Affiliations: [a] Western Australian Centre for Health and Ageing, Centre for Medical Research, Western Australian Institute for Medical Research, Australia | [b] School of Medicine and Pharmacology, University of Western Australia, Australia | [c] School of Psychiatry and Clinical Neurosciences, University of Western Australia | [d] Department of Psychiatry, Royal Perth Hospital, Australia | [e] School of Population Health and Clinical Practice, University of Adelaide, Australia | [f] Stroke Unit, Royal Perth Hospital, Australia | [g] PathWest, Department of Biochemistry, Fremantle Hospital, Australia | [h] Department of Endocrinology and Diabetes, Fremantle Hospital, Australia
Correspondence:
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Correspondence to: Zoë Hyde MPH, WA Centre for Health and Ageing (M570), University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia. Tel.: +61 8 9224 2750; Fax: +61 8 9224 2063; E-mail: zhyde@meddent.uwa.edu.au.
Abstract: Elevated levels of gonadotropins have been observed in patients with Alzheimer's disease and have been associated with poorer cognition in women, but not men. The aim of this study was to explore the relationship between gonadotropins and cognition in a cohort of 585 healthy, community-dwelling men aged 70–87 years. Cognitive function was assessed with the California Verbal Learning Test Second Edition (CVLT-II) and the Standardized Mini-Mental State Examination (SMMSE). Testosterone, sex hormone binding globulin, and luteinizing hormone levels were assayed from early morning sera. Free testosterone was calculated using mass action equations. In linear regression analyses, neither total nor free testosterone levels were associated with measures of immediate or delayed recall. Higher levels of luteinizing hormone were associated with poorer performance on a measure of immediate recall (CVLT-II trials 1–5 total score) independent of total and free testosterone levels. The association remained after adjustment for age, educational attainment, and depression. In contrast, only total and free testosterone levels were associated with SMMSE score. These findings suggest a role for both androgens and gonadotropins in differing cognitive domains, and that gonadotropins may influence cognition independent of sex steroids.
Keywords: Cognition, gonadotropins, luteinizing hormone, male aging, memory, testosterone
