The purpose of this study was to determine whether the level
of serum total testosterone (TT) was different in cases of
Dementia of the Alzheimers Type (DAT) than in controls.
SETTING AND DESIGN: We included 83 referred DAT cases and
103 cognitively screened volunteers (aged 75±9 years)
from the Oxford Project To Investigate Memory and Ageing.
METHODS: Information was obtained about potential confounds
in the relation of DAT with testosterone, including age, gender,
education, body mass index, smoking, (ab)use of alcohol, diabetes
mellitus, endocrine therapy, and having undergone hysterectomy.
TT was measured in non-fasting serum obtained between 10 and
12 a.m. using a competitive enzyme immunoassay.
RESULTS: Men with DAT (n=39) had lower levels (p =0.005) of
total serum testosterone (TT=14±5 nmol/L) than controls
(n=41, TT=18±6 nmol/L). Lower TT was more likely in
men with DAT, independent of potential confounds (Odds Ratio=0.78,
95% C.I.=0.68 to 0.91). In women there was no difference in
TT levels between cases (n=44) and controls (n=62).
MAIN FINDINGS: Our results suggested that low TT may be a
co-morbid feature of DAT in men. However, low TT levels could
also exacerbate the disease.
CONCLUSIONS: Prospective longitudinal studies should investigate
whether low TT levels precede or follow the onset of DAT (209