Alzheimer’s disease is twice as common in people assigned female at birth than those assigned male at birth. This is mainly due to longer life expectancy, but genetics may also play a role.

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People assigned female at birth appear to be more than twice as likely to get Alzheimer’s disease than people assigned male at birth.

Alzheimer’s is a type of dementia that happens slowly over time. As it progresses, symptoms like memory loss and behavioral changes can disrupt daily life.

Read on to learn more about why Alzheimer’s may be more common in women than men, the outlook for Alzheimer’s across genders, and other risk factors for Alzheimer’s to take into consideration.

The simplest explanation is that females live longer than males on average. Since Alzheimer’s typically affects people as they age, you’re more likely to get Alzheimer’s the longer you live.

But a protein in the brain called tau and the effect of apolipoprotein E (APOE) gene on tau may also play a role.

Age

The National Center for Health Statistics estimated in 2020 that females live an average of 5.4 years longer than males. Women live to be about 80.5 years old, while men live to be about 75.1 years old.

Age is the most evident risk factor for Alzheimer’s. After the age of 65 years, the number of people with Alzheimer’s doubles about every 5 years. This means that the 5 years that females live longer than males means they’re more likely to develop Alzheimer’s.

A 2018 study of the medical records of over 16,000 Swedish adults seems to support this idea. Researchers found that the risk of Alzheimer’s becomes much higher for females than males in their late 70s and early 80s. Since females tend to live longer, their risk continues to increase as they age.

Genes and proteins

Your risk for Alzheimer’s has a close link to a protein in your brain called tau. Doctors can test for tau by analyzing your spinal fluid.

When tau builds up in your brain, it can lead to the development of Alzheimer’s and other types of dementia. And the way certain genes affect tau can increase your risk of Alzheimer’s.

According to a 2019 study, tau tends to start building up in females’ brains earlier than in males. Tau also spreads wider in females’ brains over time.

A 2023 study also identified a role for the APOE gene in how tau affects the brain.

Having a variant of APOE called APOE4 can increase your risk of early tau buildup in your brain. An earlier 2020 review of APOE in people with Alzheimer’s also suggests that females are more likely to carry APOE4 than males.

There’s no clear evidence that the outlook for Alzheimer’s is noticeably different for females or males.

Some research suggests that the effects of stress and female immune system proteins may contribute to higher risk and more severe cases of Alzheimer’s in females, but this research is still inconclusive.

Females also tend to score higher on verbal diagnostic tests for dementia than males. Doctors may miss early signs of Alzheimer’s in females because their diagnostic results don’t always clearly portray their risk.

In addition to sex, gender may also play a role. A 2022 study suggests that inequality in access to proper medical care has the biggest influence on the outlook that women and men face in complications of dementia.

Having inadequate healthcare and experiencing widespread medical gaslighting can keep women from receiving treatment before the disease progresses. Combined with the increased risk for Alzheimer’s with age, the outlook for women with Alzheimer’s as they age may be less favorable than for men.

Other forms of dementia also appear to be more common in females than in males, especially as they reach the age of 80 years and beyond.

A 2020 study suggests that childbirth may play a role in the risk of dementia for females. The more children they have, the higher their risk for all types of dementia — especially for females in Europe and Latin America.

A 2023 study of nearly 30,000 people from 6 continents — 58% of whom were female — illustrates that income level and socioeconomic status may play a significant role in the higher Alzheimer’s risk that females face.

There is limited research on how common Alzheimer’s disease is among people who don’t identify as their sex assigned at birth.

A 2023 study states that people who were transgender or nonbinary had a higher risk of Alzheimer’s later in life than cisgender people. But there isn’t enough research on overall health outcomes in people who are not cisgender, so it’s unclear exactly why the risk of Alzheimer’s is higher in this population.

Researchers have also noted that a better understanding of what causes Alzheimer’s — beyond differences in males and females — may help clarify how age, genes, diet, and lifestyle affect Alzheimer’s risk beyond the gender binary.

Apart from age and gender, other risk factors for Alzheimer’s disease include:

Alzheimer’s appears to affect females more than males. This is because females tend to live longer. They’re also more likely to have a gene variant that can cause tau protein to spread earlier and wider in the brain.

But there’s also a major gap in the research on how inequities in medical care affect early detection and care in women. More research will help understand the differences in Alzheimer’s symptoms between the sexes, making it easier to identify the early signs.