(RxWiki News) In the hunt for potential risk factors for two types of brain tumors, obesity may be a suspect.
A new study from Germany found that patients who were overweight or obese were at an increased risk of developing brain tumors called meningiomas.
"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," said lead study author Gundula Behrens, PhD, a statistician at the University of Regensburg in Germany, in a press release. "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."
A meningioma is a tumor that occurs in the meninges (the membranes that surround the brain and spinal cord). Most meningiomas are noncancerous or benign, but, rarely, these tumors can be malignant.
Meningiomas are one of the two most common types of brain tumors. The other type is a called a glioma. Past research has suggested that there may be a link between obesity and these tumors.
Carmen T. Ramirez, MD, a neurologist at Baylor Scott & White Medical Center - Irving, TX, offered some potential reasons behind the link this study found.
"There have been studies that are suggestive of the fact that increased insulin is related to higher ... insulin-like growth factors, which may act on tumors like meningiomas and other entities," Dr. Ramirez told dailyRx News. "Estrogen has increased production in adipose [fat] tissues, and the balance between estrogen and testosterone may lead to more circulating testosterone in obese females, which has had some association with tumor growth."
For this study, Dr. Behrens and team looked at 18 studies on obesity and these two types of brain tumors. These studies included data on 2,982 meningioma and 3,057 glioma cases.
Overweight patients were 21 percent more likely to develop meningiomas than normal-weight patients. Obese patients were 54 percent more likely.
No such link was found between either weight problem and gliomas.
Physical activity was found to decrease the risk of meningiomas but not the risk of gliomas — patients who reported the highest levels of physical activity were 27 percent less likely to develop meningiomas than those who reported lower levels.
According to Dr. Behrens and team, high levels of insulin and estrogen may also be linked to meningioma risk.
Excess weight increases estrogen production. Insulin (the hormone that regulates blood sugar) is commonly raised in obese patients.
This study was published Sept. 16 in the journal Neurology.
The Department of Epidemiology and Preventive Medicine at the University of Regensburg funded this research. No conflicts of interest were disclosed.