Understanding the Gender Gap in Alzheimer’s Disease

It’s notable that nearly two-thirds of Americans with Alzheimer’s disease are women, and they tend to experience a quicker cognitive decline than men. The reasons for this significant gender disparity have remained somewhat elusive—until recently.

Research spearheaded by Dr. Farida Sohrabji, a professor and director of the Women’s Health in Neuroscience Program at Texas A&M University, has shed light on how biological sex influences stroke risk in older women. This risk plays a critical role in the onset and progression of dementia.

Dr. Sohrabji noted, “Women, particularly after the age of 50, are more likely to have strokes compared to men, especially severe ones. This dramatically increases their risk for cognitive impairment and dementia and is crucial for the future of drug development and personalized medicine.”

A Shift Toward Personalized Treatment

Her findings align with a growing movement toward precision medicine, which customizes medical care based on individual traits like biological sex.

“The same treatments might not work equally well for both men and women,” Sohrabji pointed out. “Even if the diagnosis is identical, the brain’s response to treatments can differ by sex.”

This information is particularly significant for Alzheimer’s care, since women constitute the majority of patients. In fact, for women over 60, the likelihood of developing Alzheimer’s is nearly double that of developing breast cancer.

“We already tailor treatments for some cancers,” she mentioned. “It’s essential that we apply the same personalized approach to stroke and dementia, which I believe will result in better outcomes overall.”

Dr. Sohrabji’s laboratory has been investigating why women are more heavily impacted by dementia and Alzheimer’s disease.

A key finding relates to hormonal changes during menopause. The decline in estrogen levels makes women’s brains more susceptible to inflammation, damage, and ultimately, stroke—factors linked to dementia and Alzheimer’s risk.

“We discovered that estrogen seems to offer protection against strokes,” she said. “In fact, in experiments where ovaries were removed, the outcomes from strokes worsened, but these were mitigated with estrogen treatment.”

Yet, the evidence is not straightforward, and the relationship can be complicated.

“When we repeated our study using estrogen replacement to see if it would offer protection to older female models, we were surprised to find it did not,” Sohrabji explained. “Estrogen turned out to be toxic, leading to more severe loss of brain tissue and long-term neurodegeneration.”

Exploring New Therapies for Women

In light of these intricate results, Sohrabji and her team began looking into whether a small peptide called IGF-1 (insulin-like growth factor), when combined with estrogen therapy, could enhance outcomes for middle-aged female models. Their findings were eye-opening.

This combination not only reversed the harmful effects typically associated with estrogen in older groups but subsequent studies indicated that IGF-1 alone could significantly improve stroke outcomes.

“When subjects received both estrogen and IGF-1, we observed clear neuroprotective effects,” Sohrabji stated. “IGF-1 treatment emerged as one of the most protective compounds we’ve ever tested.”

Additionally, the researchers examined a small, non-coding RNA molecule and found striking results. The administration of this agent not only protected brain tissue but also significantly reduced signs of long-term cognitive decline.

“Our findings indicate that this agent played a protective role, especially effective in older female subjects compared to similarly aged males,” Sohrabji noted.

The Importance of Recognizing Gender Differences in Research

Sohrabji’s studies highlight a much-needed transition from generic treatments to targeted therapies, aligning with the increasing advocacy within neuroscience and medicine for recognizing sex differences.

“These differences are substantial and have real implications,” she asserted. “It’s part of the reason why women carry a heavier burden when it comes to chronic illnesses like dementia and Alzheimer’s.”

By promoting research focused on sex-specific needs, Sohrabji is paving the way for a future where the challenges of Alzheimer’s are lessened for women and where overall health improves.

“As a basic scientist, my personal passion lies in enhancing human health and addressing critical issues,” she expressed.