Regional variations in the incidence of brain glioma in adults in alabama

Abstract BACKGROUND Gliomas are the most common primary brain tumor in adults in the US with an annual age-adjusted incidence rate (AAA-IR) of 4.67 to 5.73 per 100,000 persons. There are several sources of carcinogenic contaminants in northeast Alabama and western Georgia with the Coosa River serving as the region’s primary water source. We aimed to examine the incidence rate of glioma, as well as tumor characteristics and overall survival, in northeast Alabama compared to the rest of the state. METHODS This is a retrospective cohort study using the UAB Neuro-Oncology clinic database including adult patients ( ≥ 20 years at diagnosis) with histologically confirmed diagnosis of glioma (ICD10: 71.9) residing in the state of Alabama at the time of diagnosis between January 2015 and December 2019. We calculated AAA-IR among residents in counties intersected by the Coosa River in northeast Alabama (exposed group) compared to the rest of the state (non-exposed group). The electronic medical records of the participants were reviewed for patient demographics, insurance status, tumor grade and molecular markers, as well as the vital status. The overall survival was graphically examined using Kaplan-Meier. RESULTS A total of 660 patients were included in this study (528 non-exposed, and 132 exposed). The AAA-IR of glioma in the exposed group was 4.76 per 100,000 persons vs 3.14 per 100,000 persons in the non-exposed group with a 50 % higher incidence rate of glioma in the exposed group (RR = 1.50; 95% CI, 1.22-1.89). There was no statistically significant difference between the two groups with respect to age at diagnosis, sex, race, surgery type, tumor grade, IDH status, or overall survival. CONCLUSIONS Our findings indicate a higher incidence of glioma in northeast Alabama. Future geospatial and population-based epidemiological investigations are needed to identify possible regional environmental risk factors and examine temporal sequence.