Solna [Sweden], 9 September (ANI): During a large study recently at Karolinska Institutet in Sweden, researchers have found a link between ADHD and dementia between generations. The results indicate that parents and grandparents of people with ADHD had a higher risk of dementia than those without ADHD.
The study was published in Alzheimers and Dementia: The Journal of the Alzheimer’s Association.
“The results suggest that there are common genetic and / or environmental contributions to the link between ADHD and dementia. Now we need further studies to understand the underlying mechanisms,” said the study’s first author Le Zhang, a doctoral student at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
ADHD (Attention Deficit Hyperactivity Disorder) is a neurodevelopmental disorder characterized by inattention, impulsivity and hyperactivity. It affects an estimated 3 percent of adults worldwide.
The number of new ADHD diagnoses has increased dramatically in recent decades among increased awareness and knowledge about the disease. However, as the diagnosis is still relatively new, there have only been a limited number of small studies on the development of dementia in people with ADHD, often with conflicting results.
In the current study, the researchers wanted to overcome this by examining the extent to which older generations of individuals with ADHD were diagnosed with dementia. The study looked at more than two million people born in Sweden between 1980 and 2001, of which about 3.2 percent were diagnosed with ADHD. Using national records, the researchers linked these individuals to over five million biological relatives, including parents, grandparents and uncles and aunts, and examined the extent to which these relatives developed dementia.
The researchers found that parents of people with ADHD had a 34 percent higher risk of dementia than parents of people without ADHD. The risk of Alzheimer’s disease, the most common type of dementia, was 55 percent higher in parents of people with ADHD. Individuals with ADHD were more likely to have parents with dementia in the beginning than late.
The researchers note that the absolute risk of dementia was low for the parental cohort; only 0.17 percent of the parents were diagnosed with dementia during the follow-up period.
The association was lower for second-degree relatives of people with ADHD, that is, grandparents and uncles and aunts. For example, grandparents of people with ADHD had a 10 percent risk of dementia compared to grandparents of people without ADHD.
While the study cannot establish a cause-and-effect relationship, the researchers present several potential explanations that can be explored in future research.
“One can imagine that there are undiscovered genetic variants that contribute to both traits or family-related environmental hazards, such as socioeconomic status, which can have an impact on the association,” says Zheng Chang, researcher at the Department of Medical Medicine Epidemiology and Biostatistics at Karolinska The institute, and the last author of the study.
He added, “Another possible explanation is that ADHD increases the risk of physical health conditions, which in turn leads to an increased risk of dementia.” (ANI)