness and disability,” commented Dr. Merrill. “When we’re healthy, we tend to think of neurologic conditions as rare, but we see the finding is that 1 in 3 individuals are living with a chronic potentially debilitating neurologic illness.”

Dr. Merrill believes it is possible that these conditions have become more prevalent in recent years because of aging. According to the WHO, life expectancy is increasing, with the average going from 66.8 years in 2000 to 73.4 years in 2019.

“Age is the single largest non-modifiable risk factor for dementia, so perhaps an aging world has contributed in part to the increasing levels of neurologic conditions in recent years,” said Dr. Merrill.

While the outlook for neurological conditions seems grim, Dr. Merrill noted that people can make changes to decrease their likelihood of developing some neurological conditions.

“Our health-related behaviors make a difference. We can lower our risk of developing chronic neurologic conditions like dementia through optimizing our lifestyle-related behaviors. That includes regular exercise, socializing, cognitive stimulation, and a healthy diet.”
— Dr. David Merrill

Dr. David Cutler, board certified family medicine physician at Providence Saint John’s Health Center in Santa Monica, California, who was not involved in the study, also spoke with MNTabout the findings.

Dr. Cutler emphasized the importance of prevention of neurological conditions.

“One significant impact of these findings should be a greater focus on prevention rather than treatment of neurological conditions,” said Dr. Cutler. “For example, rather than a focus on treating stroke with complex, expensive vascular interventions, we should focus more on controlling high blood pressure and high cholesterol which are major risk factors for stroke.”


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