Seventy-two per cent of people impacted by Alzheimer’s Disease (AD) and related dementias are women. This includes people diagnosed with the dementia and their caregivers. In fact the overall lifetime risk for AD at age 65 is 21.1% for women and 11.6% for men.
Why do women have a higher risk for AD? The obvious reason is the comparatively longer lifespan of women. Researchers suspect that women have an increased biological vulnerability to develop the disease. Recent evidence suggests that women develop the disease at a younger age than men do, with the highest risk in their 50s and 60s.
Some studies have shown that the female brain undergoes massive transition when estrogen level plummets during menopause.
In post-menopausal women glucose utilization in the brain has been found to be only one-quarter of that in younger women and this energy crisis could trigger degeneration.
AD is associated with abnormal deposition of beta amyloid protein outside the brain cells and tau tangles inside the brain cells. It has been observed that women accumulate more tau in their brain compared to men with the same amount of amyloid. Memory loss and other symptoms of AD correlate with the amount of tau in the brain.
Lifetime changes in estrogen levels seem to affect women. According to a recent study women who had five or more completed pregnancies were found to have 1.7 fold higher risk of AD than those who experienced one to four completed pregnancies.
Surprisingly, women who had incomplete pregnancies had about half the level of AD risk than those who were never pregnant.
The extremely high levels of estrogen during pregnancy and its abrupt withdrawal after childbirth may be harmful to brain cells and decrease cognitive reserve – the capacity of the brain to withstand aging-related changes and other insults to the brain.
Previous studies have shown that grey matter volume is reduced in multiple regions after motherhood and these changes to neuroplasticity may have lasting consequences. There could be other psychosocial factors such as the stress of caring for an infant and the demands of raising multiple children.
If estrogen deficiency drives the degeneration of female brain, would estrogen therapy protect the female brain?
The connection between estrogen and brain health is complicated.
Recent evidence suggests that estrogen strongly protects women’s brains and reduces cognitive decline before the age of 50, but only moderately between the ages of 50 and 59, and perhaps becomes harmful and increases cognitive decline at age 60 and after.
Hormone therapy administered shortly after menopause seems to protect the brain, but harms cognition when administered long past menopause. The harmful effects on the brain are more severe among women who have unhealthy levels of metabolic markers – such as high blood pressure, high cholesterol/triglycerides, and high blood sugar.
Are women doomed to develop dementia? Recent studies reiterate that women’s brain health is mostly in their own hands. A landmark 44-year-long study from Gothenburg, Germany, showed that women who were physically fit in mid-life had 90% less risk of developing dementia.
Recent studies show that women who maintained high levels of physical and cognitive activity in midlife had significantly lower risk for dementia than others.
Another study that followed the diet and lifestyle of women from their twenties to their sixties, found that women who adhered strictly to Mediterranean diet throughout adulthood had much better memory and cognitive abilities in late life.
So what steps can women take to ward off dementia?
All women should be aware of their unique risks, and adopt preventative strategies such as engaging in regular exercise (eg. brisk walking) to improve fitness and life-long learning to improve cognitive reserve. They should follow Mediterranean (plant-based) diet, and treat high blood pressure, depression and hearing loss promptly.
Women with multiple children should have cognitive assessment regularly in late life.
I urge all women to work closely with their physician and take charge of their brain health
Padmaja Genesh, who holds a bachelor degree in medicine and surgery as well as a bachelor degree in Gerontology, has spent several years teaching and working with health care agencies. A past resident of Red Deer, and a past board member of Red Deer Golden Circle, she is now a Learning Specialist at the Alzheimer Society of Calgary. Please send your comments to firstname.lastname@example.org.