Why is dementia different for women?

Understanding the differences between men and women in their risk of dementia could help scientists develop better treatments. We discuss these differences, as well as why dementia researchers still have a long way to go to fully understand them.

In this blog, we use the term ‘women’ to refer to those born with female sex, including female chromosomes and hormones, rather than gender.

We currently have very little research evidence specific to people with less common gender status, such as transgender or intersex.

Do women have a higher risk of dementia? 

Yes. Women have a greater risk of developing dementia during their lifetime.

In fact, around twice as many women have Alzheimer’s disease – the most common type of dementia – compared to men.

The main reason for this greater risk is because women live longer than men and old age is the biggest risk factor for this disease.

It’s much less clear if men and women of the same age have different levels of dementia risk.

Some studies have suggested that women over 80 years may be more likely to have Alzheimer’s disease than men of the same age. However, up until this age the risk appears to be about the same for both sexes.

Other studies have found no difference in dementia risk between men and women – even in the oldest age groups. So, it’s really not at all clear whether being a woman means that you’re more likely to develop dementia than a man of your age.

This doesn’t necessarily mean that sex isn’t an important factor in understanding dementia risk. It seems quite likely that each sex has a different blend of risk factors.

Why might women have different dementia risk factors?

Over the course of a lifetime, women tend to have very different experiences than men – particularly women from older generations.

Some of these are caused by differences in biology, such as menstruation, pregnancies and menopause.

Others are more related to traditional differences in gender roles, such as education, work and lifestyle. Many of these have an impact on dementia risk.

Two people sit in a cafe with mugs and a teapot

For example, we know that having a full education and opportunities for lifelong mental stimulation helps to delay dementia in old age – something known as ‘cognitive reserve’.

Historically, opportunities to go to university or work for many years in highly-skilled occupations have been less available to women, which has led some scientists to wonder if this might be an important risk factor for women.

Women may also be more severely affected by some risk factors than men.

Genetics

An important example of this is women’s greater risk when they have the ‘ApoE4’ gene variant.

Genes are the second biggest risk factor for dementia.

Nearly two thirds of people with Alzheimer’s disease – the most common types of dementia – have at least one copy of the ApoE4 gene.

Although men and women are just as likely to have the ApoE4 gene variant, its effect on dementia risk seems to be greater in women than it is in men. The reasons for this difference are not fully understood.

However, it could be extremely important for understanding how future medicines for treating dementia might have different levels of effectiveness for men and women.

Brain injury

Traumatic brain injury (TBI) is another dementia risk factor where there may be important differences between the sexes.

Women are more vulnerable to concussion and its long-term effects on the brain. This has led some to call for greater priority to be given to preventing concussion in women’s sport, such as football and rugby.

Sex, menopause and dementia risk

Risks of dementia associated with menopause

A major difference between older men and women is the menopause. This is when levels of sex hormones, such as oestrogen and progesterone, fall dramatically in women during late middle age.

Oestrogen is thought to have a range of protective effects on brain health, including an ability to block some of the harmful effects of substances involved in Alzheimer’s disease.

This has led some researchers to suggest that if a person has more exposure to oestrogen throughout their life, they might be less likely to develop dementia. For example, if they:

  • start periods at a younger age
  • have at least one pregnancy (when levels of oestrogen are greatly increased)
  • start menopause later.

By contrast, a very early menopause caused by surgical treatments for cancer may increase the risk of dementia in later years.

We also now know that most of the diseases causing dementia start developing in the brain around 10-20 years before clinical symptoms show, which for many women is around the time of their menopause.

It’s tempting therefore to connect the loss of this brain-protecting hormone with the start of processes in the brain that ultimately lead to dementia.

However, the relationships between sex, menopause and dementia risk are extremely complex and until recently researchers have not prioritised menopause as an opportunity to learn more about dementia. We need a lot more research before we can draw any firm conclusions.

A group of people sit around a table laughing

Hormone replacement therapy and dementia

The sex hormones oestrogen and progesterone are commonly used as medicines to treat the symptoms of menopause, such as hot flushes, sleep problems, anxiety and brain fog. This is sometimes called ‘hormone replacement therapy’ (HRT).

During the early days of HRT, there was concern that treatment might have health risks for women in later life, including a greater risk of dementia.

One major study from the US initially suggested this might indeed be the case but further studies found no effect or even a protective effect on dementia risk.

Over the last two decades, the way HRT is provided has been made safer and more efficient, so the potential for long-term risks has been greatly reduced.

Now most of the public interest is focused on whether HRT might actually reduce the risk of dementia.

Our dementia advisers are here for you.

Sex and dementia research

The importance of dementia research that can see differences between the sexes

It may surprise most people to find out that the vast majority of experiments and clinical trials carried out by dementia researchers have not been designed to see differences between male and female participants.

This runs all through the research process. Most older studies involving mice used only males and the first phase of some clinical trials also only recruit male human volunteers.

Most of the time there is a good reason for this bias towards male participants.

Experiments involving animals try to control the situation as tightly as possible so that the only difference between groups of animals is the subject of the research – for example, whether they’ve been treated with a drug or not.

We also need to protect younger women who might be pregnant in case a new experimental drug is unsafe for their baby.

However, the wider implications of doing research like this is that we still have a poor understanding of how diseases causing dementia might work differently in females.

