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Role of Social Support in Predicting Caregiver Burden

      Abstract

      Rodakowski J, Skidmore ER, Rogers JC, Schulz R. Role of social support in predicting caregiver burden.

      Objective

      To examine the unique contribution of social support to burden in caregivers of adults aging with spinal cord injury (SCI).

      Design

      Secondary analyses of cross-sectional data from a large cohort of adults aging with SCI and their primary caregivers.

      Setting

      Multiple community locations.

      Participants

      Caregivers of community-dwelling adults aging with SCI (n=173) were interviewed as part of a multisite randomized controlled trial. The mean age ± SD of caregivers was 53±15 years and of care-recipients, 55±13 years.

      Interventions

      Not applicable.

      Main Outcome Measures

      The primary outcome was caregiver burden measured with the Abridged Version of the Zarit Burden Interview. A hierarchical multiple regression analysis examined the effects of social supports (social integration, received social support, and negative social interactions) on burden in caregivers of adults aging with SCI while controlling for demographic characteristics and caregiving characteristics.

      Results

      After controlling for demographic characteristics and caregiving characteristics, social integration (β̂=−.16, P<.05), received social support (β̂=−.15, P<.05), and negative social interactions (β̂=.21, P<.01) were significant independent predictors of caregiver burden.

      Conclusions

      Findings demonstrate that social support is an important factor associated with burden in caregivers of adults aging with SCI. Social support should be considered for assessments and interventions designed to identify and reduce caregiver burden.

      Key Words

      List of Abbreviations:

