The Worldwide Burden of Migraine Remains High

By Freda Kreier | June 10, 2024 | Posted in

A new analysis of Global Burden of Disease data from 37 disorders affecting the nervous system finds that migraine ranks third globally in terms of disability-adjusted life-years.

The most comprehensive estimate to date of the global burden of disorders affecting the nervous system ranks migraine as the third most burdensome condition globally. Measured in terms of disability-adjusted life-years (DALYs) – one DALY represents one lost year of healthy life – the burden remained high throughout geographical regions and throughout age groups.

This new examination of Global Burden of Disease (GBD) data also confirms the well-known gender disparity in the prevalence of migraine, with migraine having the third largest female-to-male prevalence ratio of all the disorders considered in the study, trailing only neurological complications of COVID-19 and multiple sclerosis.

“If you want to understand what the most important neurological disorders are in the world, this sort of paper gives you an idea,” said Richard Lipton, a neurologist and epidemiologist at the Albert Einstein College of Medicine, New York City, US, who was not involved in the study.

The huge global burden of migraine makes sense considering the disorder is “so common, so long lasting, so widely distributed around the world. No group is spared migraine as far as we know,” Lipton told Migraine Science Collaborative.

The findings appeared in the April 2024 issue of Lancet Neurology.

The overall toll …
Advocates for better migraine treatment and increased funding for research have long pointed to studies showing that the condition can be incredibly disabling. Putting firm numbers on migraine burden matters greatly so that policymakers know where and how to invest limited resources.

A major and long-running effort toward quantifying the impact of disease throughout the world is the GBD study (Global Burden of Diseases, Injuries, and Risk Factors Study), which is “the largest and most comprehensive effort to quantify health loss across places and over time, so health systems can be improved and disparities eliminated,” according to the Institute for Health Metrics and Evaluation (IHME) website.

The GBD initiative, which is now led by the IHME at the University of Washington, Seattle, US, began in the 1990s and has since estimated the burden of more than 450 health outcomes and risk factors across more than 200 countries and territories throughout the world. A collaborative effort amongst more than 11,000 researchers, GBD is one of the most well-known and established sources of epidemiological data in the world.

For the new study, which covers the time period from 1990 to 2021, researchers looked at the global, regional, and national burden of 37 disorders affecting the nervous system across 204 countries and territories – a “bespoke aggregation of everything neurologists are interested in,” said Theo Vos, a population health measurement researcher at IHME and one of the authors on the paper, in an interview with MSC.

What makes the current work stand out is that it included, for the first time, neurodevelopmental disorders and some congenital, neonatal, and infectious conditions that can damage the nervous system. The new work’s inclusion of 37 disorders outpaced the 15 conditions included in the previous analysis of GBD data on nervous system disorders that covered the years 2015 to 2016. (Migraine was included in the earlier investigation.)

These latest and most comprehensive findings now confirm the remarkable toll of conditions affecting the nervous system, with 3.4 billion people globally – 43.1% of the world population – experiencing one of these conditions in 2021.

The 443 million DALYs estimated from the new study’s expanded list of conditions made these conditions the number one worldwide contributor to DALYs, outpacing cardiovascular diseases (excluding stroke), the number two contributor. Conditions affecting the nervous system were also the number one contributor to years of life lost due to premature mortality (YLLs).

… and the specific – and large – contribution of migraine
Consistent with the previous study from 2015 to 2016, globally, amongst the 37 conditions considered in the new work, migraine was the third greatest contributor to DALYs in 2021, with more than a billion people living with the condition. Only stroke and neonatal encephalopathy ranked higher, with migraine outpacing conditions, such as dementia, that receive far more research funding. (Neonatal encephalopathy is the term for brain damage in those surviving birth trauma/asphyxia; most of the DALYs in that instance come from mortality.)

Further, the toll of migraine was high in every specific region considered in the study: From Asia and Europe to Latin America and Africa, in low-income countries and in high-income countries, migraine never came in lower than sixth place in terms of DALY rates.

“Migraine stands out as having a much larger burden than things that people otherwise would say are top neurological conditions, like Parkinson’s disease or epilepsy,” said Vos. These results prove that migraine is “pretty common and rather disabling.”

On the brighter side, the researchers also found that the global prevalence of migraine increased by only 1.6% between 1990 and 2021. Years lived with disability (YLDs) only rose by around 0.6%. (DALYs are the sum of YLDs and YLLs.) “Prevalence seems quite stable,” Lipton said.

In contrast, for many other conditions affecting the nervous system from 1990 to 2021, these measures fell or rose dramatically during this time.

Regarding the trends, Vos said the steadiness in the numbers of DALYs and YLDs resulting from migraine might be because the analysis is not refined enough to pick up on the benefits of new treatments for migraine. Another possibility is that, as the condition becomes more widely understood in some corners of the medical field, an increase in diagnoses might mask the effect of these new treatments, said Lipton.

An unequal burden
The study also revealed regional variation in who lives with migraine. The highest rates of age-standardized DALYs in 2021 were in eastern and central sub-Saharan Africa. Australasia had the lowest rates.

The root cause of these differences isn’t clear. But, as the study authors note, wealthy nations have better access to neurological care, with 70 times more neurological professionals per 100,000 people in high-income countries compared to low-income countries.

The study also corroborated other well-known disparities. For instance, migraine was most prevalent in people between the ages of 20 to 59 years, though no age group except those 0 to 5 years old were migraine free. Migraine was also more prevalent and responsible for more DALYs in women than in men, echoing other studies documenting gender disparities in migraine. In fact, the prevalence of neurological conditions in females was higher globally, a trend driven largely by the fact that women were more likely to experience migraine and tension-type headache (TTH).

Speaking of TTH, more than two billion people had TTH in 2021. But, in contrast to migraine, TTH made a relatively low contribution to disability, with just 4.6 million associated YLDs, despite its high prevalence.

Why it matters
Analyses of GBD data like the current analysis can help policymakers re-evaluate which diseases to prioritize from a funding perspective, said Lipton. For instance, in the 1990s, the IHME added mental health disorders to its metrics, bringing attention to a number of conditions that were not taken very seriously at the time. Something similar could happen with migraine, said Vos.

Through these data, “we can give much more prominence to diseases that tend not to be on people’s radar,” like migraine, said Vos.

That would be a welcome outcome, considering, for example, that US National Institutes of Health (NIH) funding for migraine-related projects pales in comparison to other chronic diseases that have much lower prevalence, fewer associated DALYs, and more modest economic costs – here’s the title of a recent Perspective in Headache from co-authors Serena Orr, University of Calgary, Canada, and Robert Shapiro, University of Vermont, US, that aptly describes this current state of affairs: “The elephant in the room: How the underfunding of headache research stunts the field.”

Freda Kreier is a freelance science journalist based out of Washington, DC.

Global, regional, and national burden of disorders affecting the nervous system, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021.
GBD 2021 Nervous System Disorders Collaborators
Lancet Neurol. 2024 Apr;23(4):344-81.

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