Longitudinal assessment of serum free testosterone concentration predicts memory performance and cognitive status in elderly men.
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.
Moffat
Scott D
SD
Laboratory of Personality and Cognition, Gerontology Research Center, National Institute on Aging/National Institutes of Health, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
Zonderman
Alan B
AB
Metter
E Jeffrey
EJ
Blackman
Marc R
MR
Harman
S Mitchell
SM
Resnick
Susan M
SM
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
D012738:Sex Hormone-Binding Globulin; D013739:Testosterone