      ADL (activity of daily living), IADL (instrumental activity of daily living), SCI (spinal cord injury), VIF (variance inflation factor)
      LIFE EXPECTANCY AFTER spinal cord injury (SCI) has increased, lengthening the duration of the caregiving relationship, potentially contributing to high levels of caregiver burden. Levels of burden have implications for the health and well-being of the caregiver as well as the individual with the SCI (care-recipient).
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      Coping with spinal cord injury: personal and marital adjustment in the Hong Kong Chinese setting.
      For instance, burden is associated with poor life satisfaction, morbidity, and mortality.
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      Effects of the TCARE(R) intervention on caregiver burden and depressive symptoms: preliminary findings from a randomized controlled study.
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      Effects of Alzheimer caregiving on allostatic load.
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      Spouse caregivers of Alzheimer patients: problem responses to caregiver burden.
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      Caregiving as a risk factor for mortality: the Caregiver Health Effects Study.
      A close examination of the factors influencing burden is therefore necessary to identify caregivers at risk for poor outcomes and potential targets for interventions designed to preserve the health of the caregiving relationship.
      Theoretical models of caregiving emphasize that care-recipient functional status is the primary stressor in the caregiving experience.
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      Family caregiving in chronic illness: Alzheimer's disease, cancer, heart disease, mental illness, and stroke.
      This is consistent with empirical evidence demonstrating that compromised care-recipient functional status predicts negative outcomes.
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      • Stull D.E.
      • Borgatta E.F.
      Measurement and the analysis of burden.
      • Schulz R.
      • Tompkins C.A.
      • Wood D.
      • Decker S.
      The social psychology of caregiving: physical and psychological costs to providing support to the disabled.
      Additional caregiving characteristics directly influencing burden are the residential status of the caregiver/care-recipient dyad (eg, co-residing or residing separately) and the presence or absence of in-home support services (eg, home health aides).
      • Croog S.H.
      • Burleson J.A.
      • Sudilovsky A.
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      Spouse caregivers of Alzheimer patients: problem responses to caregiver burden.
      • Schulz R.
      • Beach S.R.
      Caregiving as a risk factor for mortality: the Caregiver Health Effects Study.
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      Predictors of caregiver burden in caregivers of individuals with dementia.
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      Enhancing the quality of life of dementia caregivers from different ethnic or racial groups: a randomized, controlled trial.
      Furthermore, demographic characteristics of the caregiver (age, sex, race, health status) and care-recipient (age) may also influence burden.
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      • Burleson J.A.
      • Sudilovsky A.
      • Baume R.M.
      Spouse caregivers of Alzheimer patients: problem responses to caregiver burden.
      • Schulz R.
      • Beach S.R.
      Caregiving as a risk factor for mortality: the Caregiver Health Effects Study.
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      • Rose K.
      • Kim S.
      Predictors of caregiver burden in caregivers of individuals with dementia.
      • Belle S.H.
      • Burgio L.
      • Burns R.
      • et al.
      Enhancing the quality of life of dementia caregivers from different ethnic or racial groups: a randomized, controlled trial.
      These factors also contribute to burden among caregivers of individuals with SCI (for care-recipients of all ages). Post et al
      • Post M.W.
      • Bloemen J.
      • de Witte L.P.
      Burden of support for partners of persons with spinal cord injuries.
      report that older age, female sex, lower care-recipient functional status, and more recent SCI onset are predictors of caregiver burden. Dickson et al
      • Dickson A.
      • O'Brien G.
      • Ward R.
      • Flowers P.
      • Allan D.
      • O'Carroll R.
      Adjustment and coping in spousal caregivers following a traumatic spinal cord injury: an interpretative phenomenological analysis.
      report that in-home support services are perceived negatively by caregivers because of feelings of inadequacy and loss of environmental control. Furthermore, high levels of burden are associated with compromised caregiver health and social isolation. Conversely, positive aspects of caregiving reduce the negative effects of caregiving and decrease burden.
      • Dickson A.
      • O'Brien G.
      • Ward R.
      • Flowers P.
      • Allan D.
      • O'Carroll R.
      Adjustment and coping in spousal caregivers following a traumatic spinal cord injury: an interpretative phenomenological analysis.
      Individuals aging with chronic conditions (eg, SCI) often experience co-occurring medical conditions that require high degrees of social and physical support. As they age, they are particularly vulnerable to social isolation. Consequently, caregivers of individuals with SCI often face multiple and often extreme challenges in providing adequate care and, thus, may experience increased social isolation. With increased social isolation comes decreased social support.
      Based on this information, several factors may contribute to burden in caregivers of adults aging with SCI; however, less is known about the role of social support in contributing to burden. We can glean additional information from theoretical models of caregiving. These models emphasize the importance of coping resources as a mitigator of the negative effects of stressors such as compromised care-recipient functional status. Social integration and support are consistently identified as key factors attenuating the perceived stress of the caregiver for caregivers of individuals with degenerative diseases.
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      • Schulz R.
      Family caregiving in chronic illness: Alzheimer's disease, cancer, heart disease, mental illness, and stroke.
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      Caregiving and the stress process: an overview of concepts and their measures.
      • Drentea P.
      • Clay O.J.
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      • Mittelman M.S.
      Predictors of improvement in social support: five-year effects of a structured intervention for caregivers of spouses with Alzheimer's disease.
      Social integration (family and friend networks, helping others, confidant relationships, and living arrangements) is associated with better caregiver mental and physical health and lower mortality.
      • Drentea P.
      • Clay O.J.
      • Roth D.L.
      • Mittelman M.S.
      Predictors of improvement in social support: five-year effects of a structured intervention for caregivers of spouses with Alzheimer's disease.
      • Cohen S.
      • Doyle W.J.
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      • Rabin B.S.
      • Gwaltney Jr, J.M.
      Social ties and susceptibility to the common cold.
      • Seeman T.E.
      • Berkman L.F.
      • Kohout F.
      • Lacroix A.
      • Glynn R.
      • Blazer D.
      Intercommunity variations in the association between social ties and mortality in the elderly A comparative analysis of three communities.
      • House J.S.
      • Landis K.R.
      • Umberson D.
      Social relationships and health.
      • Berkman L.F.
      • Glass T.
      • Brissette I.
      • Seeman T.E.
      From social integration to health: Durkheim in the new millennium.
      • Olsen R.B.
      • Olsen J.
      • Gunner-Svensson F.
      • Waldstrom B.
      Social networks and longevity A 14 year follow-up study among elderly in Denmark.
      Received social support (physical, emotional, and informational support) is purported to protect individuals from the pathogenic effects of life stress or burden.
      • Cohen S.
      Social relationships and health.
      Nonetheless, not all types of social interactions are beneficial.
      • Seeman T.E.
      • Bruce M.L.
      • McAvay G.J.
      Social network characteristics and onset of ADL disability: MacArthur studies of successful aging.
      Negative social interactions (criticism, neglect, and demands) compromise an individual's health and well-being.
      • Schulz R.A.
      • Albert S.M.
      Psychosocial aspects of aging.
      Thus, the contribution of social support to burden among caregivers of adults aging with SCI requires further examination, as it may be a meaningful target for future caregiving interventions. No studies have yet examined predictors of burden in caregivers of adults aging with SCI, nor have studies examined the potential effect that social support may have on these caregivers.
      • Elliott T.R.
      • Berry J.W.
      Brief problem-solving training for family caregivers of persons with recent-onset spinal cord injuries: a randomized controlled trial.
      Based on previous literature, we expect that demographic characteristics (older age, female sex, and compromised health status) and caregiving characteristics (lower care-recipient functional status and residential status) will predict burden in caregivers of adults aging with SCI. The purpose of this secondary analysis is to examine the role of social integration, received social support, and negative social interactions in predicting burden, after controlling for demographic and caregiving characteristics.

