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TESTOSTERONE SUPPLEMENTATION AND COGNITION: A REVIEW OF THE CURRENT
FINDINGS
Monique Cherrier
Department of Psychiatry and Behavioral Sciences University of Washington,
Seattle, WA 98195
Natural age related declines in testosterone (T) are associated with
decrements in cognitive abilities independent of health status.
Low T levels over time are associated with increased risk for developing
Alzheimer's disease (AD). These findings suggest that men with low
T levels are most at risk for age-related cognitive decline and
AD and therefore most likely to benefit from T supplementation to
prevent the development of AD or age-associated cognitive decline.
Studies in our laboratory as well as others provide support that
both hypogonadal and eugonadal men, and men demonstrate cognitive
improvements from T supplementation for brief treatment periods
(6-12 weeks), when assessed at a supraphysiological or peak level.
However, not all studies have reported beneficial effects of T supplementation.
In addition to behavioral changes, T may reduce further cognitive
decline due to effects on pathophysiological biomarkers related
to AD. Androgens may also have a role in modulating AD onset and
progression in MCI individuals due to interactions with apolipoprotein
E*4 (APOE*4) as androgens protect against the cognitive declines
observed in transgenic APOE mice.
Findings from studies of T supplementation in older men and Alzheimer's
disease and MCI patients and their effects on cognition will be
reviewed with particular emphasis on dose, design and measurement
issues. Findings from our own laboratory will also be discussed,
including the role of estradiol in cognition for men. Finally, the
potential therapeutic benefit and adverse effects of T supplementation
will be reviewed.
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