Is estrogen protective against risk of brain shrinkage?
USA: A recent study has revealed an association between more estrogen exposure over the lifetime to greater brain volumes and fewer indicators of brain disease on brain scans in midlife. Reproductive history events signaling more estrogen exposure include longer reproductive span, pre-menopausal status, use of hormonal therapy (HT) and hormonal contraceptives (HC), and a higher number of children. The study was published in Neurology, the medical journal of the American Academy of Neurology on November 3, 2021.
"We found that a number of ways a woman is exposed to estrogen—not having reached menopause, having more total reproductive years, having a higher number of children, using menopause hormone therapy or hormonal contraceptives—were associated with larger gray matter volumes in midlife," said author Lisa Mosconi, of Weill Cornell Medicine in New York, N.Y.
The study was conducted with an objective to examine associations between indicators of estrogen exposure from women's reproductive history and brain MRI biomarkers of Alzheimer's disease (AD) in midlife.
For this purpose, the researchers evaluated 99 cognitively normal women ages 52+6 years, and 29 men ages 52+7 years, with reproductive history data, neuropsychological testing, and volumetric MRI scans. Multiple regressions were used to examine associations between reproductive history indicators, voxel-wise gray matter volume (GMV), memory and global cognition scores, adjusting for demographics and midlife health indicators.
Exposure variables were menopause status, age at menarche, reproductive span, age at menopause, number of children, hysterectomy status, and pregnancies, use of menopause hormonal therapy, and hormonal contraceptives.
The study revealed the following findings:
- All menopausal groups exhibited lower GMV in AD-vulnerable regions as compared to men, with peri-menopausal and post-menopausal groups also exhibiting lower GMV in temporal cortex as compared to the pre-menopausal group.
- Reproductive span, number of children and pregnancies, use of HT and HC were positively associated with GMV, chiefly in temporal cortex, frontal cortex, and precuneus, independent of age, APOE-4 status, and midlife health indicators.
- Although reproductive history indicators were not directly associated with cognitive measures, GMV in temporal regions was positively associated with memory and global cognition scores.
"Further studies are needed to elucidate sex-specific biological pathways through which reproductive history influences cognitive aging and AD-risk," the authors concluded.
Reference:
Association of Reproductive History With Brain MRI Biomarkers of Dementia Risk in Midlife. Eva Schelbaum, Lacey Loughlin, Steven Jett, Cenai Zang, Grace Jang, Niharika Malviya, Hollie Hristov, Silky Pahlajani, Richard Isaacson, Jonathan P Dyke, Hooman Kamel, Roberta Diaz Brinton, Lisa Mosconi. Neurology Nov 2021, 10.1212/WNL.0000000000012941; DOI: 10.1212/WNL.0000000000012941