      Methods

      We conducted a secondary analysis of data from a multisite randomized controlled trial testing a caregiver and care-recipient dyadic intervention.
      • Schulz R.
      • Czaja S.J.
      • Lustig A.
      • Zdaniuk B.
      • Martire L.M.
      • Perdomo D.
      Improving the quality of life of caregivers of persons with spinal cord injury: a randomized controlled trial.
      We used cross-sectional baseline data for the current study analyses. Dyads were recruited from community locations in Pittsburgh, Pennsylvania, and Miami, Florida. Outreach efforts were extensive, including radio and television announcements, newspaper articles and advertisements, newsletter articles, and community presentations. Both sites obtained institutional review board approval, and both dyad members provided written informed consent.

      Participants

      Caregivers were included if they provided physical or emotional support for an individual with an SCI; had regular contact with the individual with the SCI; maintained the relationship for the previous 6 months; were at least 18 years of age; planned to stay in the current community for the next 6 months; had a telephone; and were fluent in English. Care-recipients were included if they acquired an SCI because of injury or disease, resulting in a complete or incomplete SCI as defined by the American Spinal Injury Association; had a mobility impairment attributable to the SCI; were at least 35 years of age; lived in a nongroup community setting for at least 1 year; planned to remain in the current community for the subsequent 6 months; had a telephone; and were competent in English. Dyads were excluded if either member of the dyad had a terminal illness (life expectancy <6mo); were in active cancer treatment other than maintenance use of tamoxifen or leuprolid; were blind or deaf; had cognitive impairment, as defined by the Short Portable Mental Status Questionnaire (≥4 errors)
      • Pfeiffer E.
      A short portable mental status questionnaire for the assessment of organic brain deficit in elderly patients.
      ; or did not meet previously stated study criteria.

      Procedures

      Potential study caregivers were screened via telephone, and if they were interested and eligible, an in-home assessment was conducted by a trained assessor. Caregivers were compensated $25 for the baseline assessment.

      Primary outcome

      Burden was measured using the Abridged Version of the Zarit Burden Interview (12 items),
      • Bedard M.
      • Molloy D.W.
      • Squire L.
      • Dubois S.
      • Lever J.A.
      • O'Donnell M.
      The Zarit Burden Interview: a new short version and screening version.
      • Zarit S.H.
      • Orr N.K.
      • Zarit J.M.
      The hidden victims of Alzheimer's disease: families under stress.
      measuring the degree to which a caregiver perceives financial, role, and personal burden from caregiving. Items were rated on a 5-point scale from 0 (never) through 4 (nearly always). We computed a total score (range, 0–48) where a higher score indicated more burden. Standardized Cronbach α was .85.

