ODENSE, Denmark, March 1 (UPI) -- While there are risks for older people who have surgery, researchers in Denmark found in a large study of twins the risk for cognitive impairment does not increase because of anesthesia.
The finding is significant because some people over age 65 opt against surgeries that may improve their quality of life because of other health risks.
Postoperative cognitive dysfunction is normal for a few weeks after surgery, but researchers were unsure whether it turns into long-term memory loss as a result of surgery and anesthesia interacting with other health conditions.
"It is important to know whether surgery and anesthesia have any negative effects, especially with regard to preoperative counseling of the patient," Unni Dokkedal, a researcher at the University of Southern Denmark, said in a press release. "This research has the potential to become a key piece of this very complex research puzzle."
For the study, published in the journal Anesthesiology, researchers reviewed medical records for 4,299 middle-aged twins younger than 70 and 4,204 elderly twins over age 70. All the participants were residents of Denmark.
The researchers compared cognitive tests of twins who had not had surgery with those who had been exposed to anesthesia during surgery for major, minor, hip, or knee surgery at some point between 18 and 24 years before the study.
While twins who underwent major surgery had slightly lower scores, the researchers reported no statistically significant differences between the groups. This held true for participants with surgeries anywhere from three months to two years before the study, showing little effect from anesthesia beyond the weeks immediately following a procedure.
Researchers said other health conditions should be considered when calculating cognitive risk after a surgery, as the impact of genetic and other environmental factors.
"Our use of twins in the study provides a powerful approach to detect subtle effects of surgery and anesthesia on cognitive functioning by minimizing the risk that the true effects of surgery and anesthesia are mixed up with other environmental and genetic factors," Dokkedal said. "We found no significant cognitive effects related to surgery and anesthesia in these patients, suggesting that other factors, such as preoperative cognitive levels and underlying diseases, are more important to cognitive functioning in aging patients following surgery."