Multiple Surgeries May Contribute to Cognitive Decline in Older Adults

Multiple surgeries could lead to cognitive decline, according to a study from the University of Sydney, using data from the UK Biobank to analyze half a million patients aged 40 to 69 and followed for 20 years by brain scans, cognitive tests and medical records.

Many families recount how repeated surgeries and hospitalizations have worsened their elderly loved ones’ reaction times and memory. Now a study led by the University of Sydney has found that multiple surgeries have a small effect on memory, reaction time, task switching and problem solving in older patients with each surgery additional.

The study also found that brain MRI scans of people who had surgery also showed physical differences in areas of the brain responsible for memory.

This is the first study of its kind to investigate the impact of multiple complex surgical procedures on brain health, using brain imaging techniques such as MRI in a large population.

The international team looked at data from almost half a million adults aged 40 to 69 in the UK who had surgical procedures, ranging from day surgery to heart bypasses, excluding diagnostic procedures and neurosurgery.

As part of the study, patients then underwent brain MRI and cognitive function tests to detect signs of neurodegeneration.

The study found that with each additional surgery, patients’ overall reaction time slowed by 0⋅3 milliseconds. Cognitive flexibility, problem solving, and the ability to remember pictures and numbers also declined with each additional surgery.

People who had surgery were also found to have smaller hippocampus, the area of ​​the brain responsible for memory and learning. They also had more signs of brain damage associated with blocked blood vessels, compared to those who did not have repeated surgeries.

“The results suggest that cognitive decline by surgery may appear small, but these neurodegenerative changes and losses really start to add up after multiple surgeries,” says lead researcher Dr. Jennifer Taylor, of the Faculty of Medicine and of Health at the University of Sydney.

“We found that surgical interventions are on average safe, but the burden of multiple surgeries on the brain health of older patients should not be underestimated.”

“This reminds healthcare professionals to consider all treatment options and use caution when recommending major surgery to older, more vulnerable patients. If surgery is the best or only treatment option, Patients should be reassured that the cognitive damage from each surgical procedure is small on average, careful attention in perioperative care is needed to prioritize brain health and recovery.

Published in The Lancet: healthy longevityResearchers examined the impact of surgical and medical hospitalizations on cognition, using a large sample of British adults from the UK Biobank from 2006 to 2023.

UK Biobank is the world’s most comprehensive health data source available for research, hosting a large and constantly growing dataset of biological, health and lifestyle information collected over 15 years from a half a million British volunteers.

Data was pooled from 46,706 people, all of whom underwent detailed magnetic resonance imaging (MRI) and cognitive testing.

Participants were tested on their reaction time, memory and ability to think flexibly, by answering a series of linguistic and mathematical questions.

This study continues the work of the same research team that previously found that major surgical procedures (including cardiac, thoracic, vascular, and intracranial surgeries) and hospitalizations were associated with cognitive decline in older patients.

The researchers say future work should focus on understanding the inner biological workings of neurodegeneration. One hypothesis suggests that inflammation may be behind delayed cognitive recovery after surgery, and understanding how this leads to brain damage will be a key next step.

“This paper represents a critical milestone for our field, defining the importance of research into perioperative brain health. We are already testing potential therapies in clinical trials as we strive to advance anesthesia and safe perioperative care,” said lead author Professor Robert Sanders from the University of Sydney and Royal Prince Alfred Hospital.