      Predictors of caregiver burden

      Caregiver and care-recipient demographic characteristics (age, sex, race, employment status) were collected to identify potential confounding factors within caregiver burden. Health status was assessed by asking caregivers and care-recipients to rate their health (1 item) on a 5-point scale (0, excellent; 4, poor). A higher score (range, 0–4) indicated a compromised health perception. A recent meta-analysis found this measure to have a statistically significant relationship between compromised health perception and mortality while controlling for functional status, depression, and comorbidities.
      • DeSalvo K.B.
      • Bloser N.
      • Reynolds K.
      • He J.
      • Muntner P.
      Mortality prediction with a single general self-rated health question.
      Caregiving characteristics were included to identify their impact on caregiver burden. Care-recipient functional status addressed both basic (activities of daily living [ADLs]) and instrumental activities of daily living (IADLs). The Katz Index of ADLs measured ADLs by assessing whether the care-recipient needed help in bathing, dressing, toileting, transfers, maintaining continence, and feeding (6 items).
      • Katz S.
      • Ford A.B.
      • Moskowitz R.W.
      • Jackson B.A.
      • Jaffe M.W.
      Studies of illness in the aged The Index of ADL: a standardized measure of biological and psychosocial function.
      Items were rated dichotomously (0, no; 1, yes). We computed a total score (range, 0–6) where a higher score indicated more assistance required in ADLs. Standardized Cronbach α was .81.
      The Instrumental Activities of Daily Living Scale measured IADLs by assessing whether the care-recipient needed help using a telephone, shopping, preparing food, housekeeping, doing laundry, obtaining transportation, managing medications, and managing finances.
      • Lawton M.P.
      • Brody E.M.
      Assessment of older people: self-maintaining and instrumental activities of daily living.
      Items were rated dichotomously (0, no; 1, yes). We computed a total score (range, 0–8) where a higher score indicated more assistance required in IADLs. Standardized Cronbach α was .79.
      We measured in-home support services by totaling the number of housekeepers, personal care attendants, transportation services, and in-home health care workers the care-recipient received (12 items). Items were rated dichotomously (0, no service received; 1, service received). We computed a total score (range, 0–12) where a higher score indicated more in-home support services.
      Positive aspects of caregiving measured the degree that caregivers felt useful, needed, appreciated, important, and confident (11 items).
      • Tarlow B.J.
      • Wisniewski S.R.
      • Belle S.H.
      • Rubert M.
      • Ory M.G.
      • Gallagher-Thompson D.
      Positive aspects of caregiving—contributions of the REACH project to the development of new measures for Alzheimer's caregiving.
      Items were rated on a 5-point scale (0, disagree a lot; 4, agree a lot). A higher computed total score (range, 0–44) indicated a greater sense of positive aspects in caregiving. Standardized Cronbach α was .86.
      Caregiving characteristics (relationship to care-recipient, dyad residential status, ie, whether or not co-residing, years living together, and level and severity of SCI) were collected to identify potential confounding factors within caregiver burden.
      Social support was included to identify its impact on caregiver burden. Lubben Social Network Index measured social integration by assessing the number of individuals the caregiver interacts with monthly, talks with comfortably, and asks assistance from easily (3 items).
      • Lubben F.
      • Ramsden J.B.
      Assessing pre-university students through extended individual investigations: teachers' and examiners' views.
      Items were rated on a 6-point scale (0, no individuals; 5, ≥9 individuals). We computed a total score (range, 0–15) where a higher score indicated more social integration. Standardized Cronbach α was .76.
      Received social support was measured using a modified version of the social support scale from the Resources for Enhancing Alzheimer's Caregiver Health (REACH I) trials.
      • Belle S.H.
      • Burgio L.
      • Burns R.
      • et al.
      Enhancing the quality of life of dementia caregivers from different ethnic or racial groups: a randomized, controlled trial.
      Received social support assessed physical (providing services or assistance), emotional (offering empathy or caring), and informational (giving advice or guidance) support (3 items). Items were rated on a 4-point scale (0, never; 3, very often). We computed a total score (range, 0–9) where a higher score indicated more received social support. Standardized Cronbach α was .47, indicating that the 3 types of support sampled likely represent different constructs.
      Negative social interactions were measured by assessing whether the caregivers felt others have made demands, been critical, pried into personal affairs, or taken advantage of them (4 items).
      • Krause N.
      Negative interaction and satisfaction with social support among older adults.
      Items were rated on a 4-point scale (0, never; 3, very often). We computed a total score (range, 0–12) where a higher score indicated more negative social interactions. Standardized Cronbach α was .81.

      Data Analyses

      We examined the distribution of the measures' scores and computed bivariate correlations among all measures using Pearson and Kendall Tau statistics. Sex, race, employment status, and dyad residential status were analyzed as dichotomous variables in the regression analysis. In addition to frequently cited factors contributing to burden, independent variables with correlations of strength r>.10 were included in the model. Subsequently, we conducted a hierarchical multiple regression analysis. Items were entered into the regression analysis according to features frequently seen in caregiving models.
      • Montgomery R.V.
      • Stull D.E.
      • Borgatta E.F.
      Measurement and the analysis of burden.
      • Schulz R.
      • Tompkins C.A.
      • Wood D.
      • Decker S.
      The social psychology of caregiving: physical and psychological costs to providing support to the disabled.
      Demographic characteristics are described as stable and unchanging, providing the foundation for the environment. Block 1 included demographic characteristics of the caregiver and care-recipient (caregiver and care-recipient age, caregiver sex, race, employment status, and caregiver and care-recipient perceived health status) (table 1). Following the caregiving models, caregiving characteristics are the primary stressors or environmental demands experienced by the caregiver. Block 2 added caregiving characteristics (care-recipient functional status [ADL and IADL status], in-home support services, positive aspects of caregiving, dyad residential status, and SCI chronicity). Block 3 isolated the contribution of social support (social integration, received social support, and negative social interactions). Finally, regression diagnostics were conducted to ensure that collinearity (variance inflation factor [VIF] was <10 and tolerance was >0.2) was not affecting the model.
      Table 1Variable Categories
      Demographic CharacteristicsCaregiving CharacteristicsSocial Support
      Age (CG/CR)ADL status (CR)Social integration (CG)
      Sex (CG)IADL status (CR)Received social support (CG)
      Race (CG)In-home support services (CR)Negative social interactions (CG)
      Employment status (CG)Positive aspects of CG (CG)
      Perceived health status (CG/CR)Dyad residential status (CG/CR)
      Chronicity of SCI (CR)
      Abbreviations: CG, caregiver; CR, care-recipient.

