Women with naturally higher levels of the hormone precursor DHEAS were found to have better cognitive function than women with lower levels, according to a new study appearing in the March issue of the Journal of Clinical Endocrinology & Metabolism (JCEM).
The study revealed that cognitively intact women with higher circulating levels of DHEA (dehydroepiandrosterone) - in the form of DHEA sulfate (DHEAS)—performed better on tests of executive function, concentration, and working memory.
“This study provides the first evidence that DHEAS is favorably associated with cognitive function,” said Dr. Susan Davis of the Monash University in Victoria, Australia, and lead author of the study. “My colleagues and I found that circulating DHEAS was significantly positively associated with a higher score for a test of executive function, and in the areas of simple concentration and working memory higher DHEAS levels were positively associated with higher scores for women with at least 12 years of education.”
DHEA is a steroid precursor, which means that it is converted in the body to steroid hormones such as testosterone and estrogen. It is the most abundant circulating sex steroid in women.
Previous studies suggest that DHEA and DHEAS may have neuroprotective effects. These studies also suggest that the decline in the production of these steroids with healthy aging may contribute to neuronal dysfunction and degeneration, and thus cognitive decline.
Maintenance of cognitive function in elderly women is influenced by a number of health variables, including diabetes, hypertension, and smoking. Other studies have reported association between these factors and progression to dementia in elderly individuals. “In our study we were specifically interested in the associations between cognitive function and DHEAS, social circumstances, and leisure activities,” said Dr. Davis.
For this study, “Endogenous Androgen Levels in Women across the Adult Life Span,” 295 women, ages 21 to 77 (mean age 55), were recruited from an Australian community-based dataset. Each participant underwent a battery of tests known to measure a wide range of cognitive abilities, including verbal, visual, spatial and working memory, attention and concentration, speed, and accuracy. Women were excluded if they reported any health condition that might potentially adversely affect cognitive function.
In addition to the DHEA and DHEAS findings, the study also found that activities such as living with other people, doing crosswords, and playing a musical instrument were positively associated with cognitive performance. Circulating DHEAS levels were not associated in this study with performance on tests of verbal and non-verbal learning and retention or focused attention.
The researchers speculate that there may be a number of explanations for their findings, including direct action of DHEA and DHEAS, DHEAS being a marker of androgen and estrogen production in women, or simply DHEA and DHEAS levels being markers of general good health.
Although DHEA and DHEAS levels decline in both men and women with age, testosterone levels are generally well maintained in men. In contrast, testosterone levels in women are only a fraction of those found naturally in men. This may mean that even small differences in adrenal pre-androgen production may make a substantial difference to a woman's overall androgen profile.
It should be noted that DHEA, which is commonly sold as a dietary supplement in the United States, is not available over the counter in Australia. The researchers stress that they found no evidence that taking a DHEA supplement would be at all beneficial.
Other researchers involved in this study include Sonal M. Shah, Dean P. McKenzie, Jayashri Kulkarni, Sonia L. Davison, and Robin J. Bell, all of the Monash University.
JCEM is a publication of The Endocrine Society.