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Taken from WWW.pubmed.gov (testosterone studies)
Clin Endocrinol (Oxf). 2007 Oct 31 [Epub ahead of print]
Bioavailable testosterone is associated with a reduced risk of amnestic mild
cognitive impairment in older men.
Chu LW, Tam S, Lee PW, Wong RL, et al
Division of Geriatric Medicine, Department of Medicine, Queen Mary Hospital, Faculty of Medicine, the University of
Hong Kong, Hong Kong.
Objective: We investigated the risk of amnestic mild cognitive impairment (aMCI) in relation to serum bioavailable
(BT) and total testosterone (TT) levels in older men. Design, setting and subjects A cross-sectional study in an
ambulatory setting, with older men aged 55-93 years with normal cognition, aMCI and Alzheimer's disease (AD).
Measurements Morning serum BT and TT levels were determined. AD was diagnosed by the Neurological and Communicative
Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS-ADRDA) criteria for probable AD
and aMCI by the Petersen criteria.
Results: We recruited 203 Chinese older men (48 aMCI, 66 AD and 89 with normal cognition). Mean serum BT, but not TT,
levels were significantly lower in the aMCI (mean BT +/- SEM 1.06 +/- 0.10 nmol/l) and AD (0.99 +/- 0.08 nmol/l)
groups than in the normal controls (1.82 +/- 0.12 nmol/l) (P < 0.001, one-way anova) with no significant difference
between the aMCI and AD groups. After adjustment for education, age and apolipoprotein E (apoE) genotype, logistic
regression analyses showed that the serum BT level [adjusted odds ratio (OR) = 0.52, 95% confidence interval
(CI) 0.32-0.85] was an independent protective factor for aMCI. For the combined outcome of aMCI and AD, the serum
BT level was an independent protective factor but age and apoE epsilon4 were independent risk factors. There was
no interaction between BT and age.
Conclusions: In older men, serum BT (bioavailable testosterone), but not TT (total testosterone),
levels were associated with a lower risk of aMCI and AD (dementia and Alzheimer’s disease).
PMID: 17973937 [PubMed - as supplied by publisher]
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