Being Overweight May Increase Risk of Type of Brain Tumor Being overweight or obese may be tied to an increased risk of a type of brain tumor called meningioma, according to a research in the online issue of Neurologyå¨, the medical journal of the American Academy of Neurology. A meningioma is a tumor that arises from the meninges ÛÓ the membranes that surround your brain and spinal cord. Most meningiomas are noncancerous (benign), though rarely a meningioma may be cancerous (malignant). Meningiomas occur at a rate of about five to eight cases per 100,000 people per year. The five-year survival rate for meningioma is 63 percent. ÛÏThis 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,Û said meta-analysis author Gundula Behrens, PhD, of the University of Regensburg in Regensburg, Germany. ÛÏGiven 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.Û A total of 12 studies on body mass index and six on physical activity were analyzed, involving nearly 6.000 cases. The analysis found that compared to people with a normal weight, overweight people were 21 percent more likely to develop a meningioma and obese people were 54 percent more likely to develop one. Overweight was defined as having a BMI of 25 to 29.9; obese was considered a BMI of 30 or higher. Having a high level of physical activity was modestly associated with a decreased risk of meningioma. Those with the highest amount of physical activity were 27 percent less likely to have a meningioma than those with the lowest amount of activity. Behrens said several biological processes could potentially link excess weight and increased risk of meningioma. For example, excess weight is associated with excess production of estrogen, and estrogens promote the development of meningioma. Also, excess weight is linked to high levels of insulin, which could promote meningioma growth. Another good argument for diet and exercise.