Is this why more women get Alzheimer’s? Scientists discover men have fewer disease-causing proteins

Is this why women have a higher risk of Alzheimer’s? Scientists discover men have fewer dementia-causing proteins in their brains

  • Massachusetts General Hospital studied the brains of 300 elderly people 
  • They found men had less tau and beta amyloid that trigger Alzheimer’s

Women are more prone to developing rogue proteins in the brain that trigger Alzheimer’s disease, according to new research.

A study of 300 elderly people found men had less tau and beta amyloid that trigger the devastating condition.

When these gather in tangles or clumps, respectively, they destroy neurons – leading to memory loss and confusion.

The chemicals are present in all grey matter and only cause a problem in large amounts.

Now PET (positron emission tomography) scans have shown they are more prevalent in women – even among healthy older individuals.

Even healthy women had more disease-causing tau and beta amyloid, the study found

Lead author Dr Reisa Sperling, of Massachusetts General Hospital, said: ‘Growing evidence suggests women may be at increased risk of certain physiological changes associated with Alzheimer’s disease.’

It could shed fresh light on why around two-in-three dementia sufferers are female. Much of the gender gap has been blamed on age.

The older you are the more likely you are to be struck down – and men typically die sooner.

But many scientists believe it’s not as simple as that – and other mechanisms must be involved.

So the study looked specifically for deposits in the brain of the protein tau, a sign of Alzheimer’s, among cognitively normal participants whose average age was 74.

Dr Sperling, who is Professor of Neurology at Harvard Medical School, said: ‘Women showed more tau in a region of the brain than men, which was associated with individuals with greater amounts of plaque deposits of the beta-amyloid peptide, another marker of Alzheimer’s.’

Previously it was thought there was no difference in the levels of these proteins, or ‘biomarkers’, in men and women with Alzheimer’s disease.

The importance of investigating the differences between the male and female specifics of the disease is becoming increasingly important.

Over the last 20 years, new dementia cases in the UK have dropped by a fifth – driven mostly by a fall in incidence among men over 65.

Experts say this may be because of public health campaigns targeting heart disease and smoking.

Both can cause Alzheimer’s – the most common form of dementia.

As men tend to get heart disease younger and smoke more these campaigns may have had less effect staving off these risk factors for women.

Meanwhile, more women develop depression – which has been linked to the onset of Alzheimer’s.

Removal of the ovaries and pregnancy complications like pre-eclampsia – both of which only effect women – have also been linked to cognitive decline in later life.

Caregiving also may increase the chance of developing dementia. 

Dr Sperling said: ‘These findings support other studies in identifying potential reasons for differences in risk for Alzheimer’s disease between men and women.’

Earlier research has shown women predisposed to Alzheimer’s have elevated levels of tau in their cerebro-spinal fluid compared with men carrying the mutated gene.

The latest study published in JAMA Neurology is the first to identify the same pattern in clinically normal people.

Dr Sperling said: ‘Early tau deposition was elevated in women compared with men in individuals on the Alzheimer’s disease trajectory.

‘These findings lend support to a growing body of literature that exposes a biological underpinning for sex differences in Alzheimer’s disease risk.’

More than 50 million people worldwide are living with dementia with numbers rising quickly.

Globally, experts estimate 75 million people will have it by 2030 – and 131.5 million by 2050.