Glucocorticoids Alter Brain Volume and White Matter Microstructure

Glucocorticoids are widely prescribed for those struggling with autoimmune and neurological conditions and are considered one of the most prescribed drugs. In a study published in BMJ Open, researchers determined that glucocorticoids altered brain volume minimally and reduced white matter microstructure integrity.

According to a StatPearls textbook, “Glucocorticoids are steroid hormones produced from the cortex of adrenal glands. Glucocorticoids have a pivotal role in the glucose, protein, and fat metabolism of the body. They originate from steroid precursors and are synthesized primarily in the zona fasciculata of the adrenal cortex.”

Glucocorticoids often act as anti-inflammatory, anti-allergic, and immunosuppressive medications. They are used to treat allergies, immunology, and inflammatory disorders. Beyond that, these drugs are also prescribed by endocrinologists for patients suffering from adrenal insufficiency and congenital adrenal hyperplasia.

Well-understood side effects of glucocorticoid use are weight gain, fat redistribution, osteoporosis, osteonecrosis, ocular impairments, hyperglycemia, and more. The goal of the study was to determine the neurological effects of these medications.

Researchers in this study used data from the UK Biobank. The chosen patient population had available magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) data. They also excluded patients with a history of psychiatric disease not associated with glucocorticoid use, those taking psychotropic medications, and those with neurological conditions.

As a measure of white matter integrity, researchers looked at fractional anisotropy and mean diffusivity.

The publication states that fractional anisotropy “represents the directionality of water diffusion through the brain and is a marker of microstructural architecture.”

They found a reduction in fractional anisotropy in inhaled and systemic corticosteroid use. For systemic users, the decline was 0.0037; for inhaled users, the drop was less significant at 0.0023.

“This study shows that both systemic and inhaled glucocorticoids are associated with an apparently widespread reduction in white matter integrity, which may in part underly the neuropsychiatric side effects observed in patients using glucocorticoids. Since these medications are widely used, awareness of these associations is necessary across medical specialties and research into alternative treatment options is warranted,” concluded researchers in the publication.

As research on glucocorticoids progresses, researchers may consider a more in-depth analysis of how these changes come about. Additionally, future research may determine the risk of this change based on each patient.