title: Longitudinal assessment of serum free testosterone concentration predicts memory performance and cognitive status in elderly men.
abstract: Circulating testosterone (T) levels have behavioral and neurological effects in both human and nonhuman species. Both T concentrations and neuropsychological function decrease substantially with age in men. The purpose of this prospective, longitudinal study was to investigate the relationships between age-associated decreases in endogenous serum T and free T concentrations and declines in neuropsychological performance. Participants were volunteers from the Baltimore Longitudinal Study of Aging, aged 50-91 yr at baseline T assessment. Four hundred seven men were followed for an average of 10 yr, with assessments of multiple cognitive domains and contemporaneous determination of serum total T, SHBG, and a free T index (FTI). We administered neuropsychological tests of verbal and visual memory, mental status, visuomotor scanning and attention, verbal knowledge/language, visuospatial ability, and depressive symptomatology. Higher FTI was associated with better scores on visual and verbal memory, visuospatial functioning, and visuomotor scanning and a reduced rate of longitudinal decline in visual memory. Men classified as hypogonadal had significantly lower scores on measures of memory and visuospatial performance and a faster rate of decline in visual memory. No relations between total T or the FTI and measures of verbal knowledge, mental status, or depressive symptoms were observed. These results suggest a possible beneficial relationship between circulating free T concentrations and specific domains of cognitive performance in older men.
authors.affiliation: Laboratory of Personality and Cognition, Gerontology Research Center, National Institute on Aging/National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
authors.forename: Scott D
authors.initials: SD
authors.lastname: Moffat
authors.forename: Alan B
authors.initials: AB
authors.lastname: Zonderman
authors.forename: E Jeffrey
authors.initials: EJ
authors.lastname: Metter
authors.forename: Marc R
authors.initials: MR
authors.lastname: Blackman
authors.forename: S Mitchell
authors.initials: SM
authors.lastname: Harman
authors.forename: Susan M
authors.initials: SM
authors.lastname: Resnick
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D003071:Cognition; D006801:Humans; D007802:Language; D008137:Longitudinal Studies; D008297:Male; D008568:Memory; D008875:Middle Aged; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013028:Space Perception; D013739:Testosterone / Q000097:blood*; D014785:Vision, Ocular
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone