Skip to main content Accessibility help
×
×
Home

Heritability of an Age-Dependent Categorical Phenotype: Cognitive Dysfunction

  • Chandra A. Reynolds (a1), Amy Fiske (a2), Laura Fratiglioni (a3), Nancy L. Pedersen (a4) and Margaret Gatz (a5)...

Abstract

We investigated the extent to which cognitive dysfunction is shaped by genetic or environmental influences, and whether these factors differ in women and men. All members of the Swedish Twin Registry aged 65 and older were screened by telephone using the TELE, a brief cognitive assessment instrument (Gatz et al., 2002), and the Blessed Dementia Rating Scale (Blessed et al., 1968) from relatives of those who scored poorly on the TELE. Data were available for 4308 pairs where both members responded and 5070 pairs where only one member was alive and participated. To analyze all available data, we used a raw data method extended to ordinal data. As the prevalence of cognitive dysfunction increases with age, we incorporated age-adjusted thresholds. The best fitting model from biometric analyses indicated 35% of the variation in liability to cognitive dysfunction could be explained by heritable influences and the remaining 65% by nonfamilial environmental influences. Differences by gender were not significant. As this is a normative population including cognitively intact individuals, preclinical dementia cases and demented individuals, the relative magnitude of genetic and environmental effects is of particular interest in light of high heritabilities found for dementias such as Alzheimer's disease. The findings emphasize the extent to which research is needed to uncover nonfamilial environmental influences on cognitive dysfunction in later life.

    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Heritability of an Age-Dependent Categorical Phenotype: Cognitive Dysfunction
      Available formats
      ×

      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Heritability of an Age-Dependent Categorical Phenotype: Cognitive Dysfunction
      Available formats
      ×

      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Heritability of an Age-Dependent Categorical Phenotype: Cognitive Dysfunction
      Available formats
      ×

Copyright

Corresponding author

*Address for correspondence: Chandra Reynolds, Department of Psychology, University of California — Riverside, Riverside, CA 92521, USA.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Twin Research and Human Genetics
  • ISSN: 1832-4274
  • EISSN: 1839-2628
  • URL: /core/journals/twin-research-and-human-genetics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed