The researchers -- led by Gundula Behrens, Ph.D., University of Regensburg in Germany – discovered that obese people were 54 percent more likely to develop a meningioma, while overweight people were 21 percent more likely to develop one, as compared with people of a normal body weight. The analysis analyzed 12 studies on body mass index (BMI), and six on physical activity, involving 3,057 glioma cases and 2,982 meningioma cases. The two are the most prevalent primary brain tumors in adults, each occurring at a rate of about five to eight cases per 100,000 people per year. Meningioma offers a better prognosis than glioma, with a five-year survival rate of 63 percent. The study did not find any relationship between weight and glioma.
Researchers defined individuals to be obese if they had a BMI of 30 or higher. They defined overweight as having a BMI of 25 to 29.9.
According to Behrens, “This is an important finding since there are few known risk factors for meningioma and the ones we do know about are not things a person can change. Given the high prevalence of obesity and the unfavorable prognosis for this type of tumor, these findings may be relevant for strategies aimed at reducing the risk of meningioma.”
People with the highest level of physical activity were 27 percent less likely to have a meningioma than those with the lowest amount of activity. Behrens explained that multiple biological processes could be at play, linking excess weight and increased risk of meningioma. For instance, excess production of estrogen promotes the development of these tumors. Additionally, being overweight is linked to higher levels of insulin, which could promote meningioma growth.
“With physical activity, it’s possible that meningiomas that had not been diagnosed yet caused people to reduce their physical activity at the time it was measured,” Behrens said, noting that although the study shows an association between weight and this type of tumor, tumors are rare. The meta-analysis was supported by the Department of Epidemiology and Preventive Medicine, University of Regensburg, Germany.