Due to biological differences, the overall health impacts between men and women vary. On average, men face higher mortality rates compared to women, with deaths from liver disease being 2.1 times higher, HIV/AIDS 2.7 times higher, and suicide 4.1 times higher than for women.

With these differences, women also face unique health issues such as osteoporosis and arthritis. Women are also more susceptible to mental health disorders. Analysis of studies from the US, UK, Europe, Australia, and New Zealand reveals that women are over 40% more likely to experience mental health conditions.

 Women are considered to have a 75% higher risk of depression and approximately 60% more likelihood of experiencing anxiety disorders. This data has been used to explore the differences between men and women in the book The Stressed Sex.

Given the many biological differences between men and women, is dementia more common in women than in men? Since women are more prone to mental disorders, does this affect their cognitive levels and functioning later in life?

Is dementia more common in women?

For years, it has been believed that the higher rates of dementia, particularly Alzheimer's disease, are due to women living longer than men. However, while women may expect a higher average lifespan, this gap is starting to diminish—men’s health seems to be improving, while women’s health is not.

As researchers focused on additional factors, it became apparent that other elements might contribute to longevity. For example, at age 65, women have a 1 in 6 chance of developing Alzheimer’s disease, compared to men who have a 1 in 11 chance.

Of the approximately 5 million Americans living with Alzheimer’s disease, up to 3.2 million are women, making it evident that the rate of dementia is skewed between men and women. Why does this happen? Is there a way to intervene?

Factors Affecting This Difference

As mentioned, age is the most significant risk factor for developing dementia, which means that women are more likely to be affected than men. Researchers are now questioning this logic, as women only live about five years longer than men on average, while Alzheimer’s disease often begins about 20 years before it is diagnosed.

2014, a significant finding related to genetic variants such as ApoE4 was made. This study, published in Neurology, found that this genetic risk factor is less important for women. Currently, ApoE4 is the most potent genetic risk factor for Alzheimer’s disease, so it is interesting to see how men and women differ in their overall risk.

We all carry an ApoE gene with three variants—ApoE2, ApoE3, and ApoE4. Most individuals have two copies of the ApoE3 variant, one from each parent. About 20% of the population carries at least one copy of ApoE4, increasing the risk of Alzheimer’s disease.

When examining the medical records of 8,000 patients, it was found that women with the ApoE4 gene are twice as likely to develop Alzheimer’s disease compared to women without ApoE4. In contrast, men carrying this genetic variant have almost no increased risk compared to men without the ApoE4 gene.

Another report published in the Alzheimer's Journal suggested that there may be a specific pathological mechanism. Studies of younger women found that their mitochondria are protected against amyloid-beta toxicity, producing fewer reactive oxygen species and apoptogenic signals than men.

However, as women age, this advantage is lost due to hormonal changes. Estrogen compounds that protect against such toxicity require estrogenic effects in older women. Nevertheless, clinical trials involving estrogen therapy have so far not achieved effectiveness in treating Alzheimer’s disease.

Gender and Alzheimer’s Disease

Although experts have sought to explain why gender differences occur, many questions remain unanswered. To address these research areas, the Alzheimer’s Association held a conference with leading experts in Alzheimer’s disease and biological sex specialists. This conference discussed three main topics: endocrine factors, lifestyle influences, and underlying biological mechanisms.

Thanks to this advisory group, the Alzheimer’s Association has launched a new grant program called the Sex and Gender in Alzheimer’s (SAGA) program. This program aims to increase knowledge and help researchers explore why nearly 2/3 of the 5 million Americans with Alzheimer’s are women. We will have results in the future.

(From Livewell Group)

Dr. Phan My Hanh (1/7/2018)