Two thirds of dementia sufferers in Germany are female. A study now provides a new explanation for why women are more likely to develop Alzheimer’s than men.

In Germany, 1.8 million people are currently suffering from dementia – including 1.2 million women and 600,000 men. The number of cases worldwide is increasing by around 440,000 every year – and the trend is rising. According to a study by the World Health Organization (WHO), the number of dementia cases worldwide will increase by around 40 percent by 2030. The reason for this: demographic change and the changing lifestyle factors of modern society.

It has long been known that women suffer from dementia much more frequently than men. But why is it that two thirds of those affected by Alzheimer’s in Germany are female? It has long been assumed that the cause of the higher risk of disease is the longer life expectancy of women. On average, women live four to five years longer than men. Studies that calculate out the longer lifespan refute the hypothesis.

Research now assumes hormonal differences between the sexes, which could cause the increased risk of disease in females. A new Chinese study now provides another explanation that takes up the hypothesis mentioned. As the scientists write in their research report, a change in a specific protein in the brain could cause dementia to develop.

As part of the research, the research team examined ten brains each from deceased women and men who had Alzheimer’s disease, as well as from test subjects who had no proven Alzheimer’s disease. They identified a difference in the occurrence of a specific protein that is of great importance for the body’s immune system.

Specifically, it is a mutation of the C3 protein, which the researchers found significantly more frequently in the female subjects than in the women and men examined without Alzheimer’s. “These differences may reflect the fact that the disease is almost twice as common in women as in men,” the study authors write.

The C3 protein is part of the innate immune system and can identify harmful pathogens in the human body. If the C3 changes, it can promote the death of nerve cells in the brain by activating defense cells that erroneously destroy intact synapses as well.

The link between C3 and dementia is not new, but the identified gender difference is. The researchers suspect “genetic and hormonal factors” in women that can favor the mutation of the C3 protein.

The change in the C3 protein can be attributed to the female estrogen level, which in turn falls significantly with increasing age during the menopause. However, as the researchers describe, the female estrogen level is responsible for protecting endogenous proteins such as C3. If the protection decreases, the risk increases that the protein will be modified – and malfunction.

The effect of estrogen levels on the risk of Alzheimer’s has already been examined in several studies. However, it is still controversial whether hormone replacement therapy can reduce the risk of Alzheimer’s. Studies show that the time at which the artificial hormones are taken should have an effect on their effectiveness. As the Federal Center for Health Education (bZgA) writes, hormone replacement therapy that begins shortly after menstruation has stopped can have a positive effect on the risk of disease. Late hormone therapy can even increase the risk of Alzheimer’s.

In addition to hormonal risk factors, other aspects can also explain the higher risk of disease in women. These include:

In principle, the factors also increase the risk of Alzheimer’s in men, but according to studies in women they seem to have a greater effect on cognitive decline.

In any case, the findings of the new study can help in the future to identify and treat dementia at an early stage. So far, the disease has been considered incurable, but the course of the disease can be alleviated – provided that treatment is started as early as possible.

There are some risk factors that you can actively prevent:

You can find out more about the risks and how you can prevent them here.