The study compared the rate of brain cancer among people with low income (those enrolled in Medicaid) to all other people who developed brain cancer in the state of Michigan. Medicaid is a government program providing medical assistance for people with very low incomes. The study was conducted by identifying all of the new cases of brain cancer that occurred during a two-year period in the state of Michigan, and classifying those with low income as those who were eligible for Medicaid. Brain cancer cases occurring in people under age 25 or over age 84 were not included. A total of 1,006 cases were studied.
The overall rate of brain cancer was 8.1 cases per 100,000 people. Of those with low incomes, there were 14.2 cases per 100,000 people, compared to 7.5 cases per 100,000 for all other persons.
The difference was greatest among younger people. Men under age 44 with low incomes were at least four times more likely to develop brain cancer than those not classified as having low income. Women with low incomes under age 44 were at least 2.6 times more likely to develop brain cancer than those who were not classified as having low income.
The difference grew smaller with age. For people over age 67, there was no significant difference in the likelihood of developing brain cancer between persons with a low income and all other persons.
Although it's possible that the results are because people with brain tumors become eligible for Medicaid due to disability from the tumor, the researchers feel there are other reasons for the results.
"The short survival time for this type of cancer combined with the Medicaid requirement that you spend your assets and be disabled for at least 12 months may make it difficult for a middle-class person to become eligible for Medicaid during the two-year period of the study," said study author Paula Sherwood, RN, PhD, CNRN, of Michigan State University. In addition, further analysis of only those who were eligible for Medicaid before their diagnosis supported the study findings.
The researchers don't know why low income is associated with higher rates of brain cancer. "Poverty may accelerate the onset of cancer in people who are biologically predisposed to develop it," Sherwood said. "Low-income status is also associated with environmental factors such as exposure to toxins, quality of nutrition and shelter, and education and health factors. Additional, larger studies may help shed some light. Also, these results can help us target treatments and educational programs to groups that are more at risk."
Some previous studies have shown that people with high incomes may be more likely to develop brain cancer. Sherwood said that this study does not shed light on the risk for people with high incomes, because information was not collected on the income of those not on Medicaid.
The study was supported by the Michigan State University Institute for Health Care Studies, Department of Human Medicine, Department of Family Practice, the Michigan Department of Community Health, National Institute of Nursing Research (F31 NR08069), National Institutes of Health, American Cancer Society, Walther Cancer Institute, and the Michigan State University College of Nursing.
The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as stroke, Alzheimer's disease, epilepsy, Parkinson's disease, autism and multiple
sclerosis. For more information about the American Academy of Neurology, visit its website at www.aan.com/press.