Longitudinal Examination of Mood Disturbance, Inflammation and Acute Illness Outcomes in Spousal Alzheimer's Disease Caregivers

Includes bibliographical references (pages 76-90).Over 15 million Americans provide unpaid care for a family member with Alzheimer's disease. Dementia caregiving can have detrimental effects on caregivers' physical health, including increased risk for cardiovascular disease (CVD) and mortality. Inflammation, evidenced by elevated plasma interleukin-6 (IL-6) and C-reactive protein (CRP), may play a fundamental role in the initiation and progression of CVD. Dementia caregivers may also be at increased risk for acute illness or infection, such as cold or flu. Evidence suggests that caregivers with mood disturbance may be particularly vulnerable to these health outcomes. Existing research indicates that depression is linked with both elevated inflammation and increased CVD risk, and may also be associated with immune dysfunction and susceptibility to acute illness. Caregivers experience greater mood disturbance compared with noncaregivers, but investigation of the relationship between mood disturbance and health outcomes in caregivers has been minimal and largely cross-sectional. The present study addresses gaps in the current literature by using mixed models regression to investigate associations between\ud xii\ud mood disturbance [i.e., depressive symptoms, positive affect (PA), and negative affect (NA)] and caregiver health (i.e., inflammation and symptoms of acute illness) over time. Spousal caregivers (N=116) completed annual in-home assessments for up to five years, including a semi-structured psychosocial interview and blood draw. Caregivers were primarily female (69.0%) and Caucasian (87.9%) with a mean age of 74.6 years (SD=7.8). Multilevel analyses revealed that caregivers with higher average levels of NA over the course of the study had higher levels of IL-6 and CRP. No other mood predictors were significantly related to inflammation, including within-caregiver yearly fluctuations in mood. With regard to acute illness symptoms, caregivers with higher average levels of depressive symptoms and NA throughout the study were significantly more likely to report flu symptoms. Yearly fluctuations in depressive symptoms within caregivers were also associated with higher likelihood of experiencing flu symptoms. This study provides preliminary evidence that mood disturbance, particularly increased NA, is associated with inflammation and acute illness symptoms in dementia caregivers. Chronic mood disturbance appeared to have a stronger association with caregiver health, highlighting the need for timely intervention to treat caregiver mood disturbance