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. Moreover, two-thirds of people diagnosed with AD are women and women seem to have a higher risk of developing dementia during their lifetime compared to men.
A woman reading these statements will certainly ask why women have a higher risk of dementia, and be naturally concerned.
Until recently the difference in risk was attributed to the comparatively longer lifespan of women. But 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 higher 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 tangles in the brain compared to men with the same amount of amyloid. Memory loss and other symptoms of AD are related to the amount of tau tangles in the brain.
Lifetime changes in estrogen levels also 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.
According to the lead researcher of the above study, Ki Woong kim. MD, PhD, from Seoul National University College of Medicine in Korea, extremely high levels of estrogen during pregnancy and the abrupt withdrawal of estrogen after childbirth may be harmful to brain cells and decrease cognitive reserve.
Cognitive reserve is the capacity of the brain to withstand aging-related changes and other insults to the brain. Therefore, lower levels of estrogen, which has a protective effect against neurotoxic amyloid, may increase the risk of AD.
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 multiple children.
If estrogen deficiency drives the degeneration of female brain, would estrogen therapy protect the female brain? The story of estrogen and AD is a complex one of controversy. Recent evidence suggests that estrogen strongly protects women’s brains and reduces cognitive decline before the age of 50, but does so 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.
A landmark 44-year-long study from Gothenburg, Germany, showed that women who were physically fit in mid-life had 90 per cent less risk of developing dementia.
What are the implications of all these research studies? Besides informing us of the relatively higher risk of dementia for women due to multiple reasons, they stipulate actions we can take in consultation with physicians to improve our brain health and reduce our risk of dementia.
Therefore, women with multiple children should have cognitive assessment regularly in late life. All women can adopt preventative strategies against AD including regular exercise to improve fitness, life-long learning to improve cognitive reserve, treat depression promptly, and follow healthy plant-based diet, such as Mediterranean diet. Women, heads up for 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