Young-Onset Dementia More Prevalent Than Previously Estimated

Abstract

Back to table of contents Previous article Next article Clinical & ResearchFull AccessYoung-Onset Dementia More Prevalent Than Previously EstimatedNick ZagorskiNick ZagorskiSearch for more papers by this authorPublished Online:23 Sep 2021https://doi.org/10.1176/appi.pn.2021.10.16AbstractA meta-analysis of 95 studies from around the world suggests that nearly 4 million adults globally may experience dementia before age 65.Though considered a disease of the elderly, dementia can strike younger adults as well (Alois Alzheimer’s first patient was a woman who began experiencing memory loss and delusions in her 40s). Yet attention to patients with rare young-onset dementia—typically characterized as dementia before age 65—often pales in comparison to that given to the estimated 45 million adults living with late-onset dementia.A large meta-analysis conducted by Sebastian Köhler, Ph.D., an associate professor of psychiatry and neuropsychology at Maastricht University in the Netherlands, and colleagues suggests young-onset dementia may be more common than previously estimated. Making use of data from 95 individual studies encompassing 2.7 million adults in more than 30 countries, the researchers calculated a global prevalence rate of 119.0 cases of young-onset dementia per 100,000 people. This figure is more than double that of previous estimates and equates to about 200,000 cases of young-onset dementia in the United States and nearly 4 million globally.“Although this is higher than previously thought, it is probably an underestimation owing to lack of high-quality data,” senior author Köhler and colleagues wrote in JAMA Neurology. They noted that data on adults under age 50 were sparse, as were data from low- and middle- income countries.The authors also excluded studies that focused on at-risk population groups like patients with HIV, noted Brian Draper, M.D., a conjoint professor of psychiatry at the University of New South Wales in Australia, who specializes in young-onset dementia. “The bulk of dementia research is related to diseases like Alzheimer’s or frontotemporal dementia, but these secondary dementias that arise from other disorders that can impact the brain should not be discounted,” he said. Draper has done a lot of work with alcohol-related dementia, which overlaps with Wernicke-Korsakoff syndrome, a condition in which chronic alcohol use leads to vitamin B deficiency and subsequent neurodegeneration.Draper told Psychiatric News that the reduced attention to secondary dementias is not entirely from scientists or physicians. “There has been pushback from patients and advocacy groups for conditions like HIV to avoid associating these disorders with dementia due to stigma,” he said. As a result, he said, places like alcohol treatment centers do not often provide dementia screening, which contributes to patients slipping through the cracks.“From a personal management and clinical care perspective, it’s imperative to diagnose young-onset dementia as soon as possible,” Draper continued. “By and large, people who develop dementia earlier in life have a faster rate of cognitive decline, yet they live longer with the disease”—a factor that may be due to younger patients having fewer comorbidities at the time of dementia diagnosis.In an editorial that accompanied Köhler’s JAMA Neurology article, David Knopman, M.D., a professor of neurology at the Mayo Clinic, wrote: “Young-onset dementia is a particularly disheartening diagnosis because it affects individuals in their prime years, in the midst of their careers, and while raising families,” he wrote. “Most dementia care is geared for older patients, and as a consequence, services are rarely available to address the needs of someone diagnosed with dementia in their 50s who has dependent children at home and a spouse who must continue working. Understanding the prevalence and incidence of [young-onset dementia] is a first step in addressing this challenge.”In comments to Psychiatric News, Knopman said that the results of the meta-analysis offered an important perspective on the rates of dementia over time and the relative risks in older versus younger adults. Overall, the study suggests that about 3% of all dementia cases in the United States are in adults under age 65. However, most of these cases were in adults aged 55 to 64.“Among the really young, where the burden would be greatest, dementia is exceedingly rare,” Knopman said. In the age range of 30 to 34, for example, Köhler’s meta-analysis calculated a prevalence of 1 case of dementia per 100,000 people. “At that level, routine screening is out of the question,” he said. “So, on a practical level, how can physicians identify a problem they might encounter once a decade?”It’s a pertinent question for psychiatrists, Draper said, since work by him and others has shown that chronic, treatment-resistant depression can be an early symptom of young-onset dementia. “If you have a middle-aged patient with treatment-resistant depression who begins complaining of memory problems, you should entertain [underlying] dementia as a possibility,” he said.Draper noted that Alzheimer’s disease—which is the most common cause of dementia in older adults—is less dominant in young-onset cases. More commonly, younger patients may experience Disorders like frontotemporal dementia and Huntington’s disease are more common. This is why psychiatrists need to look at more than just cognition in younger people, as behavioral (personality changes) and/or physical symptoms (such as gait disturbances) are most likely to emerge first, he said.“There is no specific pattern that can help diagnose patients at an individual level,” Knopman said. “But if physicians keep an open mind that dementia exists before 65, that can help awareness.”Firsthand clinical experience is also valuable, Knopman continued. “Once you have seen one patient with dementia, it helps make future diagnoses much easier. If more clinicians could do a geriatric rotation, that would help diagnosis tremendously.”The meta-analysis was supported by the Gieskes-Strijbis Foundation, Alzheimer Netherlands, and the Dutch Young-Onset Dementia Knowledge Centre. ■“Global Prevalence of Young-Onset Dementia: A Systematic Review and Meta-analysis” is posted here. ISSUES NewArchived