Things are slowly improving as scientists start to appreciate the importance of sex differences in dementia research, but it will take a while to catch up.

How to reduce your risk of dementia

Although getting older is the biggest risk factor for dementia, evidence shows there are things you can do to help reduce your own risk. 

Find out more

35 comments

Obviously a lot of factors that need to be controlled for and investigated. Some of the data analysis is too crude e.g. the number of children doesn’t factor in the number of years on the pill, miscarriages etc which will also change the Oestrogen levels and maybe even if you breastfed for over a year. But the sleep thing is really interesting as snoring husbands have a much bigger and longer impact than pregnancy or menopause, shitty as the later is. I wonder whether that is being taken into account or whether it’s too politically incorrect to raise it ?

What about B12 and Pernicious Anemia? A lot of study is now been seen showing that low levels of Iron and B12 over your life time effects neurology. One of the first signs of Pernicious Anemia is what they call “brain fog”. Women suffer higher instances of Iron and B12 Anemia than men. Is there not something in this? If so how easy would it be to make sure your B12 levels are high and not deficient.

With research suggesting that sleep plays an important role in flushing the brain of harmful waste products such as amyloid beta which are associated with dementia, could the prolonged lack of sleep associated with pregnancy and the menopause be a contributing factor?

Why do more women than men get AZ DM? it makes more sense biologically if the male and female difference in fat to muscle protein is considered, because I suggest what happens in the AZ DM progression is much the same as what happens when faced with famine starvation or as in a diabetic coma the body uses up its fat stores before using muscle protein.

It is known for example that mid life obesity is a risk indicator yet when AZ DM is diagnosed it is more often in later life a few years after the person has become very thin due to weight loss, this is thought to be because a hormone called Leptin is to low.
Here the fact that most of the body s fatty cholesterol is stored in the brain says to me the body is using up that fat reserve up as well as its body fat before it begins to use the body s muscle protein.
But lets not forget AZ DM is not just about the body s hormones and metabolism its about the person who can slowly fade away before your eyes..the latest health and well being advise is that changing our lifestyle will minimize the risk by about 30% which means the usual diet and exercise changes, and some now argue that because AZ DM risk is higher among the less well educated more education will statistically protect you.
Now lets also consider the late 20th century Nuns study which found on autopsy that those Nuns that had the unmistakably loss of brain mass including its cholesterol content, were able to function normally within the family orientated ethos of the organisation, why? because they were valued as human beings and not as just a collection of hormones and that I believe is what makes all the difference for the quality of life even if AZ DM does visit your family. Hate the disease but love the person.
True enough those Nuns were well read people but more importantly they felt loved and valued for who they were not how much they had learnt and that is a powerful motivation.

Not everyone fits the pattern of poor education, deprived up bringing, bad housing, menial job and it is quite difficult to read those descriptions especially when you are getting to grips with Alzheimers.
My husband was very well educated, good housing & food, never smoked, alcohol in moderation with a very responsible job requiring use of brain.

My hypothesis is that more women have dementia then men in the traditional generation ( age 75 to 85 ). Because of the mental abuse they took for 50 years of there life from there husbands. Wish there could be a study on this. No one in my moms family had dementia. She has it and took mental ( no physical abuse) from my dad for 60 years.

My mother recently was diagnosed with sun down dementia. I have several other friends whose mothers are also going thru this same thing as I am with my mom. I was wondering is there any studies that show if you have a hysterectomy before the age of 50 that it can lead to dementia.

My mum died of Lewy Body dementia 2014. Like Claire White’s mum she was a healthy person. Low BP, good BMI (underweight if anything) ate fish. No history of diagnosed mental illness except PND 50 years previously. Generally happy disposition. She could be histrionic at times and spent a considerable time in hospital as a child which could have affected her mental health and attachment in relationships. She had TB in her spine as a child. She had insomnia throughout her life known to be ironing in the early hours. I’d like to see more research linking insomnia, previous life history, diseases in childhood especially nervous system to dementia.

I feel there is a link with anxiety/depression in earlier life that increases the risk of having dementia later in life. A bit like brain overload & eventually something that is a big worry will trigger the Dementia. My Mum had a very healthy lifestyle with no medical problems apart from post natal depression (prescribed valium) after her second child. I believe she suffered from anxiety but it was not diagnosed. Her Alzheimer's was diagnosed at the age of 64 after a trip to New Zealand & 2 extremely worrying life incidents to family. Is the link the drugs given to people who suffer with anxiety & depression, ie. the effect they have on serotonin levels. Or is it the natural make up of the brain & the brain disease is triggered by a life experience? I too suffer from anxiety & have taken Prozac, will be interesting to see what happens to me considering Mum's age when diagnosed with Dementia. I would have thought I would be a prime candidate for research lol.

In the first large-scale epidemiological look at dementia risk and reproductive history, Paola Gilsanz, a scientist with Kaiser Permanente Northern California, and Rachel Whitmer, professor of epidemiology at the University of California, Davis, evaluated data on nearly 15,000 women between the ages of 40 to 55 collected over nearly a decade to find that women with three or more children had a 12 percent lower risk of dementia compared with women who had only one child. (There was a small, but not significant, benefit for having had two kids.)

I thought the information about the differences between women and men in relation to Dementia most interesting. Many thanks. HC