Cortisol Levels Linked to Brain Volume in Elderly

Monitoring cortisol levels in the saliva of elderly patients may help to identify those with cognitive impairment, according to a recent study.

Previous research has shown that depression may increase the risk of dementia, but little data exists on the nature of this relationship. High levels of the stress hormone cortisol have been found in patients with depression, leading researchers to hypothesize that it may have a toxic effect on the hippocampus, affecting memory.
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For their study, researchers evaluated 4244 patients without dementia between the ages 71 and 81 years. Each participant had a cognitive functioning assessment, a 1.5T brain MRI, and had their saliva collected 45 minutes after waking in the morning and at before bed at night.

Researchers used linear regression analysis and adjusted for covariates to estimate the relationship between brain volumes, cortisol levels, and cognitive function.

The study showed that higher volumes of cortisol in the evening were linked to smaller total brain volume (highest vs lowest tertile, –16.0 mL [95% confidence interval (CI), –19.7 to –12.2 mL]).

While researchers observed smaller volumes in all brain regions, they found significantly smaller volumes in gray matter regions than in white matter regions.

Further, researchers discovered that higher levels of evening cortisol were associated with poorer cognitive function.

“Higher levels of morning cortisol were associated with slightly greater normal white matter volume and better processing speed and executive functioning, but not with gray matter volume or with memory performance,” said the study’s authors.

“Understanding these differential associations may aid in developing strategies to reduce the effects of hypothalamic-pituitary-adrenal axis dysfunction on late-life cognitive impairment,” they concluded.

The complete study is published in the August issue of Neurology.

-Michelle Canales

Reference:

Geerlings MI, Sigurdsson S, Eiriksdottir G, et al. Salivary cortisol, brain volumes, and cognition in community-dwelling elderly without dementia. Neurology. 2014 August [epub ahead of print] doi: 10.1212/WNL.0000000000001931.