      Results

      In the parent study, 459 caregivers were screened, 262 were not eligible, and 24 eligible caregivers refused participation, indicating that they were not interested in study participation or were too busy. Baseline assessment was completed by 173 caregivers.
      Most of the caregivers were women (75.8%, n=131), white (74.0%, n=128), employed (50.2%, n=87), went to school beyond high school (68.2%, n=118), and were spouses to the individual with the SCI (69.3%, n=120). Their mean age ± SD was 53±15 years. Most of the care-recipients were men (65%, n=112), white (76%, n=131), unemployed (36%, n=62) or retired (36%, n=63), and went to school beyond high school (73%, n=127). Their mean age ± SD was 55±13 years. Care-recipients sustained SCI at the cervical level (51%, 35% of these were complete), thoracic level (29%, 53% of these were complete), and lumbar level (5%, 11% of these were complete). Chronicity of SCI was an average of 12 years (table 2).
      Table 2Dyad Demographics and Characteristics
      CharacteristicsCaregivers (n=173)Care-recipients (n=173)
      Age (y)53±1555±13
      Women131 (76)61 (35)
      Education
       Less than high school7 (4)9 (5)
       High school50 (29)37 (21)
       More than high school118 (68)127 (73)
      Employed
       Employed outside the home81 (47)32 (19)
       Homemaker inside the home6 (4)9 (5)
       Unemployed86 (49)132 (76)
      Race
       White128 (74)131 (76)
       African American23 (13)19 (11)
       Hispanic18 (10)17 (10)
       Other4 (2)6 (4)
      Income ($)
       <20,00025 (14)36 (21)
       20,000–39,00040 (23)37 (21)
       40,000–59,00040 (23)28 (16)
       >60,00059 (34)64 (37)
      Dyad co-residential status140 (81)
      Relationship to individual with SCI
       Spouse120 (69)
       Parent4 (2)
       Child14 (8)
       Other34 (20)
      Length of caregiving relationship (y)8±9
      Chronicity of SCI (y)12±12
      Level of SCI
       Cervical88 (51)
       Thoracic51 (29)
       Lumbar9 (5)
       Unknown25 (14)
      Severity of SCI
       Complete63 (36)
       Incomplete84 (49)
       Unknown26 (15)
      Caregiver burden (range, 0–48)
      Higher scores indicate negative outcomes.
      11.82±7.75
      Perceived health (range, 0–4)
      Higher scores indicate negative outcomes.
      1.53±1.00
      Positive aspects of CG (range, 0–44)32.82±8.60
      Social integration (range, 0–15)9.08±3.17
      Received social support (range, 0–9)2.97±1.78
      Negative interactions (range, 0–12)
      Higher scores indicate negative outcomes.
      2.35±2.44
      ADL status (range, 0–6)
      Higher scores indicate negative outcomes.
      2.85±2.07
      IADL status (range, 0–8)
      Higher scores indicate negative outcomes.
      4.28±2.36
      In-home support services (range, 0–12)2.10±1.52
      NOTE. Values are mean ± SD or n (%).
      Abbreviations: CG, caregiving; CR, care-recipient.
      low asterisk Higher scores indicate negative outcomes.

