This Article  • References  • Full text PDF  • Reply to article  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Contact me when this article is cited  Related Content  • Similar articles in this journal  Social Bookmarking   What's this?

A Study of 4000 Twin Pairs

Jason Brandt, PhD; Kathleen A. Welsh, PhD; John C. S. Breitner, MD, MPH; Marshal F. Folstein, MD; Michael Helms, MS; Joe C. Christian, MD, PhD

Arch Neurol. 1993;50(6):599-603.

Abstract
• Objective.
—To determine the contribution of genetic factors to cognitive functioning in older men.

Design.
—Cognitive testing by telephone interview in an epidemiologically defined population.

Participants.
—2077 monozygotic and 2225 dizygotic male twin pairs, all between the ages of 62 and 73 years, recruited from the National Academy of Sciences twin registry.

Main Outcome Measures.
—The Telephone Interview for Cognitive Status—Modified total score and factor scores were analyzed. The Falconer heritability statistic and maximum likelihood estimates of genetic and environmental components were computed.

Results.
—Heritability of the total Telephone Interview for Cognitive Status—Modified score was estimated to be 30%. Shared environmental effects accounted for an additional 18% of the variance; most of this was related to years of education. Of the four cognitive factors derived, the language/attention factor had the highest heritability estimate.

Conclusions.
—Genetic factors and educational achievement together account for almost half of the variance in the cognitive functioning of older men. Studies of the genetics of dementing illnesses need to consider the degree to which cognitive capacities are themselves under genetic control.

Author Affiliations
From the Department of Psychiatry and Alzheimer's Disease Research Center, The Johns Hopkins University School of Medicine, Baltimore, Md (Drs Brandt and Folstein); Department of Psychiatry, Center for the Study of Aging, and Joseph & Kathleen Bryan Alzheimer's Disease Research Center, Duke University Medical Center, Durham, NC (Drs Welsh and Breitner and Mr Helms); and Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis (Dr Christian).

Footnotes
Accepted for publication December 8, 1992.

Reprint requests to Department of Psychiatry and Behavioral Sciences, Meyer 218, The Johns Hopkins Hospital, 600 N Wolfe St, Baltimore, MD 21287-7218 (Dr Brandt).

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

CKD Associates with Cognitive Decline
Khatri et al.
J. Am. Soc. Nephrol. 2009;20:2427-2432.
ABSTRACT | FULL TEXT  

A Review of Telephone-Administered Screening Tests for Dementia Diagnosis
Smith et al.
AM J ALZHEIMERS DIS OTHER DEMEN 2009;24:58-69.
ABSTRACT  

A review of screening tests for cognitive impairment
Cullen et al.
J. Neurol. Neurosurg. Psychiatry 2007;78:790-799.
ABSTRACT | FULL TEXT  

Telephone assessment of cognitive function in adulthood: the Brief Test of Adult Cognition by Telephone
Tun and Lachman
Age Ageing 2006;35:629-632.
FULL TEXT  

Occupational characteristics and cognitive performance among elderly male twins
Potter et al.
Neurology 2006;67:1377-1382.
ABSTRACT | FULL TEXT  

Cognitive performance predicts treatment decisional abilities in mild to moderate dementia
Gurrera et al.
Neurology 2006;66:1367-1372.
ABSTRACT | FULL TEXT  

Telephone screening for amnestic mild cognitive impairment
Lines et al.
Neurology 2003;60:261-266.
ABSTRACT | FULL TEXT  

Intracranial capacity and brain volumes are associated with cognition in healthy elderly men
MacLullich et al.
Neurology 2002;59:169-174.
ABSTRACT | FULL TEXT  

Deficits in Controlled Processing May Predict Dementia: A Twin Study
Andel et al.
Journals of Gerontology Series B: Psychological Sciences and Social Science 2001;56:P347-355.
ABSTRACT | FULL TEXT  

Reliability of the Blessed Telephone Information-Memory-Concentration Test
Kawas et al.
J Geriatr Psychiatry Neurol 1995;8:238-242.
ABSTRACT  

Alzheimer's Disease in the National Academy of Sciences--National Research Council Registry of Aging Twin Veterans: III. Detection of Cases, Longitudinal Results, and Observations on Twin Concordance
Breitner et al.
Arch Neurol 1995;52:763-771.
ABSTRACT  

Lower Cognitive Performance in Normal Older Adult Male Twins Carrying the Apolipoprotein E {varepsilon}4 Allele
Reed et al.
Arch Neurol 1994;51:1189-1192.
ABSTRACT