Racial differences in the incidence of gliomas: a retrospective study from Memphis, Tennessee

This study records the incidence of glioblastoma multiforme, astrocytoma and oligodendroglioma in the white and Black patients in the Memphis Statistical Metropolitan Area (MSMA) during a 10.5-year period from 1 January 1984 through 30 June 1994. During this time, only six hospitals performed craniotomy and computer tomography (CT) scanning was routine in each of the hospitals. A total of 824 histologically confirmed first diagnoses were made at these six area hospitals. Based on the zip code listed as the home address, we determined patient's locale and identified 373 patients (232 glioblastoma multiforme, 106 astrocytomas and 35 oligodendroglioma) who resided in the area during the study interval. There were 50 black and 323 white patients. The background population for the area was obtained from the US Census Bureau's statistics for the year 1990. These statistics indicated that 40.5% of the population identified themselves as black and 57.9% as white. Age adjusted incidence rates were 1.550 (p < 0.001) for other astrocytomas, and 0.106 and 0.461 (p = 0.003) in the black and white populations, respectively. There was no significant difference in survival between the two populations. This study confirms a significant disparity in incidence rates for the three most common gliomas between the black and white populations and this disparity is higher than predicted by previous reports.