Geospatially illustrating regional-based oral health disparities in Kentucky

Oral Health Service Access in Racial/Ethnic Minority Neighborhoods: A Geospatial Analysis in Washington, DC, USA

Previous studies on individual-level variables have improved our knowledge base of oral health service use. However, environmental or contextual variables are also important in understanding oral health disparities in racial and ethnic neighborhoods. Based on Bronfenbrenner’s ecological framework, this study examines the geographic availability of oral health providers in Washing-ton DC, U.S.A. Census tract-level data were drawn from the American Community Survey, joined with tract-level shapefiles, and overlaid with the geographic location of dental services throughout the city. Visual maps, descriptive statistics, and spatial lag regression models showed that census tracts with higher concentrations of African Americans were significantly farther from their nearest oral health providers (r = 0.19, p < 0.001), after controlling for neighborhood poverty rate, median age, and gender. Such findings confirm that in urban areas with highly di-verse populations such as Washington DC, racial disparities in oral health care access are signifi-cant. The study highlights that identifying neighborhoods with limited oral health care providers should be a priority in diminishing racial disparities in oral health service access. Improving access to racial/ethnic minority communities, especially African American neighborhoods, will require changes in health policies and programs, workforce development, resource allocation, community outreach, and educational programs.

Visualizing the Geography of HIV Observational Cohorts With Density-Adjusted Cartograms

BACKGROUND

Maps are potent tools for describing the spatial distribution of population and disease characteristics and, thereby, for appropriately targeting public health interventions. People with HIV (PWH) tend to live in densely populated and spatially compact areas that may be difficult to visualize on maps using unadjusted geographic or political borders.

SETTING

To illustrate these challenges, we used geographic data from adult PWH at the Vanderbilt Comprehensive Care Clinic (VCCC) in Nashville, Tennessee, and aggregated data from the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) from 1998 to 2015.

METHODS

We compared choropleth maps that use differential shading of political/geographic boundaries with density-adjusted cartograms that allow for shading and deformed boundaries according to a variable of interest, such as PWH.

RESULTS

Cartograms enlarged high-burden areas and shrank low-burden areas of PWH, improving visual interpretation of where to focus HIV prevention and mitigation efforts, when compared with choropleth maps. Cartograms may also demonstrate cohort representativeness of underlying populations (eg, Tennessee for VCCC or the United States for NA-ACCORD), which can guide efforts to assess external validity and improve generalizability.

CONCLUSION

Choropleth maps and cartograms offer powerful visual evidence of the geographic distribution of HIV disease and cohort representation and should be used to guide targeted public health interventions.

Emulation of Community Water Fluoridation Coverage Across US Counties

INTRODUCTION

Expansion of community water fluoridation has stalled in the United States, leaving 115 million Americans without fluoridated drinking water.

OBJECTIVE

This study used spatial regression methods to assess contributions of supply-side factors (neighboring counties' fluoridation coverage) and demand-side factors (health literacy, education, and population density of the local county) in predicting the extent of fluoridation in US counties.

METHODS

For this cross-sectional ecological analysis, data from the 2014 Water Fluoridation Reporting System for all 3,135 US counties were merged with sociodemographic data from the 2014 American Community Survey and county-level estimates of health literacy based on the National Association of Adult Literacy Survey. We employed multilevel geographically weighted autoregressive models to predict fluoridation coverage of each county as a function of fluoridation coverage of neighboring counties and local-county covariates: either health literacy or sociodemographic characteristics. Akaike's Information Criterion was used to distinguish the better model in terms of explanatory power and parsimony.

RESULTS

In the best-fit model, an increase from the first to third quartile of neighboring counties' fluoridation coverage was associated with an increase of 27.76 percentage points (95% confidence limits [CI] = 27.71, 27.81) in a local county's fluoridation coverage, while an increase from the first to third quartile of local county's health literacy was associated with an increase of 2.8 percentage points (95% CL = 2.68, 2.89). The results are consistent with a process of emulation, in which counties implement fluoridation based upon their population's health literacy and the extent of fluoridation practiced in neighboring counties.

CONCLUSION

These results suggest that demand for community water fluoridation will increase as health literacy increases within a county. Furthermore, when considering expansion of fluoridation, non-fluoridated communities can benefit from precedents from nearby communities that are fluoridated.

KNOWLEDGE TRANSFER STATEMENT

Expanded coverage of community water fluoridation has stalled in the United States. The economic theory of diffusion describes how, over time and space, policy enacted in one community can influence public opinion in a neighboring community. This study applies geospatial analysis of county-level data and the theory of policy diffusion to demonstrate that fluoridated counties can promote the implementation of community water fluoridation in their neighboring, non-fluoridated communities.