      Correlation Analyses

      Inspection of the scatterplots for burden and the independent variables revealed normal distribution and few outliers. Beyond the frequently cited factors contributing to caregiver burden, positive aspects of caregiving, dyad residential status, and SCI chronicity were correlated with burden (ie, r>.10) and included in the model. Correlation coefficients are presented in table 3. Caregiver relationship to care-recipient, care-recipient age, care-recipient perceived health status, SCI level, SCI severity, and years living together were not correlated with caregiver burden and were not included in the model.
      Table 3Correlates of Caregiver Burden
      Demographics, Caregiving Characteristics, and Social Support12345678910111213141516171819
      1. Caregiver burden (CG)
      2. Age (CR)−.04
      3. Age (CG).01.52
      P≤.01. Pearson correlations, unless noted with
      4. Sex
      (Kendall Tau correlation).
      (CG)
      −.01−.01.06
      5. Black
      (Kendall Tau correlation).
      (CG)
      −.10.05−.09−.06
      6. Hispanic
      (Kendall Tau correlation).
      (CG)
      −.04−.18
      P≤.05.
      −.21
      P≤.01. Pearson correlations, unless noted with
      .03−.13
      7. Other
      (Kendall Tau correlation).
      (CG)
      −.02−.03−.02−.09−.06−.05
      8. Employed inside home
      (Kendall Tau correlation).
      (CG)
      .06−.01−.11.11.02.04−.03
      9. Employed outside home
      (Kendall Tau correlation).
      (CG)
      .04−.35
      P≤.01. Pearson correlations, unless noted with
      −.36
      P≤.01. Pearson correlations, unless noted with
      .01.01.06.01−.18
      P≤.05.
      10. Perceived health status (CR).12.08−.07−.02.09−.11.12.02.02
      11. Perceived health status (CG).26
      P≤.01. Pearson correlations, unless noted with
      .02.12−.10.05.01−.04.12−.28
      P≤.01. Pearson correlations, unless noted with
      .03
      12. ADL status (CR).34
      P≤.01. Pearson correlations, unless noted with
      .05.03−.08.01−.06−.03.01−.03−.03−.02
      13. IADL status (CR).33
      P≤.01. Pearson correlations, unless noted with
      .07−.02.00.06−.02−.03.06.02.09−.01.59
      P≤.01. Pearson correlations, unless noted with
      14. In-home support services (CR).24
      P≤.01. Pearson correlations, unless noted with
      .03.02.06.02.07−.01.01.08.15−.01.41
      P≤.01. Pearson correlations, unless noted with
      .46
      P≤.01. Pearson correlations, unless noted with
      15. Positive aspects of CG (CG)−.31
      P≤.01. Pearson correlations, unless noted with
      −.01−.13−.09.13.12.03−.01.04.01−.10.02.06.04
      16. Dyad residential status
      (Kendall Tau correlation).
      (CG/CR)
      .21
      P≤.01. Pearson correlations, unless noted with
      .06.11.14−.20
      P≤.01. Pearson correlations, unless noted with
      −.08−.02.01−.16
      P≤.05.
      −.05−.04.09−.04−.23
      P≤.01. Pearson correlations, unless noted with
      −.19
      P≤.01. Pearson correlations, unless noted with
      17. Chronicity of SCI (CR)−.18
      P≤.05.
      −.01−.05−.02−.05.02.13−.04.06.02−.18
      P≤.05.
      −.15
      P≤.05.
      −.24
      P≤.01. Pearson correlations, unless noted with
      −.11.14.08
      18. Social integration (CG)−.20
      P≤.01. Pearson correlations, unless noted with
      −.08.08.03−.19
      P≤.01. Pearson correlations, unless noted with
      −.22
      P≤.01. Pearson correlations, unless noted with
      −.11−.03.09.08−.06.00−.09−.06−.09−.01−.03
      19. Received social support (CG)−.21
      P≤.01. Pearson correlations, unless noted with
      −.21
      P≤.01. Pearson correlations, unless noted with
      −.08−.13−.04−.08.09−.09.06.20
      P≤.01. Pearson correlations, unless noted with
