Both studies were presented at the annual meeting of the American Society for Metabolic & Bariatric Surgery in Orlando.
''In the morbidly obese patient, there is a very good chance their migraine headache can improve or totally go away if you do a gastric bypass for their morbid obesity," says researcher Isaac Samuel, MD, associate professor of surgery at the University of Iowa Carver College of Medicine, Iowa City.
''Bariatric surgery has been shown to reduce the risk of heart attack, stroke or death by 25% to 50% compared to other surgical patients,'' says researcher John David Scott, MD, assistant professor of surgery at Greenville Hospital System University Medical Center in Greenville, S.C.
More than 15 million Americans are classified as morbidly obese. Either they have a body mass index (BMI) of 40 or above or a BMI of 35 or higher with an obesity-related disease such as type 2 diabetes.
About 220,000 bariatric surgeries are performed each year in the U.S., according to Society estimates. The cost is $11,500 to $26,000.
The link between obesity and migraines is debated, says Samuel.
Experts agree that obesity increases the severity and incidence of migraine, he says. "What they do not agree on is whether there is an increased risk of migraine in the obese population."
In his study, he looked at 81 patients, mostly women, with an average BMI of 48. Their average age was 40.
"All were on medications [for migraine]," he tells WebMD.
He separated the 81 people into two groups, according to when their migraines started. After excluding six due to unknown status, he evaluated 51 whose migraines developed after their obesity and 24 whose migraines occurred before their obesity. He followed the people for up to 8.5 years.
Of the 51 who developed migraines after obesity, 48 showed improvement after the surgery. Forty-one of these no longer had migraines.
Of the 24 who developed migraines before their obesity, 18 had improvement, including 11 who got rid of the migraines.
''If your migraine onset was after your obesity, the chances of total resolution are much higher," he tells WebMD.
Why the surgery reduces or wipes out the migraines is not known, he says.
He speculates that hormonal changes from the surgery could explain it.