Motherhood and a later menopause could reduce the risk of women developing dementia.
A woman with no children is 18 per cent more likely to be diagnosed with dementia than a mother-of-two, a study of more than half a million people has found.
Dementia is also 32 per cent more likely in a woman who naturally enters the menopause at the age of 47, compared to one whose menopause comes later at the age of 50.
Pregnancy and longer child-bearing years before the menopause could help to ward off dementia by exposing a woman to more oestrogen within her lifetime.
The hormone, at the right level in the body, can help to protect the brain.
That could explain an additional finding that women are 20 per cent less likely to develop dementia if they have previously taken the contraceptive pill.
Women who go through menopause early are more likely to get dementia, a study by the George Institute for Global Health headquartered in Australia claimed today
The pill, which alters hormone levels, may also be good for the brain.
Researchers looked at around 273,000 women and 229,000 men aged 40 to 69, from the UK, who were followed up for almost 12 years on average to see if they developed dementia.
The study set out to look specifically at women, who are more likely to get dementia than men and make up two-thirds of dementia deaths.
Researchers looked at the role of ‘reproductive factors’ like their age when they started the menopause, had a baby or went through puberty.
Jessica Gong, who led the study from the George Institute for Global Health in Australia, said: ‘While the risk of developing dementia increases with age, we don’t yet know whether the higher rates seen in women are simply because they live longer.
‘But it’s possible that female-specific reproductive factors may be able to explain some of the sex differences.’
Starting puberty earlier in life was linked to a reduced risk of getting dementia in the study findings.
A woman who reported getting her first period after the age of 14, compared to one who had it aged 13, was almost a fifth more likely to develop dementia.
That could be because of the oestrogen needed to produce an egg every month after going through puberty.
Starting this monthly cycle earlier could mean a longer lifetime of exposure to oestrogen, with its potentially beneficial effect on the brain.
This is also likely to be the reason that women who went through the menopause, at the age of 47 were at higher risk of dementia than those who entered the menopause aged 50.
On average, women go through the menopause between the age of 45 and 55, and every year later it comes, the more oestrogen they may have to protect their brain.
Among the people analysed by researchers, who were part of the UK Biobank study, 1,866 women developed dementia, as did 2,202 men.
Women who had been pregnant were 15 per cent less likely than those who had never been pregnant to get dementia.
But a similar reduced risk in men with children suggests this finding is not all about hormones in the body.
Having a family may simply help to keep parents’ brains active and ward off dementia.
However the results suggest you can have too much of a good thing, with much larger families linked to a higher risk of dementia.
Women with four children, compared to those with only two, had a 14 per cent higher likelihood of getting dementia.
Men with four children had 26 per cent higher odds of getting dementia, compared to those with two children.
The study authors suggest too many children may lead to stress and financial hardship, which is not good for brain health.
The research, published in the journal PLOS Medicine, found no link between women taking hormone replacement therapy (HRT) and dementia, despite this topping up oestrogen in the body.
Having had a hysterectomy, especially if a woman also had her ovaries removed, was associated with a higher risk of getting dementia or dying from it, but this was only a significant factor for women from poorer socioeconomic groups.
The study results were based on women reporting life events like their age of puberty and menopause, which they may not have remembered accurately.
But it shows hormones and life events may reduce people’s risk of dementia, and that having children may be good for both men and women.
WHAT IS DEMENTIA? THE KILLER DISEASE THAT ROBS SUFFERERS OF THEIR MEMORIES
A GLOBAL CONCERN
Dementia is an umbrella term used to describe a range of progressive neurological disorders (those affecting the brain) which impact memory, thinking and behaviour.
There are many different types of dementia, of which Alzheimer’s disease is the most common.
Some people may have a combination of types of dementia.
Regardless of which type is diagnosed, each person will experience their dementia in their own unique way.
Dementia is a global concern but it is most often seen in wealthier countries, where people are likely to live into very old age.
HOW MANY PEOPLE ARE AFFECTED?
The Alzheimer’s Society reports there are more than 850,000 people living with dementia in the UK today, of which more than 500,000 have Alzheimer’s.
It is estimated that the number of people living with dementia in the UK by 2025 will rise to over 1 million.
In the US, it’s estimated there are 5.5 million Alzheimer’s sufferers. A similar percentage rise is expected in the coming years.
As a person’s age increases, so does the risk of them developing dementia.
Rates of diagnosis are improving but many people with dementia are thought to still be undiagnosed.
IS THERE A CURE?
Currently there is no cure for dementia.
But new drugs can slow down its progression and the earlier it is spotted the more effective treatments are.
Source: Alzheimer’s Society