Weight-loss surgery can change a person's life and health for the better, but new research warns it might also come with a slight risk of developing epilepsy.
People who had the surgery had a 45% relative increased risk of developing epilepsy, compared with people who did not have the surgery. Moreover, those who suffered a stroke after weight-loss surgery were 14 times more likely to develop epilepsy than those who did not have a stroke, Canadian researchers reported.
"Patients who are considering weight-loss surgery should discuss the benefits and risks of bariatric surgery with their doctor," said lead researcher Dr. Jorge Burneo, a professor of neurology at Western University in London, Ontario. "It's important to note that, though elevated, the risk of epilepsy following bariatric surgery is still quite low.
"The absolute risk is low," Burneo said. "We estimated it to be 16 per 100,000 patients during three years of the study."
It's not clear why bariatric surgery is associated with an increased risk for epilepsy, Burneo said.
"The mechanism is unknown, but possible mechanisms may include nutritional deficiencies and exposure to general anesthesia," he said.
For the study, Burneo's team collected data on nearly 17,000 people who had bariatric surgery over six years. They compared these patients with more than 622,000 obese patients who didn't have the procedure. The participants were followed for at least three years.
Over that time, 73 of those who had bariatric surgery developed epilepsy (0.4%), compared with 1,260 people who didn't have the procedure (0.2%), the researchers found.
The risk for epilepsy remained the same regardless of the type of weight-loss surgery a patient had, the researchers found. These included gastric bypass and sleeve gastrectomy. Both procedures reduce the size of the stomach, thus restricting the number of calories a patient can consume.
"The findings of this study are intriguing and future studies are needed to validate the results and explore possible mechanisms behind this," said Dr. Jessica Folek, director of bariatric surgery at Long Island Jewish Forest Hills in New York City.
"There are conditions which post-bariatric surgery can manifest similar to certain types of seizures, such as hypoglycemic episodes [episodes of low blood sugar]," she said. "Bariatric [weight-loss] surgery can lead to electrolyte abnormalities, mineral deficiencies, which might be a contributing factor."
Deficiency in B vitamins such as vitamin B12, B1 (thiamine) and B6 can cause nerve abnormalities and may be one of several possible mechanisms behind this association, Folek said.
"I would caution patients who might see these findings and say, 'I won't have bariatric surgery because it will increase my risk of developing seizure disorder,'" she said. "I would not let the results of this study dissuade patients from having surgery."
Bariatric surgery is lifesaving and can result in significant improvement, if not complete remission of numerous health problems, including type 2 diabetes and high blood pressure. It can also result in significant improvement in quality of life and decreased risk of dying from these health problems, Folek said.
"It's important for patients to know about this potential association if they have a history of seizures or epilepsy in childhood, as they may be more prone to developing seizures after bariatric surgery," she said. "But in the meantime, until more studies are done to validate these findings and explore possible mechanisms behind this association, I would advise patients to still pursue bariatric surgery if they suffer from morbid obesity."
The report was published online Sept. 28 in the journal Neurology.