      .03.04.05.20
      P≤.01. Pearson correlations, unless noted with
      .18
      P≤.05.
      −.27
      P≤.01. Pearson correlations, unless noted with
      .00.35
      P≤.01. Pearson correlations, unless noted with
      20. Negative social interactions (CG).20
      P≤.01. Pearson correlations, unless noted with
      −.01−.30
      P≤.01. Pearson correlations, unless noted with
      −.22
      P≤.01. Pearson correlations, unless noted with
      .11.04−.05.04.00−.10.15
      P≤.05.
      −.02.06.13.01−.20
      P≤.01. Pearson correlations, unless noted with
      −.08−.08.12
      Abbreviations: CG, caregiver; CR, care-recipient.
      low asterisk P≤.01. Pearson correlations, unless noted with
      (Kendall Tau correlation).
      P≤.05.

      Hierarchical Multiple Regression Analysis

      Hierarchical multiple regression analysis findings are shown in table 4. The model's average VIF was 1.40, and the tolerance ranged between .51 and .91, indicating no collinearity among predictors. Refer to table 1 for variables within each block. In block 1, demographic characteristics contributed 7% of the variance in caregiver burden. In block 2, after controlling for demographic characteristics, caregiving characteristics contributed an additional 26% of the variance. In block 3, after controlling for demographic characteristics and caregiving characteristics, social support contributed an additional 9% of the variance in caregiver burden (F199,170=7.72; R2adj=.43, P<.01).
      Table 4Hierarchical Multiple Regression
      Block 1: Demographicsβ̂PBlock 2: Demographics and Caregiving Characteristicsβ̂PBlock 3: Demographics, Caregiving Characteristics, and Social Supportβ̂P
      Intercept.17Intercept.21Intercept.15
      Age (CR)−.05.55Age (CR)−.06.43Age (CR)−.04.56
      Age (CG).07.45Age (CG).04.68Age (CG).09.27
      Sex (CG)−.02.85Sex (CG)−.07.32Sex (CG)−.04.54
      White (ref.)NANAWhite (ref.)NANAWhite (ref.)NANA
      Black (CG)−.12.12Black (CG)−.05.47Black (CG)−.11.09
      Hispanic (CG)−.05.53Hispanic (CG).00.99Hispanic (CG)−.06.39
      Other (CG)−.03.65Other (CG).00.99Other (CG).01.89
      Unemployed (ref)NANAUnemployed (ref)NANAUnemployed (ref)NANA
      Employed inside home (CG).09.25Employed inside home (CG).07.28Employed inside home (CG).07.28
      Employed outside home (CG).17.06Employed outside home (CG).18.02Employment outside home (CG).23.00
      Perceived health status (CR).14.07Perceived health status (CR).11.10Perceived health status (CR).07.30
      Perceived health status (CG).29.00Perceived health status (CG).28.04Perceived health status (CG).26.00
      ADL status (CR).14.10ADL status (CR).17.03
      IADL status (CR).17.04IADL status (CR).15.06
      In-home support services (CR).16.05In-home support services (CR).15.05
      Positive aspects of CG (CG)−.24.00Positive aspects of CG (CG)−.21.00
      Dyad residential status (CG/CR).28.00Dyad residential status (CG/CR).26.00
      Chronicity of SCI (CR)−.05.44Chronicity of SCI (CR)−.05.45
      Social integration (CG)−.16.02
      Received social support (CG)−.15.03
      Negative social interactions (CG).21.00
      Abbreviations: CG, caregiver; CR, care-recipient; NA, not applicable; ref, referent.
      Caregiver perceived health status (β̂=.26, P<.01) explained the largest amount of variance in caregiver burden, followed by dyad residential status (β̂=.26, P<.01), employment outside the home (β̂=.23, P<.01), negative social interactions (β̂=.21, P<.01), positive aspects of caregiving (β̂=−.21, P<.01), care-recipient ADL status (β̂=.17, P<.05), social integration (β̂=−.16, P<.05), received social support (β̂=−.15, P<.05), and in-home support services based on standardized beta scores.

