The Association of Neighborhood Socioeconomic Status with Access to Chiropractic Providers: A Geospatial Analysis of Two U.S. Geographic Regions

BACKGROUND: Chiropractic care for common musculoskeletal conditions such as low back pain typically includes guideline-concordant first-line nonpharmacologic treatments. However, geographic variability in access to chiropractic care and whether variability relates to neighborhood socioeconomic status (SES) is understudied. METHODS: In this geospatial analysis, we evaluated the association between neighborhood SES and the number of chiropractic providers in two U.S. geographic regions. Neighborhood SES was defined using the area deprivation index (ADI) for each neighborhood (defined as a census block group) in Suffolk County, MA, and Cuyahoga County, OH. Higher ADI scores (range 1-10) indicate worse neighborhood SES. Chiropractic providers were identified through triangulation of publicly available sources and geocoded to map provider locations. From each neighborhood centroid, we identified providers within nine catchment areas based on distance or travel times. Associations between ADI rank and the number of providers were evaluated using Poisson regression to estimate incident rate ratios (IRRs), adjusting for neighborhood population size. RESULTS: We identified 92 providers across 628 neighborhoods in Suffolk County and 214 providers across 1135 neighborhoods in Cuyahoga County. In Suffolk County, using the smallest distance-based catchment area (0.5 miles), compared to the low ADI tertile (mean = 3.9 providers), access was lower in the middle (mean = 1.3 providers; IRR = 0.31, 95% confidence intervals [CI] = 0.27-0.35) and high (mean = 0.9 providers; IRR = 0.21, 95% CI = 0.18-0.25) tertiles. We observed a similar graded association when considering broader catchment areas and those defined by walking and driving times. Results were similar in Cuyahoga County, although there was no difference in the middle tertile, and the association was attenuated in the high ADI tertile for individuals in the 15-min drive catchment area. CONCLUSIONS: Geographic areas with worse neighborhood SES had fewer chiropractic providers after controlling for population size. Further work is needed to evaluate and encourage equitable geographic distributions of chiropractic providers.