The present study was designed to examine if the relationship between lifetime history of TBI with LOC and disability differs by location of living (Appalachian vs. non-Appalachian and/or rural vs. urban). The main finding showed that living in an Appalachian or rural area and/or having lifetime history of TBI with LOC is associated with increased risk for reporting at least one type of impairment leading to disability compared to those living in a non-Appalachian or urban area and having no lifetime history of TBI with LOC, respectively. However, the interaction of these two factors did not further increase the risk for any of the disability outcomes as indicated by overlapping confidence intervals. Both living in an Appalachian area and having lifetime history of TBI with LOC were associated with increased risk for all six sources of disability, while living in a rural area was only associated with an increased risk for visual, mobility, and independent living impairments. Taken together, our findings suggest that living in Appalachian and/or rural areas and having a lifetime history of TBI with LOC are two important risk factors for disability. Our findings suggest that future interventions targeting reducing and/or managing disabilities due to TBI need to consider location of living and be designed to address the specific needs of Appalachian and/or rural residents.
This is the first study to address the possible influence of living in an Appalachian and/or rural area on the relationship between lifetime history of TBI with LOC and disability. While living in an Appalachian and/or rural area and lifetime history of TBI with LOC both contributed to increased risk of disabilities, lifetime history of TBI with LOC had a greater contribution to the majority of the disability outcomes. This was demonstrated by the greater RRs among the Appalachian and rural groups with a lifetime history of TBI with LOC and non-overlapping confidence intervals between these groups, compared to the Appalachian and rural groups without a lifetime history of TBI with LOC, respectively. These findings are consistent with previous evidence that lifetime history of TBI with LOC is associated with greater risk of all six sources of disability (Sarmiento et al. 2022; Yi et al. 2018). It is possible that factors outside the scope of this study, such as migration and health care utilization, may impact this relationship. Future research addressing TBI and health disparities, including disability, in Appalachian populations should address both migration and health care utilization.
Living in an Appalachian area, regardless of lifetime history of TBI with LOC, was associated with increased risk for any disability as well as all six sources of disability. This finding is consistent with previous research demonstrating health disparities in the Appalachian population. For example, a population-based study using the 2013–2016 North Carolina BRFSS data found that prevalence of all six sources of disability was higher among Appalachian vs non-Appalachian residents (Bouldin et al. 2020). Additionally, the current study found living in an Appalachian area was associated with reporting multiple disabilities. These relationships were maintained after adjusting for gender, race, and age group, suggesting that some aspect(s) of the Appalachian environment, culture, or lifestyle (e.g., greater rates of poverty and decreased access to healthcare) may contribute to these disparities (Wewers et al. 2006; Bouldin et al. 2020; Pollard et al. 2021). Indeed, the World Health Organization suggests that personal and environmental factors, including health conditions, social structure, and available support systems, interact to impact disability (World Health Organization 2002). Given that Appalachian regions, including those in Ohio, are typically associated with lower socioeconomic status (ARC 2021; Pollard et al. 2021), it is likely that income significantly contributes to this disparity (Bouldin et al. 2020). However, further research is needed to determine the direct causes of increased risk of disability among those with a lifetime history of TBI.
Living in a rural area, regardless of lifetime history of TBI with LOC, was associated with increased risk for having any disability and a visual, mobility, or independent living-related issue leading to disability. Consistent with our findings, a recent study using the 2016 National BRFSS data found that those living in rural areas reported higher rates of disability than those in urban areas, including visual, mobility, and independent living-related disabilities (Zhao et al. 2019). While the study also found this difference among cognitive, auditory, and self-care, our study did not. The inconsistent findings may be due to the operationalization of rurality, as our study used a dichotomous definition (rural vs. urban) while the previous study used a more complex definition with 6 different categories (Zhao et al. 2019). Future research addressing the impact of rurality on relationships between lifetime history of TBI and disability may consider using different definitions of rurality to address this and other similar research questions, as evidence has shown that the definition of rurality can impact observed relationships (Hawley et al. 2016; Isserman 2016; Owen et al. 2007).
The findings from the present study suggest that living in an Appalachian area may have further health disadvantages than living in a rural area. Those living in Appalachian areas of Ohio have lower income and are less likely to have health insurance coverage than those living in non-Appalachian areas of Ohio (Pollard et al. 2021). Given that the largest differences in disability are observed between large metropolitan and the most remote rural areas (Zhao et al. 2019), it is possible that greater lack of access to resources may contribute to the additional disparity among Appalachian populations.
Limitations
The use of a cross-sectional, retrospective design and lack of knowledge regarding disability status prior to TBI prevents the study from addressing the causal relationships between location of living, lifetime history of TBI with LOC, and disability. Longitudinal, prospective study designs should be used in future research to address these limitations. A second limitation was the use of self-report data. Though measures used for lifetime history of TBI and disability have been well validated, as with any self-report, it is possible that recall bias or social desirability may have impacted our findings. Finally, our study did not measure availability of, access to, or utilization of health care services, which are likely impacted by location of living and may be relevant to the study findings. Future studies should consider the availability, accessibility, and utilization of health care among those with lifetime history of TBI and how these factors may influence the relationships discussed in this study.