Women are more at risk than men of developing dementia during a crucial 10-year span, between 65 and 75, a study has found.
Previous research has found women have a greater chance of developing Alzheimer’s disease than men – because they’re more likely to carry a genetic fault.
Yet, despite this risky decade for females, overall the current study found no difference in the risk between the sexes across the lifespan of 55 to 85 years old.
The new finding suggests men and women should be assessed for Alzheimer’s at different ages, it is argued.
It emphasises the importance of carrying out more studies on females as ‘women are not little men’, say the researchers.
The finding that women are at increased risk of developing Alzheimer’s between 65 and 75 years old suggests males and females should be assessed for risks at different ages (file photo)
Study co-author Dr Judy Pa, from the Keck School of Medicine of the University of Southern California, said: ‘The bottom line is women are not little men.
‘A lot more research needs to target women because gender-specific variations can be so subtle that scientists often miss them. Most research today is ignoring a big part of the equation.’
Key findings
The team of researchers analysed 27 independent studies, featuring data on a total of 57,979 individuals diagnosed with Alzheimer’s from North America and Europe.
Some existing studies linked risk of Alzheimer’s and cognitive decline with menopause, as well as genetic factors, but the current findings show that the critical period when women are most at risk is 10 years after the normal start of menopause.
As with past research, genetics could again explain the findings.
In 1993, it was discovered that people with Alzheimer’s were more likely to carry a variant of a gene called APOE4. Carrying one copy of APOE4 can increase the risk of developing Alzheimer’s four-fold, while two copies can lead to a 10-fold increase in risk.
APOE has a protective effect by carrying cholesterol and supporting brain injury repair in healthy people.
The current research was classifying ‘risk’ as whether individuals carried this gene variant. One fifth of the population is thought to have iy.
In 1997, scientists analysed 40 independent studies and found females with the APOE4 variant were four times more likely to have the disease compared with people with the more common, neutral form of the gene.
However, in men, APOE4 seemed virtually harmless.
Risk factors
Yet Dr Pa says that women should not rely on genetic testing to learn whether or not they will develop the disease.
Exhibiting one or more risk factors, she explains, does not necessarily mean that an individual will get it.
‘There is controversy in terms of whether people should know their APOE status because it is just a risk factor,’ she said.
‘It doesn’t mean you’re going to get Alzheimer’s disease. Even if you carry two copies of [the gene variant], your chances are greatly increased, but you could still live a long life and never have symptoms.
‘Scientists still don’t know what is responsible for the difference in risk between men and women.
‘Researchers need to study women 10, 15 or even 20 years before their most vulnerable period to see if there are any detectable signals to suggest increased risk for Alzheimer’s in 15 years.’
According to Dr. Pa, women who are at an increased risk may be able to reduce it by leading an active life and exercising their cognitive skills.
‘Get more exercise. Work out your mind, especially in old age. Pick up hobbies that are cognitively or physically challenging,’ she said.
‘Reduce processed sugar intake because it’s linked to obesity, which is associated with many chronic diseases.’
The study was published in the journal JAMA Neurology.