Dental workforce availability and dental services utilization in Appalachia: a geospatial analysis

OBJECTIVES

There is considerable variation in dental services utilization across Appalachian counties, and a plausible explanation is that individuals in some geographical areas do not utilize dental care due to dental workforce shortage. We conducted an ecological study on dental workforce availability and dental services utilization in Appalachia.

METHODS

We derived county-level (n = 364) data on demographic and socioeconomic characteristics and dental services utilization in Appalachia from the 2010 Behavioral Risk Factor Surveillance System (BRFSS) using person-level data. We obtained county-level dental workforce availability and physician-to-population ratio estimates from Area Health Resources File and linked them to the county-level BRFSS data. The dependent variable was the proportion using dental services within the last year in each county (ranging from 16.6% to 91.0%). We described the association between dental workforce availability and dental services utilization using ordinary least squares regression and spatial regression techniques. Spatial analyses consisted of bivariate local indicators of spatial association (LISA) and geographically weighted regression (GWR).

RESULTS

Bivariate LISA showed that counties in the central and southern Appalachian regions had significant (P < 0.05) low-low spatial clusters (low dental workforce availability, low percent dental services utilization). GWR revealed considerable local variations in the association between dental utilization and dental workforce availability. In the multivariate GWR models, 8.5% (t-statistics > 1.96) and 13.45% (t-statistics > 1.96) of counties showed positive and statistically significant relationships between the dental services utilization and workforce availability of dentists and dental hygienists, respectively.

CONCLUSIONS

Dental workforce availability was associated with dental services utilization in the Appalachian region; however, this association was not statistically significant in all counties. The findings suggest that program and policy efforts to improve dental services utilization need to focus on factors other than increasing the dental workforce availability for many counties in Appalachia.

A cross-sectional study on health differences between rural and non-rural U.S. counties using the County Health Rankings

Background

By examining 2013 County Health Rankings and Roadmaps data from the University of Wisconsin and the Robert Wood Johnson Foundation, this paper seeks to add to the available literature on health variances between United States residents living in rural and non-rural areas. We believe this is the first study to use the Rankings data to measure rural and urban health differences across the United States and therefore highlights the national need to address shortfalls in rural healthcare and overall health. The data indicates that U.S. residents living in rural counties are generally in poorer health than their urban counterparts.

Methods

We used 2013 County Health Rankings data to evaluate differences across the six domains of interest (mortality, morbidity, health behaviors, clinical care, social and economic factors, and physical environment) for rural and non-rural U.S. counties. This is a cross-sectional study employing chi-square analysis and logit regression.

Results

We found that residents living in rural U.S. counties are more likely to have poorer health outcomes along a variety of measurements that comprise the County Health Rankings’ indexed domains of health quality. These populations have statistically significantly (p ≤ 0.05) lower scores in such areas as health behavior, morbidity factors, clinical care, and the physical environment. We attribute the differences to a variety of factors including limitations in infrastructure, socioeconomic differences, insurance coverage deficiencies, and higher rates of traffic fatalities and accidents.

Discussions

The largest differences between rural and non-rural counties were in the indexed domains of mortality and clinical care.

Conclusions

Our analysis revealed differences in health outcomes in the County Health Rankings’ indexed domains between rural and non-rural U.S. counties. We also describe limitations and offer commentary on the need for more uniform measurements in the classification of the terms rural and non-rural. These results can influence practitioners and policy makers in guiding future research and when deciding on funding allocation.

The ethical imperative of addressing oral health disparities: a unifying framework

Health disparities are preventable differences in the burden of disease or opportunities to achieve optimal health that are experienced by socially disadvantaged population groups. Reducing health disparities has been identified as an ethical imperative by the World Health Organization's Commission on Social Determinants of Health and numerous other national and international bodies. Significant progress has been made over the past years in identifying vulnerable groups, and 'distal' factors including political, economic, social, and community characteristics are now considered pivotal. It is thus unsurprising that the remarkable advances in the science and practice of dentistry have not led to notable reductions in oral health disparities. In this review, we summarize recent work and emphasize the need for a solid theoretical framing to guide oral health disparities research. We provide a theoretical framework outlining pathways that operate across the continuum of oral health determinants during the lifecourse and highlight potential areas for intervention. Because oral health disparities emanate from the unequal distribution of social, political, economic, and environmental resources, tangible progress is likely to be realized only by a global movement and concerted efforts by all stakeholders, including policymakers, the civil society, and academic, professional, and scientific bodies.