Not just dementia and Alzheimer’s: neurological diseases on the rise

Study published in The Lancet shows dramatic increase in neurological diseases worldwide

Cardiovascular diseases are no longer the number one most common disease worldwide. As had already been predicted, this has now been replaced by diseases of the nervous system. Over 3.4 billion people worldwide are affected by neurological disorders, which corresponds to 43 percent of the global population. This is the key finding of the latest publication in the “Global Burden of Disease” study series from the US Institute for Health Metrics and Evaluation (IHME) for 2021.

According to this study, strokes, cerebral damage in newborns, migraines, dementia and diabetic neuropathy are the main causes of the global burden of neurological diseases. Published in the renowned journal “The Lancet Neurology”, the study was conducted under the direction of Jaimie Steinmetz from the University of Washington in Seattle.

Since 1990, the number of cases of diseases of the nervous system has risen by 59 percent worldwide, as Steinmetz reports in a publication in the journal. The group of international authors analyzed scientific studies published in this field between January 1980 and October 2023. They also examined developments in specific neurological diseases in the period from 1990 to 2021.

Increasing burden of neurological diseases: Years of life lost are increasing

The study looked at the impact of 37 different neurological diseases on people’s health, including the incidence of disability and death. A central method of the “Global Burden of Disease” studies is based on the DALY concept, where DALY stands for “disability-adjusted life years”, i.e. “healthy life years lost”. This concept takes into account both the lifetime spent in disability or restriction due to illness and the premature deaths caused by illness, compared to a hypothetical healthy life up to the average expected age. According to the current study, the number of DALYs has risen from 375 million in 1990 to 443 million in 2021.

Strokes led to the most serious consequences, depriving humanity of 160 million healthy life years according to the study. In the following ranks were diseases such as neonatal encephalopathy, migraine, dementia, nerve damage caused by diabetes, meningitis and epilepsy. Perceptual disorders caused by COVID-19 ranked 20th.

Evenly distributed burden: neurological diseases hit poorer countries harder

The study also shows that the burden of neurological diseases is very unevenly distributed worldwide, with the lowest burden in high-income countries in the Asia-Pacific region such as Japan and South Korea, as well as in Australia and New Zealand, and the highest in West and Central Africa. The global average is 5637.6 DALYs and 139 deaths per year per 100,000 inhabitants. Germany has a lower burden with 3299.4 DALYs and 71.7 deaths per year per 100,000 inhabitants, which is probably due to better medical care.

Neurological disease burdens are particularly excessive in the poorest countries, which can be attributed, among other things, to the high number of cases of disease in newborns and children under five years of age,” explains Tarun Dua from the World Health Organization (WHO) and co-author of the study. A considerable proportion of the diseases examined for the first time primarily affect children, who account for around 18 percent of neurological diseases worldwide. The most serious diseases include brain damage in newborns, meningitis and damage to the neural tube.

Finally, the study highlights that by addressing and eliminating the main causes – particularly high blood pressure and air pollution – a significant proportion of neurological diseases, especially strokes, could potentially be avoided. The authors put the potential reduction in the number of cases of disease caused by these burdens at up to 84 percent of the DALYs that could be reduced in this way.

Minimize risk factors: One way to reduce neurological diseases

Neurological diseases cause great suffering for those affected and their families and deprive communities and economies of valuable human capital,” said WHO Director-General Tedros Adhanom Ghebreyesus in a press release on the findings. “This study must be seen as an urgent wake-up call to intensify targeted interventions. The aim is to ensure that the growing number of people with neurological conditions have access to the high-quality care, treatment and rehabilitation they need.”

For the majority of the 37 diseases studied, there is no cure, which underlines the importance of prevention and research into novel interventions, the authors say. An improved understanding of the specific effects of individual diseases on the nervous system should serve as a foundation for targeted actions and policies that can help improve neurological health at an individual and societal level.