Complete ascertainment of dementia in the Swedish Twin Registry: the HARMONY study.
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.
Gatz
Margaret
M
Department of Psychology, University of Southern California, 3620 McClintock Avenue, Los Angeles, CA 90089-1061, USA. gatz@usc.edu
Fratiglioni
Laura
L
Johansson
Boo
B
Berg
Stig
S
Mortimer
James A
JA
Reynolds
Chandra A
CA
Fiske
Amy
A
Pedersen
Nancy L
NL
D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000453:epidemiology / Q000235:genetics; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology / Q000235:genetics; D003704:Dementia / Q000453:epidemiology / Q000209:etiology / Q000235:genetics; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D006801:Humans; D007407:Interviews as Topic / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D015995:Prevalence; D012042:Registries / Q000706:statistics & numerical data*; D012737:Sex Factors; D013548:Sweden / Q000453:epidemiology; D018433:Twin Studies as Topic; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic