Aging with long-term physical disability: Cohort analysis of survey sample in the U.S.

Introduction

Aging with a disability is the phenomenon of living long-term with impairment and disability that begins in early and/or mid-life and continues over the lifecourse.^1,2 Although investigation of aging with long-term physical disability (AwD) dates back over 30 years, to date, most of the research has been small-scale and focused primarily on individuals with lifelong and early-onset disabilities.^3–5 In contrast, our research focuses on persons AwD between the ages of 45 and 65 living in the United States, with disability onset from birth to age 60, to understand participation patterns and changes in this mid-life phase. It is fairly well-established that these individuals often experience the aging process earlier, at a faster rate, and report greater difficulty with independent living than their peers without physical disabilities.^6,7 The growing body of research related to AwD links disability-related fatigue, pain, and depression to problems participating in general or to reduced social participation.^8–10 Existing studies have also shown that increased levels of functional impairment, secondary health conditions (e.g., depression, fatigue, and sleep disturbance), and reduced mood and energy related to secondary health conditions significantly decrease satisfaction with social roles among persons AwD.¹¹ Additionally, there is a substantial body of evidence showing differences in the severity of disability and disability symptoms and trajectories among individuals in mid-life based on race and ethnicity.^12,13 However, limited research has investigated participation among persons AwD as a population group.⁹ Only a few research studies have explored AwD longitudinally.^1,14,15 Of those, the Aging and Quality of Life Survey at the University of Washington was the longest running, collecting seven waves of data from 2009–2018.¹⁶ That study produced important findings regarding persons AwD and health and wellness but offers limited information about participation. We seek to build on these findings by expanding our understanding into the realm of participation in life activities.

Our three-year cohort survey of persons AwD considers how and why participation changes over time. We aim to inform evidence-based interventions implemented by community organizations and service providers designed to facilitate participation of people with disabilities. Here, we report cohort sociodemographic, health, and disability traits from our first wave of data (collected August 2018 - July 2019) by age group. We also explore sample integrity by considering how our population compares to those existing in the current literature, based on the presence of normative AwD symptoms reported in the literature. The population of persons AwD is not well-represented in national datasets, as very few general population–based surveys in the United States include age of onset of conditions, symptoms, or disability, nor do they typically contain measures of pain, fatigue, and depression, which are often-measured symptoms related to AwD.^1,2 We take this first step to help validate our sample given the paucity of research focused on AwD. We want to ensure that we indeed have recruited a sample of individuals that reflects the traits of AwD samples in published research. There is no standard set of parameters for what makes a sample an AwD sample, versus a more generic sample of persons with disabilities.^1,2 We believe that the presence of AwD symptoms—given the commonality of their existence in the small body of AwD research—and one’s age at disability onset are the best current markers for identifying this subset of the broader disability population.

After we assess demographic and disability characteristics, we then assess ability to participate in, and satisfaction with, participation in social roles and activities to further review our cohort. This will be compared with findings in existing literature, in order to gain a better understanding of baseline social participation prior to the COVID-19 pandemic. Specifically, we identify sociodemographic, health, and disability variables associated with one’s ability to participate in, and satisfaction with, their participation in social roles and activities, and we then quantify the independent effects of the variables on these two aspects of social participation. Our social activity measures are drawn from the PROMIS (Patient Reported Outcomes Measurement Information System) measurement bank and have been evaluated across multiple populations.^17–19

AwD research study samples are frequently composed of persons who identify their race as White and who have a specific diagnosis such as spinal cord injury, multiple sclerosis, or polio,²⁰ which represent some of the common conditions found among persons AwD, but often do not include other conditions that cause disability. Guidelines from the United States federal funding agencies including the National Institutes of Health and the National Institute on Disability, Independent Living, and Rehabilitation Research²¹ have required researchers to improve the racial and ethnic diversity of their study samples, given the substantial differences in health and wellness outcomes for non-White individuals in the United States.²²

In our study, we actively sought to create a broader sample base by increasing the proportion of non-White participants and by recruiting participants based on self-report of physical disability, regardless of diagnosis. We worked closely with our Community-Based Research Network (CBRN),²³ a network of aging and disability providers and advocacy groups located in the state of Missouri in the United States, that work together to close the gap in the availability of evidence-based practices for persons AwD. The CBRN supported this cohort by identifying areas of importance for data collection, assisting with recruitment, and strategizing about increasing recruitment of participants of specific groups, including men and non-White individuals. Because of this, our study sample is distinct from other study samples of persons AwD in the literature. This reinforced our interest in evaluating the traits of our sample against those of other samples, before we begin our longitudinal analysis.

Our cohort study is guided by disability models considering person–environment interactions^24,25 and the World Health Organization’s International Classification of Function, Disability, and Health²⁶; Active Ageing policy framework²⁷; and Conceptual Framework for Action on the Social Determinants of Health.²⁸ Fundamentally, our study process and choices for measures are anchored in building our understanding of how the knowledge gained from this study can be useful to CBRN members and other community-based organizations, to support the participation of persons AwD. Finally, our study is situated within the COVID-19 pandemic. The pandemic has exacerbated socioeconomic, health, and independent living disparities for persons with disabilities in the United States.^29,30 Although this cohort study was not intended to evaluate participation among persons AwD before and during a pandemic, it has. Therefore, we believe it is crucial to understand how findings for baseline sample and social participation measures fit within the extant literature, so that we may have a better ability to tease apart the effects of the pandemic from more expected changes over time.

The questions we ask of our sample in this initial analysis are as follows. How do the sociodemographic and disability characteristics of our sample compare with those of other samples in AwD research and with the general population? How do social participation and predictors of social participation in our sample compare with findings in related studies of persons AwD? These questions support our dual aim of understanding how our sample compares with AwD samples reported in the published literature and providing a context for our future longitudinal analysis.

Methods

Results

The sample was two-thirds female, one participant identified as transgender, and four participants preferred not to answer the question. Participants had a mean age of 56.8 years (SD = 5.6) and a mean of 19.0 years living with their disability (SD = 13.7, range = 5–65). Seventy percent of participants resided in the state of Missouri; the state with the second most participants was Illinois, with 6.5%. Twenty-eight additional states across the United States were represented, each with ≤2% of participants The most frequently self-reported primary causes of physical disability were neurological (37%; e.g., cerebral palsy, multiple sclerosis, spinal cord disorders, traumatic brain injury) and musculoskeletal (26%; e.g., degenerative and osteoarthritis, spinal stenosis, amputation). Conditions related to respiratory (e.g., asthma, COPD, lung disease), endocrine (e.g., diabetes and thyroiditis), and immunological (e.g., rheumatoid arthritis, connective tissue disorders) systems each ranged from 5%–6% representation. Categories ranging between 0.5%–3% representation included the cardiovascular system, special senses and speech, digestive system, and hematological disorders. Eighty percent of participants reported reasons for their primary disability that can be categorized as having one cause of primary disability, based on SSA listing.

Chi-square tests showed that older participants (aged 55–60 and 61–65) had significantly lower rates of employment and marriage, higher rates of living alone, and had lived with their disability for longer (Table 1). Rates of Medicare,⁴² Social Security Disability Insurance (SSDI),⁴³ and Social Security retirement⁴⁴ benefits receipt were also higher among older participants (aged 55–60 and 61–65).

Over half of participants had at least some difficulty with seeing (53%), self-care (52%), or remembering or concentrating (63%); about one-quarter reported difficulty with hearing (25%) or communicating (22%). Ninety-four percent of participants were unable to walk or climb steps or had difficulty doing so. In the past 12 months, approximately 46% of participants reported that their health status had declined, and 54% of participants reported that their ability to do what they wanted to do in their daily lives had decreased. Table 2 presents health and function information for the total sample and differences by age group. Participants’ mean scores of AwD-related symptoms were all above general population averages of 50, with a fatigue mean of 59.0 (SD = 9.3, range = 24.3–84.7), a pain interference mean of 60.4 (SD = 10.0, range = 38.7–83.8), and a depression mean of 54.9 (SD = 10.1, range = 34.2–84.4). We did not find significant differences by age group for health and function measures.

Participants reported lower average ability to participate in social roles (M = 44.1, SD = 9.0, range = 21.5–67.5) and satisfaction with their participation in social roles (M = 43.5, SD = 9.8, range = 22.0–68.7) than the general population (t-score = 50). Table 3 presents data on each social participation measure by sociodemographic characteristics. Both ability to participate in, and satisfaction with, participation in social roles and activities were higher among Black/African American participants in comparison to White participants and those of other races.

Discussion

Findings from our analyses show that our cohort is distinct yet similar to the other AwD cohort study samples we identified. Its racial representation of nearly 39% non-White participants is higher than the only other cohort study of persons AwD we are aware of, which was roughly 90% White participants.^36,45 This may be a factor of study location or recruitment strategies. Seventy percent of our participants live in the state of Missouri where our study is based, which has a Black and African American population of approximately 12% overall; this increases to 25%–50% in urban areas.⁴⁶ Although there are notable exceptions in which studies have actively focused on non-White participants—for example, work by Walker et al.⁴⁷ focuses on predominantly Latina participants—broader racial and ethnic diversity is a major limitation in existing AwD research. We believe that the diversity of our sample will help broaden the applicability of cohort findings.

Our cohort has similar percentages of college/advanced education (71%) to the US general population (68%). A higher percentage, 62%, are single, compared to roughly 48% of their age-matched general population peers⁴⁸; a higher percentage also lives alone (41%) compared to their age-matched general population peers (12%–13%).³³ Compared to other samples of persons AwD, our cohort has the same proportion of female participants (66.7%); however, fewer individuals are married (37.8%), a higher percentage is financially poor (35%), and a greater percentage (94%) has difficulty walking or climbing steps.^8–10,45 In general, our cohort members seem to have fewer social, financial, and physical resources than those in other studies.^13–15,29

The majority of participants in our cohort (71.9%) receive SSDI. For health insurance, 58% have Medicare,⁴² and 38% have Medicaid.⁴⁹ We did not find comparable data for SSDI, Medicare, and Medicaid rates in studies with cross-diagnosis AwD samples to compare our results against. Given the low employment rate of our sample, we reviewed SSDI receipt and determined that 88% are insured by Medicare and 43% by Medicaid. At the time of baseline data collection, the state of Missouri, where most participants reside, had not passed the Affordable Care Act’s Medicaid expansion programs,⁵⁰ suggesting that some participants may have forgone employment in order to retain public health insurance through traditional Medicaid state guidelines.⁵¹

Our participants experience common AwD symptoms found in the four studies we identified. For example, using a PROMIS Pain measure in a sample of persons with neurological conditions, Molton et al.⁴⁵ found scores of 51.9 for persons aged 45–54 and 51.6 for persons aged 55–64. Using a PROMIS Fatigue measure with the same dataset, Cook et al.³⁶ found mean scores ranging from 52.4–58.7, similar to our cohort’s mean score. Amtmann et al.³⁹ used a PROMIS measure, and Jensen et al.⁵² used the PHQ-9 (Patient Health Questionnaire-9),⁵³ and both found elevated depression levels compared to the US general population; we found this too. Based on these comparisons, we have confidence that our cohort does reflect the AwD population in regard to the presence of common AwD symptoms as we understand it at this time. We did not find comparable data for self-rated physical and mental health. Although there were some significant differences between age groups in demographics, including employment, this was not the case for health and function, where age group membership was not significant.

Our analysis of social roles and social activities had similar results to those found in the Aging and Quality of Life Survey and other studies of diagnostic-specific populations^9,11,54 examining ability to participate and satisfaction with participation. We believe the similarity in findings related to AwD symptoms demonstrates that our cohort is representative of the AwD population. Quite notable, though, is our finding that social participation scores are higher for Black/African American participants compared to White cohort members. We will continue to explore this difference in future analyses.

Conclusions

We believe that our cohort reflects the AwD population and can be considered an AwD sample comparable to those found in existing literature. The findings from this analysis add to the growing body of research that can be used to both better understand AwD in midlife and inform the design of intervention studies and programs aimed at facilitating participation. Our future analyses will further explore social participation, as well as interactions among disability status and chronic health conditions, incidence of falls, influence of environmental factors on participation, engagement in life activities, and associations between use of long-term services and participation for persons AwD. These findings add to the growing body of knowledge about what common traits AwD study populations may have.

Data availability