3.4 billion people worldwide suffer from neurological problems – that’s 43 percent of humanity. This is the conclusion reached in the latest publication of the “Global Burden of Disease” study series with a view to 2021. According to the analysis, strokes, brain damage in newborns, migraines, dementia and nerve damage from diabetes have contributed the most to the global burden of neurological diseases. The study, with Jaimie Steinmetz from the University of Washington in Seattle as lead author, was published in the journal “The Lancet Neurology”.
Overall, the number of cases for diseases of the nervous system has increased by 59 percent worldwide since 1990, Steinmetz is quoted as saying in a statement in the specialist journal. The international group of authors evaluated scientific studies that were published on this topic between January 1980 and October 2023. Development trends in individual diseases were also analyzed for the period 1990 to 2021.
Lost years of healthy life
A core method of Global Burden of Disease studies is the Daly concept. Daly stands for “disability-adjusted life years”. The years that a person is disabled or restricted by an illness, as well as illness-related deaths, are compared with a fictitious healthy life up to the age of life expectancy. As the current work describes, the number of Dalys has increased from 375 million in 1990 to 443 million in 2021 due to 37 neurological diseases taken into account.
However, the world population has grown during this time and, on average, has become older. If this is taken into account statistically, Dalys caused by neurological diseases have decreased by 27 percent and deaths by 34 percent since 1990 – a development that varies greatly with regard to individual diseases. With the global spread of diabetes, the nerve damage associated with the disease increased by 92 percent during the study period. Neurological diseases caused by sepsis in newborns (70 percent) and malaria (54 percent) have also become significantly more common. On the other hand, the Dalys have decreased significantly due to strokes (- 39 percent), meningitis or meningitis (- 62 percent), rabies (- 70 percent) and tetanus (- 93 percent).
Unequal distribution in the world
Another finding of the work: The burden of neurological diseases is very unevenly distributed in the world. They are lowest in high-income countries in the Asia-Pacific region, such as Japan and South Korea, as well as Australia and New Zealand, and highest in West and Central Africa. The global average is 5637.6 Dalys and 139 deaths per year per 100,000 people. Germany is doing much better with 3299.4 Dalys and 71.7 deaths per year per 100,000 people. The better medical care compared to large parts of the world is probably at work here.
“Health loss from diseases of the nervous system disproportionately affects many of the poorest countries, partly due to the higher prevalence of diseases in newborns and children under five,” said Tarun Dua of the World Health Organization (WHO), another author of the study. Many of the diseases examined for the first time primarily affect children, whose cases account for around 18 percent of neurological diseases worldwide. The most serious illnesses were brain damage in newborns, meningitis and damage to the neural tube.
Gender differences
The frequencies of neurological diseases are also unevenly distributed between the sexes. While Covid-19, multiple sclerosis and migraines affect significantly more women than men, the opposite is true for attention deficit hyperactivity disorder, traumatic brain injury and autism spectrum disorder.
The study also addresses several modifiable risk factors for potentially preventable neurological diseases. By eliminating the most important risk factors – especially high blood pressure and air pollution – up to 84 percent of Dalys could be prevented from having strokes.
“Neurological diseases cause great suffering for the people and families affected and deprive communities and economies of their human capital,” WHO Director-General Tedros Adhanom Ghebreyesus said in a statement. “This study should be an urgent call to action to strengthen targeted interventions so that the growing number of people with neurological diseases can access the high-quality care, treatment and rehabilitation they need.”