      Discussion

      Our primary focus was to examine the contribution that social support makes to burden in caregivers of adults aging with SCI, as social support is associated with health and burden.
      • Cohen S.
      • Doyle W.J.
      • Skoner D.P.
      • Rabin B.S.
      • Gwaltney Jr, J.M.
      Social ties and susceptibility to the common cold.
      • Seeman T.E.
      • Berkman L.F.
      • Kohout F.
      • Lacroix A.
      • Glynn R.
      • Blazer D.
      Intercommunity variations in the association between social ties and mortality in the elderly A comparative analysis of three communities.
      • House J.S.
      • Landis K.R.
      • Umberson D.
      Social relationships and health.
      • Cohen S.
      Social relationships and health.
      • Schulz R.A.
      • Albert S.M.
      Psychosocial aspects of aging.
      Considering the number of factors that could predict burden, social support contributed meaningfully to the variance in burden.
      • Ferguson C.J.
      An effect size primer: a guide for clinicians and researchers.
      We discovered that higher levels of social integration and received social support were associated with lower burden in caregivers of adults aging with SCI, affirming other gerontology studies that reported that social integration promoted health
      • Cohen S.
      • Doyle W.J.
      • Skoner D.P.
      • Rabin B.S.
      • Gwaltney Jr, J.M.
      Social ties and susceptibility to the common cold.
      • Seeman T.E.
      • Berkman L.F.
      • Kohout F.
      • Lacroix A.
      • Glynn R.
      • Blazer D.
      Intercommunity variations in the association between social ties and mortality in the elderly A comparative analysis of three communities.
      • House J.S.
      • Landis K.R.
      • Umberson D.
      Social relationships and health.
      and received social support reduced stress.
      • Berkman L.F.
      • Glass T.
      • Brissette I.
      • Seeman T.E.
      From social integration to health: Durkheim in the new millennium.
      • Cohen S.
      Social relationships and health.
      However, not all social interactions were reported as positive.
      • Seeman T.E.
      • Bruce M.L.
      • McAvay G.J.
      Social network characteristics and onset of ADL disability: MacArthur studies of successful aging.
      Members of one's social network may mean well, but they can also be demanding, thereby adversely impacting health outcomes.
      • Schulz R.A.
      • Albert S.M.
      Psychosocial aspects of aging.
      We observed strong relationships between negative social interactions and burden, suggesting that interventions mitigating negative interactions while enhancing social integration and support may be particularly important.
      In addition to the contribution of social support, a number of similarities between our findings and other caregiving studies were found. Consistent with studies examining caregiving of individuals with SCI, caregiver health status was associated with higher levels of burden.
      • Post M.W.
      • Bloemen J.
      • de Witte L.P.
      Burden of support for partners of persons with spinal cord injuries.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
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      • Dreer L.E.
      • Elliott T.R.
      • Shewchuk R.
      • Berry J.W.
      • Rivera P.
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      Caregivers with compromised health may find it more difficult to complete caregiving tasks because of their own physical or psychological limitations. Additionally, we found that co-residing with the care-recipient strongly predicted burden. Caregivers of individuals with degenerative diseases have described limited relief from caregiving while living with the care-recipient.
      • Schulz R.
      • O'Brien A.T.
      • Bookwala J.
      • Fleissner K.
      Psychiatric and physical morbidity effects of dementia caregiving: prevalence, correlates, and causes.
      Several recent gerontology studies suggested that daily exposure to the suffering of a close friend or relative, such as would be the case when the dyad is co-residing, was associated with burden and depression.
      • Schulz R.
      • Hebert R.S.
      • Dew M.A.
      • et al.
      Patient suffering and caregiver compassion: new opportunities for research, practice, and policy.
      • Cassell E.J.
      The nature of suffering and the goals of medicine.
      • Ferrell B.
      • Coyle N.
      The nature of suffering and the goals of nursing.
      We discovered that positive aspects of caregiving were associated with burden. Caregivers who reported that caregiving made them feel useful, needed, important, and confident reported lower levels of burden, demonstrating the potential positive effect of a caregiver's psychological approach. Caregivers of individuals with SCI reported that focusing on the positive aspects was an effective coping mechanism.
      • Dickson A.
      • O'Brien G.
      • Ward R.
      • Flowers P.
      • Allan D.
      • O'Carroll R.
      Adjustment and coping in spousal caregivers following a traumatic spinal cord injury: an interpretative phenomenological analysis.
      Previous studies
      • Post M.W.
      • Bloemen J.
      • de Witte L.P.
      Burden of support for partners of persons with spinal cord injuries.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
      The impact of being a support provider to a person living in the community with a spinal cord injury.
      • Dreer L.E.
      • Elliott T.R.
      • Shewchuk R.
      • Berry J.W.
      • Rivera P.
      Family caregivers of persons with spinal cord injury: predicting caregivers at risk for probable depression.
      examining caregiving of individuals with SCI found care-recipient functional status to be a predictor of burden and compromised quality of life. We also demonstrated that care-recipient functional status (ADL status) predicted burden for caregivers of adults aging with SCI. However, we found that IADL status did not predict burden, and level and severity of the SCI were not associated with burden, yet higher levels of SCI and IADL status were significantly associated with use of in-home support services (r=−.16, P<.05; r=.46, P<.01, respectively). Thus, burden may be reflected in the use of in-home support services, which was found to predict burden.
      Differences between our findings and the findings of other caregiving studies were found. Caregivers employed outside the home reported higher burden. No other studies have examined employment's contribution to burden in caregivers of individuals with SCI, but this finding has been reported in other caregiving populations.
      • Duxbury L.
      • Higgins C.
      • Smart R.
      Elder care and the impact of caregiver strain on the health of employed caregivers.
      Employment outside the home may be associated with burden because of competing work and caregiving roles. Caregivers may find it difficult to disassociate from their caregiving role while at work.
      Caregivers and care-recipients were, on average, in their mid-50s. However, caregiver demographic characteristics (age, sex, race) were not significant predictors of burden. While these factors have been shown to be important in other SCI samples,
      • Post M.W.
      • Bloemen J.
      • de Witte L.P.
      Burden of support for partners of persons with spinal cord injuries.
      • Boschen K.A.
      • Tonack M.
      • Gargaro J.
      The impact of being a support provider to a person living in the community with a spinal cord injury.
      • Dreer L.E.
      • Elliott T.R.
      • Shewchuk R.
      • Berry J.W.
      • Rivera P.
      Family caregivers of persons with spinal cord injury: predicting caregivers at risk for probable depression.
      they appear to be less important for caregivers of adults aging with SCI. Additionally, despite the large variability in care-recipient age, SCI chronicity, and health status, none significantly predicted caregiver burden. Potentially, care-recipient demographics and SCI chronicity cease to be important after caregivers completed the postacute adjustment phase (approximately 6mo).

      Study Limitations

      Several study limitations should be acknowledged. The dyads' education level is fairly high, and therefore the sample may not be representative of the population of caregivers of adults aging with SCI. Also, we conducted a cross-sectional analysis, so caution is advised in making causal interpretations of findings. It is possible that caregivers with high levels of burden are more likely to perceive negative social interactions, or alternatively, are more likely to generate negative social interactions because of their burden. To address these issues, longitudinal studies are needed. Conversely, this study has many strengths, including a large, distinct sample and a comprehensive analytic approach that allows for assessment of the independent effects of social support. Our findings provide a firm foundation for future studies of caregivers of adults aging with SCI.

      Conclusions

      In summary, caregiver's perceived health status, residential status, employment outside the home, perceived positive aspects of caregiving, care-recipient functional status (ADL and IADL status), in-home support services, and social support appear to strongly influence caregiver burden. Negative social interactions, among social support, most strongly predicted burden. With knowledge of these predictors, further examination of their impact on caregivers of adults aging with SCI may be useful for identifying ways to improve caregiver health and inform interventions.

      Acknowledgment

      We thank Sara Czaja, PhD, at the University of Miami Miller School of Medicine who contributed to the development and implementation of the parent-study.

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