Complete ascertainment of dementia in the Swedish Twin Registry: the HARMONY study

• Published in: Neurobiology of aging 2005-04, Vol.26 (4), p.439-447
• Main Authors: Gatz, Margaret, Fratiglioni, Laura, Johansson, Boo, Berg, Stig, Mortimer, James A., Reynolds, Chandra A., Fiske, Amy, Pedersen, Nancy L.
• Format: Article
• Language: English
• Subjects: Age Factors; Age of Onset; Aged; Aged, 80 and over; Alzheimer Disease - complications; Alzheimer Disease - epidemiology; Alzheimer Disease - genetics; Alzheimers disease; Alzheimer’s disease; Applied Psychology; Biological and medical sciences; Cognition Disorders - epidemiology; Cognition Disorders - etiology; Cognition Disorders - genetics; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dementia; Dementia - epidemiology; Dementia - etiology; Dementia - genetics; Diseases in Twins - genetics; Elderly; Female; Humans; INTERDISCIPLINARY RESEARCH AREAS; Interviews as Topic - methods; Male; Medical sciences; Medicin och hälsovetenskap; Monozygotic twins; Neurology; Neuropsychological Tests - statistics & numerical data; Older people and ageing; Prevalence; Prevalence twin studies; Registries - statistics & numerical data; Sex Factors; Sweden - epidemiology; Tillämpad psykologi; TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN; Twin Studies as Topic; Twins, Dizygotic; Twins, Monozygotic; Äldre och åldrande
• ISSN: 0197-4580; 1558-1497; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2004.04.004

The purpose of this report is to describe the Study of Dementia in Swedish Twins (known as HARMONY), including procedures for complete ascertainment of all cases of Alzheimer’s disease (AD) and other dementias in 14,435 individuals aged 65 and older from the national Swedish twin registry. Telephone cognitive screening identified 11.5% as positive for cognitive dysfunction. Clinical diagnoses were completed for 1557 individuals, including individuals who screened positive, their twin partners, and a sample of normal controls. Estimated prevalence of dementia ranged from 1.4% for age 65–69 to 29.2% for age 90 and older. Concordance rates for Alzheimer’s disease were 59% for monozygotic twins, 32% for like-sexed, and 24% for unlike-sexed dizygotic twins. Among monozygotic twins where both twins had Alzheimer’s disease, the within pair difference in age of onset ranged from both becoming demented in the same year to 7 years difference in onset.