Almost half of the planet suffers from some neurological disease | Health & Wellness

Neurological diseases are already the leading cause of poor health in the world. A study published in the journal The Lancet Neurology has calculated that, in 2021, around 3.4 billion people around the globe – that is, 43% of the world’s population – suffered from some nervous system ailment, such as Alzheimer’s and other dementias, strokes, migraines or autism spectrum disorders. , among others. The research shows that, in the last three decades, the number of people who live with this type of pathology or die from this cause has been increasing (59% and 41%, respectively) due to the aging of the population and the influence of environmental, metabolic or unhealthy lifestyle factors that function as risk factors for some of these pathologies (stroke and dementia, for example). The authors warn of the “enormous” impact on public health of these pathologies and call for the deployment of public policies and resources to respond to the demand for care.

Neurological diseases are an amalgam of pathologies that have damage to the nervous system as a common point. But they are complex and very diverse ailments, both in diagnosis, treatment, prognosis and the health care they require. For example, dementia has little or nothing to do with a neurodevelopmental disorder; or a headache with motor neuron diseases, such as amyotrophic lateral sclerosis (ALS). The point of agreement is that all of them make up a family of very prevalent pathologies that can cause a substantial loss of quality and time of life. According to the 2021 Global Burden of Disease Study (GBD), which quantifies health loss due to 371 diseases in more than 200 countries on a regular basis, neurological ailments—the research brings together 37 pathological conditions within this family—caused more than 11 million deaths in 2021 and contributed to one of the largest global losses in quality of life.

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The study has analyzed classic neurology pathologies, such as stroke or migraine, but has also incorporated, for the first time, pathologies bordering other areas, such as autism spectrum disorder or attention deficit hyperactivity disorder. In addition, it includes new phenomena that have occurred in recent years, such as the neurological conditions associated with Covid (cognitive impairment or Guillain-Barré syndrome) or damage to neurodevelopment in babies whose mothers were infected with the virus during pregnancy. of Zika. “We estimate that 3.4 billion people experienced some neurological health loss in 2021, which is a staggering number. This is largely due to some conditions that are widespread. For example, tension-type headaches affected around 2 billion people in 2021. Our analysis takes into account independent comorbidity between conditions, meaning that a given individual may have more than one illness at the same time,” points out Jaimie Steinmetz, author of the study and researcher at the Institute for Health Metrics and Evaluation at the University of Washington (USA).

To gauge the health impact of these ailments, researchers use disability-adjusted life years (DALYs), an indicator that measures all that time of healthy and full life lost due to the disease, the poor health associated with it, or premature death. According to the study published in The Lancet Neurology, neurological diseases cause, globally, a loss of 443 million healthy life years (DALY), which makes this bag of pathologies the leading cause of poor health and disability in the world, even above the cardiovascular diseases, the authors agree. Since 1990, DALYs caused by neurological diseases have increased by 18%.

“The increase in total DALYs—and the increase in the total number of people living with neurological health loss—is primarily due to population aging and population growth,” Steinmetz says. In fact, many neurological conditions, such as dementia or Parkinson’s, for example, are more common in old age. However, there is the paradox that, if the effect of demographic changes is eliminated and standardization by age is used, the study shows that death rates decrease in some pathologies, such as stroke or neonatal encephalopathy, he adds. the author: “These downward trends are driven by an improvement in mortality prospects, but, on the other hand, greater survival thanks to better care means that we see more years lived with disability in the population. For example, more children with long-term neurological consequences.”

Poor countries most affected

The neurological conditions that cause the most years of healthy life lost are stroke, neonatal encephalopathies, migraine, Alzheimer’s and other dementias, and diabetic neuropathy (nerve damage associated with high blood glucose). Meningitis, epilepsy, neurological complications in premature babies, autism spectrum disorders and cancer of the nervous system are also at the top of the table of pathologies that most affect quality of life. But there are differences by country and by age.

Lower-income regions suffer more from the impact of this group of diseases. In developing territories, such as central and western sub-Saharan Africa, neonatal encephalopathy, meningitis or neural tube defects are some of the conditions that cause the most loss of years of healthy life, while these same Pathologies in high-income regions, such as Australasia, are much less prevalent and their impact is therefore lower. “Nervous system health loss disproportionately affected people in low- and middle-income countries, in part due to a higher prevalence of conditions affecting newborns and children under five,” the authors explain in the article. .

The disease with the most common impact around the globe is stroke: in 19 of the 21 regions analyzed in the study, it is the pathology that most contributes to the loss of healthy years of life. By age, in children under five years of age, the ailments that most affect are neonatal encephalitis, meningitis and neural tube defects; In children and adolescents, the neurological problems associated with prematurity and epilepsy stand out; in adults aged 20 to 59 years, stroke, migraine and diabetic neuropathy are in the lead; and in older age groups, dementia and Parkinson’s are added to stroke. This age diversity, Steinmetz agrees, “supports the need to think about neurological health and medical care across the lifespan.”

Researchers have also analyzed how the impact of neurological conditions has fluctuated over the last 30 years and have detected significant changes. For example, the years of healthy life lost have increased by more than 90% since 1990 in the case of diabetic neuropathy and have decreased by the same amount in tetanus. But everything has its explanation: the global rise in the incidence of diabetes can explain an increase in its neurological effects and, on the other hand, the authors attribute to systematic vaccination “the substantial decrease in deaths from tetanus throughout the world.” “The promotion and application of folic acid supplementation and the fortification of cereal products contributed to the decrease in the incidence of neural tube defects in countries that have institutionalized this basic public health initiative,” the researchers add.

“Fight for brain health”

Jesús Porta, president of the Spanish Society of Neurology, celebrates the publication of this study, in which he did not participate: “It is very interesting and important for us. Not so much for the day-to-day life of the neurologist, because we already know a lot of the data, but research that shows the years of loss of quality of life due to neurological diseases alerts us that we must fight for brain health.” With this scenario of neurological pathology on the rise, the doctor calls for “health prevention campaigns and structuring the health system so that there is an adequate response.” For example, he says, with specialized units to meet the growing and diverse demand.

Steinmetz also emphasizes this line. “An aging population means more cases of conditions that affect older adults, such as neurodegenerative conditions. “Health systems must anticipate this and ensure that treatment and care systems are in place to handle the increasing burden.” The researcher specifies that “more than 80% of neurological deaths and DALYs occur in low- and middle-income countries” and, despite the fact that these environments have a higher burden of disease, the workforce trained to treat these ailments is “70 times higher” in high-income areas. “This problem needs to be addressed,” she warns.

The authors also focus on preventable risk factors and point out that high blood pressure, smoking or having high blood glucose levels are variables that encourage neurological pathologies, such as stroke or Alzheimer’s. “In 2021, 84% of DALYs associated with stroke were potentially preventable if exposure to 18 identified risk factors was reduced,” the authors summarize. In this sense, Porta points out three healthy living tips that help prevent brain pathologies: ”Physical exercise, adequate sleep rhythms and adequate nutrition,” he lists.