NEW YORK (Reuters Health) Jun 26 – A daily dose of testosterone improves verbal learning and memory in postmenopausal women not taking hormone therapy, according to a new randomized controlled trial.
The findings, along with two previous open-label studies by the same group of researchers that also found improved learning and memory in post-menopausal women given testosterone gel, “provide compelling evidence for the conduct of large-scale clinical studies to further investigate the use of T to prevent memory decline in PM women,” Dr. Susan Davis of Monash University in Melbourne, Australia, and her colleagues conclude.
Dr. Davis presented the results of the 96-patient, single-center study at The Endocrine Society’s Annual Meeting in San Francisco this month.
Dr. Davis and her colleagues randomly assigned 92 healthy postmenopausal women, ages 55 to 65, to receive 0.22 g/day of transdermal testosterone gel (LibiGel) or placebo for 26 weeks.
None of the women had used any type of systemic hormone therapy for the previous 12 months, and none had any characteristics that might impair their cognitive performance.
The researchers used CogState, a computer program that delivers a different randomly allocated test to each study participant for each cognitive domain on each occasion, to measure cognitive function.
At week 26, women in the testosterone group had a significantly greater improvement in their performance on the International Shopping list task, which measures verbal learning and memory, compared to the placebo group. The mean baseline score for both groups was 33.7. The testosterone group showed a 1.57 point greater improvement on their score after adjustment for individual age and baseline score (p=0.037).
Serum total testosterone increased by an average of 1.9 nmol/L in the women treated with testosterone, but did not change in the placebo group.
There were no differences between the two groups at 12 and 26 weeks on the Psychological General Wellbeing Index or any other tests of cognitive function.
Dr. Eef Hogervorst of Loughborough University in Leicestershire, UK, who studies hormones, cognitive function, and dementia but did not take part in Dr. Davis’ study, told Reuters Health, “I would be interested to see how many women had undergone surgical menopause, as this group seems to benefit most in the short term. However what we really need is longer studies. Much more research needs to be done before we can really establish risks and benefits.”
Dr. Marika Moller of the Karolinska Institutet in Stockholm, who has studied the effects of testosterone plus estrogen on cognitive function but did not take part in the current study, commented by email to Reuters Health that “only few studies have investigated testosterone effect on cognition in women, and results have not been conclusive.”
In her own research, Dr. Moller has found that adding testosterone to estrogen treatment had a negative effect on immediate verbal memory in women with surgically induced menopause. A larger randomized trial of testosterone for postmenopausal cognitive function would be “of interest,” she added.
BioSante Pharmaceuticals, which makes LibiGel, provided a research grant as well as the active medication and placebo used in Dr. Davis’s study.
— Anne Harding