Early-Onset Dementia: Frequency and Causes Compared to Late-Onset Dementia

Abstract

Background: Research on the epidemiology of dementia has focused on the elderly. Few investigations have studied differences in etiologic frequencies between early-onset dementia (EOD), with onset at an age of less than 65 years old, and the more common late-onset disorder. Objectives: To determine relative frequencies and characteristics of EOD versus late-onset dementia (LOD; age of onset ≧65 years) diagnosed in a large memory disorders program over a 4-year period. Methods: We reviewed medical records, including an extensive neurobehavioral and neurological evaluation, of all patients seen at a large Veteran’s Affairs Medical Center Memory Disorders clinic between 2001 and 2004 and assessed demographic variables, final diagnoses, presence of dementia, and differential diagnosis of dementing illnesses. Results: Among 1,683 patients presenting for evaluation of an acquired decline in memory or cognition, 948 (56%) met established clinical criteria for a dementing illness. About 30% (n = 278) of these had an age of onset of <65 years, compared to 670 with LOD. Patients were predominantly male (98%). Compared to the late-onset group, the EOD patients were less severely impaired on presentation, but they did not differ in gender distribution or educational background. The EOD group had significantly more dementia attributed to traumatic brain injury, alcohol, human immunodeficiency virus (HIV), and frontotemporal lobar degeneration compared to the LOD patients. In contrast, the LOD group had significantly more Alzheimer’s disease compared to the EOD group. Conclusions: This study, conducted at a Veterans Affairs Hospital, is the largest series to date on EOD, and found a previously unexpectedly large number of patients below the age of 65 with cognitive deficits and impaired functioning consequent to head trauma, alcohol abuse, and HIV. These findings highlight the differential distribution and importance of preventable causes of dementia in the young.

The Accurate Diagnosis of Early-Onset Dementia

“…Recent clinical reports indicate a significant proportion of EOD patients compared to LOD patients [1,4,5]. Among 948 U.S. veterans, 278 (30%) had EOD [1], and, among 619 patients in England, the proportion of patients with EOD was 28.6% [4]. In another report of 311 patients in Brazil, the proportion of patients with EOD was a high of 46.6% [5].…”

Mutations inTREM2lead to pure early-onset dementia without bone cysts

“…Its prevalence increases exponentially with age, ranging from 67 to 81 per 100, 000 in 45 to 65 year-olds [Harvey et al, 2003;McMurtray et al, 2006] and reaching 18.1% in those aged 85 and older [Krishnan et al, 2005]. Of all the dementias, Alzheimer's disease (AD) is the most common [Kuller, 2007], and patients with AD have been extensively studied.…”

Når demens rammer unge

“…Det kliniske bildet varierer i større grad enn det gjør hos eldre (4). Dette gjelder typer som frontotemporal demens, lewylegemedemens, alkoholrelatert demens, demens etter hodetraume, demens ved Parkinsons sykdom samt sjeldne typer som demens ved Creutzfeldt-Jakobs sykdom, aids, Huntingtons sykdom og multippel sklerose (5). Frontotemporal demens er vanligste form hos pasienter under 50 år (2).…”