Global Burden of Brain Disorders Surpasses CVD, Cancer

Liam Davenport

July 12, 2023

Brain disorders, including mental illness, neurologic conditions, and stroke, account for more than 15% of all health loss worldwide — more than either cardiovascular disease or cancer — at huge cost to healthcare systems and society, an analysis of data from the most recent Global Burden of Disease (GBD) study shows.

"The burden of brain conditions will increase as populations continue to grow and age," said study presenter Shayla Smith, MPH, an epidemiologist at the Institute for Health Metrics and Evaluation (IHME), the University of Washington, Seattle, Washington, in a press release.

"By 2050, more than 50 million people will be aged 65 to 79," she explained, adding that the COVID-19 pandemic "has also influenced the prevalence of mental disorders globally, as people were forced to isolate and social networks broke down."

Other factors related to brain disorders, she noted, include education level, obesity, and smoking.

"There's still research to be done on what is the most effective way to maintain brain health, but some literature suggests a healthy brain can be achieved through a healthy lifestyle of managing conditions such as high blood pressure and diabetes, limiting alcohol consumption and smoking, prioritizing sleep, eating healthy, and staying physically and mentally active," said Smith.

The findings were presented at the Congress of the European Academy of Neurology (EAN) 2023.

An "Ambitious Exercise"

Co-investigator Xaviera Steele, also from the IHME, told a press conference that the institute was established at the University of Washington in 2007 with the aim of "standardizing the measurement of health outcomes around the world and for all health conditions."

A central part of that is the GBD study, "which is a very ambitious exercise in descriptive epidemiology in an effort to systematically quantify health loss" due to disease, injury, and risk factors over time, stratified by country, region, age, and sex.

In addition, researchers are mapping and projecting trends over the next century and are estimating disease expenditure by country, by type of expense, and by condition "to derive a healthcare access and quality score for each health system in the world," Steele said.

They are also estimating exposure to risk factors, how those risk factors contribute to health burden, and associated health outcomes by race and ethnicity to reflect the "disparities that we know are very prevalent in countries such as the United States."

From that work, Steele said that brain health and related conditions "do emerge as one of the more pressing challenges of the 21st century."

Increase in Dementia, Mental Health Conditions

The data, which were gathered from 200,000 sources by the IHME, indicate that the number of individuals aged ≥65 years will increase by 350% by 2100.

Steele underlined that "policy action will be needed to help families, who will struggle to provide high-quality care for their loved ones with dementia at a reasonable cost."

The IHME calculates that in Europe, healthcare spending on Alzheimer's will increase by 226% between 2015 and 2040.

Turning to other conditions, Steele showed that since 1990, the number of individuals living with anxiety in the European region has increased by 14%, while the number living with depressive disorders has gone up by 13%.

Worldwide, the figures are even starker. Depression is estimated to affect 300 million people across the globe, which represents a 71% increase since 1990. The number of strokes increased by 95% over the same period.

Nevertheless, the "impact of brain conditions such as stroke has decreased since the 1990s due to improved treatments available," Smith noted in the press release.

To estimate the toll caused by brain conditions, including neurologic disorders, mental disorders, cerebrovascular disease, brain cancer, brain injuries, and select infectious conditions, the researchers calculated disability-adjusted life years (DALYs).

This, Smith explained in her presentation, "captures the morbidity and mortality associated with brain conditions" and is adjusted for patient location, age, and sex.

The investigators found that globally, brain conditions accounted for more than 15% of all health loss in 2021, at 406 DALYs. More than the 206 million DALYs were associated with cancer, and the 402 million were linked to cardiovascular disease.

This health loss is associated with a $1.22 trillion loss in income for people living with health disorders worldwide and accounts for $1.14 trillion in direct healthcare costs.

The burden of mental disorders, neurologic conditions, and stroke is expected to increase dramatically between now and 2050, said Smith, who noted that health loss linked to brain conditions is higher in younger patients.

This will create "new challenges for health systems, employers, patients, and families," she said in the press release.

"Our goal is to see an improved prevention and treatment landscape for other brain conditions and reverse the growing health loss that we are currently forecasting."

Worrying Increase in Stroke

Jurgita Valaikiene, MD, PhD, Center of Neurology, Clinic of Neurology and Neurosurgery, Vilnius University Faculty of Medicine, Vilnius, Lithuania, who chaired the session, was taken aback by the findings, particularly by the worldwide increase in stroke cases.

"I work in stroke," she told Medscape Medical News, and "we spend a lot of time on the diagnosis of stroke" and its prevention.

"We try to be faster, to catch asymptomatic stenosis in the neck or head, and to apply the best medical treatment to avoid a stroke. But despite that, the numbers are increasing. I understand the population is getting older,... but still it's a huge number."

Valaikiene pointed out that stroke is not necessarily a condition of aging, insofar as increasing age "is not related directly to stenosis in the neck.

"For example, we can have healthier vessels in older age and unhealthy vessels, with high-grade stenosis, in someone aged 30 or 40 years.

"There are a lot of risk factors, such as smoking, physical activity, and so on. It depends on the individual," she added.

The study was funded by the Institute for Health Metrics and Evaluation at the University of Washington. The authors have disclosed no relevant financial relationships.

Congress of the European Academy of Neurology (EAN) 2023: Abstract EPO-236. Presented July 2, 2023.

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