US scientists have recently identified a possible genetic link between diabetes and Alzheimer’s disease.

It has been known for some time that people with diabetes have a much higher risk of developing Alzheimer’s, but not why this is so.

Now researchers writing in Genetics say a study of worms has indicated a known Alzheimer’s gene also plays a role in the way insulin is processed.

Dementia experts said more work in humans was now needed.

US scientists have recently identified a possible genetic link between diabetes and Alzheimer's disease

Alzheimer’s is the most common cause of dementia.

There are medications which can slow the progress of the disease, but none that can halt its progress.

A key indication of Alzheimer’s, which can only be seen after death, is the presence of sticky plaques of amyloid protein in decimated portions of patients’ brains.

Scientists have already found mutations in a gene involved in the processing of amyloid protein in Alzheimer’s which run in families.

In this study, a team from the City College of New York looked at a similar gene in the nematode worms (C. elegans).

These worms are often studied because they, perhaps surprisingly, a useful model for human research.

The researchers, led by Prof. Chris Li, found the gene in the worms also affected the insulin pathway – the chemical reactions involved in its production and processing.

Prof. Chris Li said: “People with type 2 diabetes have an increased risk of dementia.

“The insulin pathways are involved in many metabolic processes, including helping to keep the nervous system healthy.”

She said more work was needed to investigate this potential link and its effects further.

Mark Johnston, editor-in-chief of the journal Genetics, said it was “an important discovery”.

“We know there’s a link between Alzheimer’s and diabetes, but until now it was somewhat of a mystery.

“This finding could open new doors for treating and preventing the disease.”