Risk Factors

A risk factor is anything that increases a person’s chance of developing a brain tumor. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of a brain tumor, most do not directly cause cancer a brain tumor. Some people with several risk factors never develop a brain tumor, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health care choices.

In most cases, the cause of a brain tumor is unknown. The following factors may raise a person’s risk of developing a brain tumor:

Age. Children and older adults are the two groups most likely to be diagnosed with brain tumors, although a brain tumor can occur at any age.

Gender. Men are generally more likely than women to develop gliomas, while women are more likely to have meningiomas.

Home/occupational exposures. Occupational exposures to solvents, pesticides, oil products, rubber, or vinyl chloride may increase the risk of developing a brain tumor, although there is no scientific evidence to date.

Family history. About 5% of brain tumor cases may be linked to hereditary (genetic) factors or conditions, including Li-Fraumeni syndrome, neurofibromatosis, nevoid basal cell carcinoma syndrome, tuberous sclerosis, Turcot syndrome, and von Hippel-Lindau disease. Scientists are also aware of sporadic “clusters” of brain tumors within some families without a link to these known hereditary conditions, and studies are underway to try to find a cause.

Exposure to infections, viruses, and allergens. Infection with the Epstein-Barr virus (EBV) increases the risk of CNS lymphoma; EBV is more commonly known as the virus that causes mononucleosis. In other research, high levels of a common virus called cytomegalovirus (CMV) have been found in brain tumor tissue; the meaning of this finding is under investigation. Several types of other viruses have been shown to cause brain tumors in experimental animal studies; however, more data are needed to determine if exposure to infections, other viruses, or allergens affect the risk of a brain tumor in people.

Electromagnetic fields. Electromagnetic fields, such as energy from power lines or from cell phone use, may or may not increase the risk of developing a brain tumor, as current research has shown conflicting results. The World Health Organization (WHO) recommends limiting cell phone use and promotes the use of a headset for both adults and children.

Race and ethnicity. In the United States, white people have higher rates of gliomas but lower rates of meningiomas than black people. Also, the rate of malignant brain tumors in Japan is less than half the rate found in northern Europe.

Ionizing radiation. Previous treatment to the brain or head with ionizing radiation (including x-rays) has shown, in some cases, to be a risk factor for a brain tumor.

Head injury and seizures. Serious head trauma has long been studied for its relationship to brain tumors. Some studies have shown a link between head trauma and meningioma, but not one between head trauma and glioma. A history of seizures has long been associated with brain tumors, but because a brain tumor can cause seizures, it is not known if seizures increase the risk of brain tumors, if seizures occur as a consequence of the tumor, or if anti-seizure medication increases the risk.

N-nitroso compounds. Some studies of diet and vitamin supplementation seem to indicate that dietary N-nitroso compounds may raise the risk of both childhood and adult brain tumors. Dietary N-nitroso compounds are found in some cured meats, cigarette smoke, and cosmetics. However, additional research is necessary before a definitive link can be established.

Exposure to nerve agents. One study has shown that some Gulf War veterans are at increased risk of a brain tumor due to exposure to nerve agents; however, additional research is necessary before a definitive link can be established.

At this time, there are no known means of preventing a brain tumor.