Interaction between testosterone and apolipoprotein E epsilon4 status on cognition in healthy older men.

Full Abstract

CONTEXT: Reduced testosterone levels have been implicated as a potential causative factor in cognitive decline with older age. Men who possess the apolipoprotein E (APOE) epsilon4 allele have an increased risk of developing Alzheimer's disease; however, no studies have examined whether the influence of testosterone on cognition in healthy older men may be modulated by this genetic predisposition. OBJECTIVE: The objective of the study was to investigate the association between serum testosterone concentrations and cognitive performance in healthy older men, taking into account APOE epsilon4 status. DESIGN: This was a cross-sectional study conducted from 2003 to 2004. SETTING: The study population consisted of community-dwelling males residing in Perth, Western Australia. PARTICIPANTS: Healthy men over 55 yr, free of cognitive impairment and dementia (n = 45), were included in the study. MAIN OUTCOME MEASURES: Participants had fasting early morning blood samples for testosterone and SHBG and were assessed for mood as well as indices of general cognition, verbal and visual memory, executive functioning, working memory, and attention. RESULTS: There was a significant interaction between calculated free testosterone (FT) and APOE epsilon4 on general cognition (P = 0.01) and executive functioning, working memory, and attention (P < 0.01). Higher levels of FT were associated with better general cognition in non-epsilon4 carriers (P = 0.01). By contrast, in epsilon4 carriers higher FT levels were associated with lower scores on tests of executive functioning, working memory, and attention (P = 0.02). In men at increased risk for Alzheimer's disease, higher testosterone levels were not associated with better cognitive function. CONCLUSIONS: Cross-sectional and prospective studies of testosterone and cognition in older men should take into account APOE epsilon4 status.

Author information

Author/s: Burkhardt, Melanie S (MS); Foster, Jonathan K (JK); Clarnette, Roger M (RM); Chubb, S A Paul (SA); Bruce, David G (DG); Drummond, Peter D (PD); Martins, Ralph N (RN); Yeap, Bu B (BB);

Affiliation: School of Psychology, Murdoch University, Murdoch, Western Australia 6150, Australia.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab), published in United States. (Language: eng)

Reference: 2006-Mar; vol 91 (issue 3) : pp 1168-72

Dates: Created 2006/03/08; Completed 2006/06/07; Revised 2006/11/15;

PMID: 16368754, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.