Brain Tumors: Primary - Risk Factors

Studies on the effects of lower-energy radiation, such as microwaves and electromagnetic fields, have been uncertain. One study reported that men whose jobs exposed them to electromagnetic fields had higher rates for brain cancer, although a more recent study found a higher risk only in men who were also exposed to chemicals (petroleum, solvents, lead, pesticides and herbicides).

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A 2002 study on Korean War veterans highly exposed to microwaves from radar equipment reported no excess risk for brain cancer--or any other malignancy--over a 40-year period. Studies in both 2000 and 2001 found no evidence to suggest a higher risk with cellular phones and other wireless devices that use radiofrequency.

Chemical and Metals in Brain Tumors. High exposure to a number of metals and chemicals have been associated with brain tumors, such as the following:

High exposure to certain chemicals, including vinyl chloride and petroleum products, has been associated with brain tumors.
High levels of lead, arsenic, or mercury exposure have been linked to a higher risk. One study suggested that lead exposure was particularly associated with meningiomas. It is unknown whether these associations are real, and confirmatory studies are needed.
There has been some suggestion of a higher risk with exposure to pesticides.A major study of pesticides is underway, but results are not in yet. A 2003 study indicated that parental exposure to pesticides or herbicides did not appear to be important in increasing risk for brain cancer in their children.

Brain cancer is uncommon, and, over the course of their lifetime, many people are exposed to these chemicals, many of which are very common. To date, there has been no clear evidence that implicates any specific industrial chemical or metal.

Inherited Disorders

About 5% of primary brain tumors are associated with hereditary disorders. They include the following:

Li-Fraumeni cancer family syndrome
Tuberous sclerosis
Von Recklinghausen disease (neurofibromatosis)
Von Hippel Lindau disease
Familial polyposis (Turcot's syndrome)
Osler-Weber-Rendu syndrome

Organ Transplantation

A 2002 study reported a higher risk for brain cancers in patients who had undergone organ transplantations. Researchers believed that the drugs used to suppress the immune response after the procedures may increase the risk.

Medical Conditions Associated with a Lower Risk for Brain Tumors

A 2002 study reported lower risks for brain cancers in individuals with allergies and autoimmune diseases (such as type 1 diabetes). Autoimmune diseases were also associated with a lower risk for meningiomas. The cause of this possible association remains unknown.

Studies have also found an association between lower risk for gliomas and a history of infection with varicella zoster, the virus that causes chicken pox and shingles.