The longer someone has type 2 diabetes, the higher their cardiovascular disease risk, and changes in red blood cells may help explain it, new research suggests.

The study found red blood cells from patients with long-term diabetes harmed blood vessel function, while no such effect was seen in those newly diagnosed.

After seven years of follow-up, the blood cells of people initially diagnosed had developed the same harmful properties.

Zhichao Zhou, associate professor at Karolinska Institutet and lead author, said: “What really stands out in our study is that it is not only the presence of type 2 diabetes that matters, but how long you have had the disease.

“It is only after several years that red blood cells develop a harmful effect on blood vessels.”

Researchers at Karolinska Institutet in Sweden studied animals and patients with type 2 diabetes.

They identified microRNA-210, a small RNA that helps regulate gene activity, as a possible early biomarker of cardiovascular risk.

When its levels were restored in red blood cells, blood vessel function improved.

Eftychia Kontidou, doctoral student and first author, said: “If we can identify which patients are at greatest risk before vascular damage has already occurred, we can also become better at preventing complications.”

The researchers are now investigating whether the biomarker can be used in larger population studies.

Routine vaccines for adults may reduce dementia risk, a review of more than 100 million people suggests.

The research found both flu and shingles vaccines were associated with a lower risk in adults aged 50 and over.

The shingles (herpes zoster) jab was linked to a 24 per cent lower risk of any dementia and a 47 per cent lower risk of Alzheimer’s disease.

A joint Italian-Canadian neuroscience review points to a pattern that public health experts say is hard to ignore, suggesting vaccines against common infections may offer long-term protection against the UK’s leading cause of death.

With an ageing population, about two million people are projected to be living with dementia in the UK by 2050.

Prof Sir Andrew Pollard is director of the Oxford Vaccine Group and former chair of the Joint Committee on Vaccination and Immunisation.

He said: “Vaccines for pneumonia, shingles, and influenza in older adults have been shown to reduce the risk of serious infections and hospitalisation caused by these diseases.

“But studies in the past few years have raised the intriguing possibility that vaccination could also provide a welcome reduction in the risk of dementia, a disease which places a huge burden on society and the NHS.”

A separate large-scale randomised trial in Wales compared shingles vaccines Zostavax and Shingrix to address the “healthy user effect”, where people who get vaccinated tend to be more health-conscious. As both groups were vaccinated, this helped control for that bias.

The results showed those receiving the newer Shingrix vaccine had a substantially lower risk of developing dementia over subsequent years.

Dr Maxime Taquet, clinical lecturer in psychiatry at Oxford, who led that study, said: “The size and nature of this study makes these findings convincing, and should motivate further research.”