OVARY removal prior to menopause has been shown to impact brain function later in life, according to recent research conducted using MRI data. This study, led by Michelle Mielke, Wake Forest University, Winston-Salem, North Carolina, USA, found that women who undergo premenopausal bilateral oophorectomy (PBO) have reduced white matter integrity in multiple regions of the brain in later life.
Previous research has addressed the link between having both ovaries removed before natural menopause and sudden endocrine dysfunction, which in turn can increase the risk of cognitive impairment and dementia. Few studies, however, have utilised neuroimaging to understand the underlying factors of this relationship.
The researchers used MRI diffusion tensor imaging (DTI), which generates images from the diffusion of water molecules to generate contrast in images. They obtained MR brain images on a 3-tesla scanner with an eight-channel phase array coil between 2011 and 2020 and acquired DTI scans using a single-shot echo-planar imaging sequence with an isotropic resolution of 2.7 mm. The study included data from 1,011 women. Of this group, 22 women had PBO before age 40, 43 had PBO between the ages of 40 and 45, 39 had PBO between the ages of 46 and 49. A reference cohort of 907 women who did not undergo PBO at all was used.
Mielke and team found that women who underwent PBO before age 40 had significantly lower fractional anisotropy compared with other women in the study in the following brain areas: anterior corona radiata (b = -0.39, p = 0.02); genu of the corpus callosum (b = -0.37, p = 0.05); inferior fronto-occipital fasciculus (b = −0.60, p = 0.005); inferior frontal white matter (b = -0.48, p = 0.007); superior occipital (b = -0.41, p = 0.04); and superior temporal white matter (b = -0.48, p = 0.02). No differences were reported in fractional anisotropy or mean diffusivity white matter integrity for women who had the procedure between the ages of 40 and 44 compared with the reference cohort. However, women who underwent PBO between the ages of 45 and 49 had lower frontal anisotropy in the following white matter regions compared to the reference group: interior occipital (b = -0.43, p = 0.006); middle frontal (b = -0.35, p = 0.02); posterior thalamic radiation (b = -0.31, p = 0.04); supramarginal (b = -0.33, p = 0.03); and superior occipital (b = -0.31, p = 0.04). Women who underwent PBO between the ages of 45 and 49 had higher mean diffusivity in the middle frontal (b = 0.28, p = 0.045), retro-lenticular part of the internal capsule (b = 0.35, p = 0.02), superior occipital (b = 0.41, p = 0.007), and superior temporal (b = 0.29, p = 0.047) white matter regions.
Though the researchers called for further studies with larger sample sizes, this research has shed light on the impact of ovary removal on brain regulation.
Victoria Antoniou, EMJ
Reference
Mielke MM et al. Premenopausal bilateral oophorectomy and brain white matter brain integrity in later-life. Alzheimers Dement. 2024;DOI:10.1002/alz.13852.
