The Impact of Rural Residence on Depression in the Ginkgo Evaluation of Memory Study

Abstract

Introduction: Residence in rural environments has been linked to substantial health disparities including elevated incidence of depression. Risks caused by the rural environment may be due to differences in environmental exposures and their demonstrated impacts on the brain, disparities in access to mental health care, and increased poverty. Geocoding challenges, difficulties in environmental exposure assessment, and small, widely dispersed populations are barriers to doing research in rural areas. Nevertheless, it is critical to include these populations, which have been underrepresented in environmental public health research.Methods: More than 3,000 participants 75 years of age and older residing in four communities in the US were followed between 2000-2008 in the Ginkgo Evaluation of Memory Study (GEMS). Rurality was defined by zip code-level Rural-Urban Commuting Area (RUCA) Version 2 codes. The Centers for Epidemiologic Studies – Depression scale was used to assess depression at baseline and twice a year during follow-up. We evaluated the relationship between RUCA code and depression at baseline using linear regression adjusted for sociodemographic factors and study community. Potential modification of the effect of rurality by study community was also examined.Results: Most GEMS participants resided in “metropolitan” areas. Preliminary analyses indicate no overall impact of RUCA code on depression score but that the impact of a one-unit increase in RUCA code was associated with a small but significantly greater increase (0.56; 95% CI: 0.17, 0.96) in depression score in Washington County, Maryland, relative to Pittsburgh, Pennsylvania.Conclusions: Findings suggest that the effect of rurality on prevalent depression varies by community. Future analyses will examine potential interactions of rural residence and environmental exposures and their impact on change in depression score over time.