Researchers are studying recovery after bowel cancer treatment in older people, as the REBOUND study looks at ageing changes linked to surgery and care.

The study, Resilience Breakthroughs in Older people Undergoing cancer proceDures, is examining how key “hallmarks of ageing” are affected following bowel cancer treatment in people aged 65 and over.

These are the biological processes that naturally occur as we get older.

The chief investigator and principal investigator of the study, professor Thomas Jackson is professor in geriatric medicine at the University of Birmingham and consultant in geriatric medicine and general internal medicine at University Hospitals Birmingham (UHB).

He said: “This is really important work that couldn’t be done without the support of patients agreeing to be in the study.

“We want to understand how the biology of ageing changes when older people have significant events, such as major surgery, and why some people recover well, and others don’t.

“With this understanding, we can identify ways of improving recovery in everyone and maximising the benefits of cancer treatment.”

Researchers at USB, in collaboration with King’s College London (KCL), are leading the study to understand the factors that influence how well older people recover from cancer treatment and to find ways to keep the body strong.

While age is a known risk factor for developing cancer, treatments such as chemotherapy, immunotherapy (which helps the immune system attack cancer), surgery and radiation therapy can trigger processes in the body that resemble ageing.

By understanding how the body responds to cancer treatment, researchers aim to develop new interventions that could prevent or reduce ageing-related changes and improve the number of years spent in good health. The ultimate goal is to help older people with cancer remain active and continue doing the things that matter most to them.

The study involves analysing DNA for age-related changes, examining gut bacteria from stool samples and assessing changes in blood and fat cells.

Samples will be collected at multiple time points before, during and after surgery.

These biological findings will be compared with tests of memory, thinking, strength and muscle function, alongside information from medical records.

The study aims to recruit 172 participants aged 50 years and older who are scheduled to undergo bowel cancer surgery at UHB, Guy’s and St Thomas’ NHS Foundation Trust and King’s College Hospital NHS Foundation Trust.

The study opened to recruitment in autumn 2024, and to date, 58 patients have been enrolled.

The project is a collaborative effort bringing together clinicians specialising in the care of older people, surgeons and scientists with expertise in ageing and complex data analysis. It is supported by the Dynamic Resilience programme, funded by Wellcome Leap and the Temasek Trust.

Long-term air pollution exposure may raise Alzheimer’s risk mainly through direct effects on the brain, a study of US Medicare records suggests.

The research followed more than 27.8m US Medicare recipients aged 65 and over from 2000 to 2018, comparing estimated pollution exposure with later Alzheimer’s diagnoses.

Researchers focused on PM2.5, very fine particles smaller than 2.5 micrometres that can enter the bloodstream and travel to organs including the brain.

The team, led by Dr Yanling Deng of Emory University in Atlanta, Georgia, found higher PM2.5 exposure was linked to a greater risk of Alzheimer’s disease

The association was slightly stronger among people with a history of stroke, while high blood pressure and depression appeared to make little difference.

Dr Deng said: “Overall, the findings suggest that air pollution contributes to Alzheimer’s disease mostly through direct pathways rather than through other chronic health conditions.’

“However, people with a history of stroke may be especially susceptible to the harmful effects of air pollution on brain health.”

Dr Mark Dallas, associate professor in cellular neuroscience at the University of Reading, who was not involved in the study, said: “This long-term study, which tracked 28m adults, suggests that breathing tiny particles of air pollution may slightly increase the risk of Alzheimer’s disease.

“People who have had a stroke might be somewhat more sensitive to these effects, although the increase in risk remains small.”

“Because the research relies on broad pollution estimates and medical records, there are important limitations, but the findings align with growing evidence that air pollution is a modifiable risk factor for dementia.

“Overall, the study reinforces a simple idea: what we breathe over many years can shape how our brains age.”

Matt Loxham, professor of respiratory biology and toxicology at the University of Southampton, said stroke-related damage to blood vessels in the brain could increase their “leakiness”, potentially making it easier for particles or inflammatory molecules to enter.

The blood-brain barrier is a protective lining that normally helps keep harmful substances out.

“Following a stroke, damage to the blood vessels of the brain may increase the leakiness of the vessels (termed the blood-brain barrier), which could potentially facilitate entry of particles or inflammatory molecules into the brain,” he said.

“Alternatively, it is possible that the injury caused by the stroke may render the brain more susceptible to other effects of inhaled pollution.

“However, the mechanism through which any effect of PM2.5 on Alzheimer’s disease is caused is likely to be complex and multifactorial.

“Indeed, it is notable in this study here that the majority of the association of PM2.5 with Alzheimer’s disease was seen even in individuals without previous history of stroke.

“It might be that the mechanisms through which effects occur are in place in otherwise healthy individuals, but just heightened, or acting on already injured tissue, following stroke.”

Loxham said more work was needed to establish how pollution affects the brain, whether some pollutants are more harmful than others, and who is most at risk.