Traumatic brain injury (TBI) is considered to be the signature injury of our current wars with over 20% of our military service members experiencing at least one TBI exposure during deployment. Persons with TBI often suffer significant functional and neurological morbidity requiring informal caregivers to assume responsibility for the individual's familial, social and financial obligations. Although research investigating the health of TBI informal caregivers is sparse, literature consistently indicates that, in general, caregivers are at risk for developing depression, anxiety, altered immune function, health problems, and poor quality of life. Recent evidence demonstrates that chronic stress leads to loss of ability of cortisol to attenuate stress-induced release of inflammatory cytokines. This may increase the risk for developing inflammatory-related disease.
The purpose of this pilot project was to assess the feasibility of using self-report data collection instruments and collecting of saliva samples for the measurement of diurnal cortisol and inflammatory cytokines in a sample of informal caregivers of TBI military service members and veterans. Findings from this pilot study will be used to determine feasibility of selected measures in the TBI informal caregiver population in evaluating a tailored intervention using a randomized controlled trial (RCT) to reduce stress and improve the health of informal caregivers of TBI military service members and veterans.
The primary aim of this study was to explore, guided by the Adapted Pittsburgh Mind Body Center Model for TBI Caregivers, caregiver and recipient characteristics, caregiver psychological and behavioral responses to stress (health promotion behavior and health care utilization), physiological measures (cortisol and cytokines), perceived health, and quality of life and the relationships among these variables in a sample of women providing informal care to a Veteran with a moderate or severe traumatic brain injury.
(1) Assess recruitment strategies and response rates for a sample of informal caregivers of moderate or severe traumatic brain injured military service members and veterans.
(2) Evaluate the feasibility of collecting saliva for the measurement of diurnal salivary cortisol, interleukin -1 receptor antagonist (IL-1ra), interleukin-6 (IL-6), interleukin-17 (IL-17), and tumor necrosing factor-alpha (TNF-alpha) via the mail from caregivers.
(3) Evaluate the feasibility of self-report questionnaire to assess health care utilization in the TBI caregiver population.
A prospective, cross-sectional, correlational methodology was used. A convenience sample of 49 women providing care for a military service member or Veteran who experienced a moderate or severe TBI within the past one to ten years was enrolled. Participants completed a written questionnaire booklet which included a sociodemographics survey and instruments measuring executive, behavioral, and emotional functioning of the care recipient (Key Behaviors Change Inventory), perceived social support (Social Provisions Scale), health history (adapted from Behavioral Risk Factor Surveillance System Survey), perceived stress (Perceived Stress Scale [PSS]), anxiety (Beck Anxiety Inventory), depressive symptoms (Center for Epidemiologic Studies Depression tool [CES-D]), grief (Hogan Grief Checklist), caregiver burden (Caregiver Reaction Assessment), health care utilization (Froelicher's Health Services Utilization Questionnaire), perceived health (SF12v2), somatic symptoms (Patient Health Questionnaire - 15), and quality of life (Ferrans and Powers Quality of Life Index - Generic Version). In addition, participants collected saliva samples to measure diurnal variation in salivary cortisol 5 times during the day (upon awakening, 30 minutes after awakening, midday, late afternoon, and at bedtime) for two consecutive days. Further, salivary cytokines (IL-6, IL-17, and TNF-alpha) were assessed in the morning saliva samples for two consecutive days.
Data Analysis: Descriptive statistics were used to summarize demographic and key variables. Partial correlation was used to examine relationships among key variables as well as linear regression to identify predictors of quality of life.
Of the 49 participants enrolled, 48 (mean age= 44) identified themselves as either a wife or significant other of the care recipient. The majority of participants was married (91.7%), White (77.1%), had completed college (54.2%), and reported an annual household income of less than $75,000 (70.8%). Key findings include participants reporting high levels of perceived stress (PSS M=20.5,SD 8.38, range 0-36) and moderate levels of depressive symptoms (CES-D M=20.63, SD 13.9, range 1-54) and anxiety (BAI M=13.97, SD 9.34, range 0-42). Further, findings revealed modest QOL levels (M=18.6 SD 0.9, range 4.7-28.0), moderate levels of caregiver burden including lack of family support (M=2.7 SD 0.9, range 1.2-5.0), financial burden (M=3.1 SD 1.0, range 1.0-5.0), impact on schedule (M=3.6 SD 0.8, range 1.4-5.0), and impact on health (M=2.7 SD .80, range 1.0-4.8). Esteem caregiver burden scores were high, suggesting that caregivers valued their caregiving role (M=4.06 SD 0.63, range 2.7-5.0). In addition, participants reported moderate levels of feelings of grief and loss, including panic behavior (M=2.35 SD .69), disorganization (M=2.3 SD .80), and detachment (M=2.10 SD .90). Age, hours of caregiving per week, duration of caregiving role, employment status, completion of college degree, caregiver burden, and perceived stress predicted QOL (p<.001) and explained 72% of its variance (adjusted r2=.72), F(11,38)=10.03. However, only the caregiver burden subscale of esteem (p=.007) and perceived stress (p=.001) were significant predictors in the regression model.
Of the 48 participants, 40 provided analyzable saliva samples. Key findings related to cortisol and cytokine measures include: (1) controlling for age, body mass index, duration of caregiving, and number of caregiving hours per week, low levels of mean cortisol awakening rise (CAR) was correlated with high levels of perceived stress (CAR) (r=-.522, p=.007) and high panic behavior(r=-.489, p=.013) and (2) Higher levels of TNF-alpha were correlated with high levels of detachment (r=.436, p=.030) and blame and anger (r=.480, p=.015). There were no significant findings related to IL-6 or IL-17.
In regards to the secondary aims of the study (1) We successfully recruited our sample in 6 months using a variety of recruitment methods including Facebook, (2) Participants did not report any difficulties collecting and mailing saliva cytokines. Further the majority of saliva samples were analyzable, and (3) The Froelicher's Health Services Utilization Questionnaire captured utilization of healthcare use during the previous month.
Findings support the need to develop interventions to decrease stress and improve the health of informal caregivers of Veterans with TBI.
- Saban KL. New Research on Caregiving in Military Families. Paper presented at: Beyond the Yellow Ribbon Teacher and Counselor Annual Symposium; 2011 Nov 4; Grove Village, IL.