Over 30 million people suffer from Alzheimer's disease worldwide, making it the most common form of dementia.

The study, published in the journal Brain, showed that tau and beta-amyloid are two proteins known to aggregate and accumulate in the brain in patients with Alzheimer's. The first protein to aggregate in Alzheimer's is beta-amyloid.

"Tau accumulation rates vary greatly between individuals of the same sex, but in the temporal lobe, which is affected in Alzheimer's disease, we found a 75 per cent higher accumulation rate in women as a group compared to men," said researcher Ruben Smith from the University of Lund.

For the study, the team collected data from three similar cohorts in the US, the project included 209 women and 210 men.

The researchers said that men and women are equally affected by the first disease stages, and the analysis did not show any differences in the accumulation of beta-amyloid. Memory dysfunction arises later, when tau starts to accumulate.

More women than men are affected by memory problems due to Alzheimer's, and it was for tau that the researchers found a higher rate of accumulation in women, they added.

The accumulation of tau is faster in patients who already have a pathological accumulation of beta-amyloid, and are in the early phase of the disease.

The discovery that the accumulation rate of tau is higher in women remained even after adjusting for age and the levels of tau they had at the beginning, the team said.