As people grow older, it is common to notice small changes in memory and thinking. Many families have also observed that older adults sometimes seem more forgetful or slower in their thinking after going through surgery.
A new study led by the University of Sydney now provides strong evidence that repeated surgeries may play a role in these changes.
The research used data from the UK Biobank, one of the largest health databases in the world. It included nearly half a million people aged between 40 and 69.
The researchers followed these participants over a period of about 20 years. They examined medical records, brain scans, and results from thinking and memory tests to better understand how surgeries might affect the brain over time.
Surgery is often necessary to treat serious health conditions and can greatly improve quality of life. However, it also puts stress on the body.
This stress can come from the surgery itself, the use of anesthesia, and the body’s response during recovery. Scientists have long wondered whether repeated exposure to these stresses could have long-term effects on brain health.
In this study, the researchers looked at people who had undergone different types of surgeries. These ranged from simple day procedures to more complex operations such as heart bypass surgery. They did not include brain surgeries or diagnostic procedures, so the focus remained on surgeries that were not directly related to the brain.
After their surgeries, participants completed tests that measured memory, reaction time, and problem-solving ability. Many of them also had brain scans using MRI technology, which allowed researchers to see detailed images of the brain.
The results showed a clear pattern. With each additional surgery, there was a small decline in cognitive performance. Reaction times became slightly slower, and people found it a bit harder to remember information or solve problems.
On average, reaction time slowed by about 0.3 milliseconds per surgery. While this change is very small on its own, it can become more noticeable over time if a person has multiple surgeries.
The brain scans also revealed physical changes. People who had undergone several surgeries tended to have a smaller hippocampus. The hippocampus is a part of the brain that plays a key role in memory and learning. A smaller hippocampus is often linked to memory problems and aging-related brain changes.
In addition, the researchers found more signs of damage related to blood vessels in the brains of people who had multiple surgeries. This type of damage can affect how well different parts of the brain communicate with each other, which may contribute to slower thinking and memory issues.
Dr. Jennifer Taylor, the lead researcher, explained that the effects of each individual surgery are small. However, when surgeries are repeated over many years, these small changes can add up. This is especially important for older adults, who may already be at risk of cognitive decline.
The findings do not mean that people should avoid surgery when it is needed. In many cases, surgery can save lives or greatly improve health. Instead, the study highlights the importance of careful decision-making. Doctors and patients should consider all possible treatment options and weigh the benefits and risks.
When surgery is necessary, steps can be taken to protect brain health. These may include careful monitoring during surgery, good management of blood pressure and oxygen levels, and support during recovery. Staying mentally active and physically healthy after surgery may also help maintain brain function.
This research is important because it provides new insight into how the body and brain respond to repeated medical procedures. It also opens the door for future studies to find ways to reduce these risks and protect patients.
The study was published in the journal The Lancet Healthy Longevity. It adds to growing evidence that long-term brain health should be considered as part of overall medical care, especially for older adults.
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