Who Matters? The Effects of Sources of Social Support on Quality of Life in Prostate Cancer Survivors and Their Spousal Caregivers

of a dissertation at the University of Miami Dissertation co-supervised by Professors Youngmee Kim and Frank J. Penedo. No. of pages in text. (142) Improvements in public awareness and in regular screening for prostate cancer (PC) have resulted in dramatic increases in survival for men diagnosed with localized stage disease. However, this has resulted in a significant, and growing, population of men, who are now placed in the difficult position of having to find ways to cope with the physical and mental challenges that can develop following their diagnosis. Existing literature suggests that positive social support can act to help PC survivors adjust physically and mentally to the disease. Historically, the social support construct has been separated into two primary forms: 1) structural support, which describes the quantity and framework of an individual’s support network and 2) functional support, which describes the quality of the support that the individual perceives. Several salient sources of support have been identified, with the individual’s spouse most often noted as being the primary caregiver for PC survivors. Although the long-term task of caregiving for a PC survivor can be especially challenging, little research has investigated the adjustment process of spousal caregivers of PC survivors. The limited research which has evaluated quality of life outcomes in these populations has primarily done so independently of one another, rather than considering the two groups as a dyadic unit. The current study proposed to address several key limitations of our current knowledge by: 1) document the levels and relationships among physical and mental quality of life and sources of social support in the understudied populations of PC survivors and their spousal caregivers and 2) evaluate the effects of different sources of social support on physical and psychological quality of life in a dyadic model that considers both survivor and caregiver functioning. Results from the current study suggest that both the PC survivor and his spousal caregiver report lower than normative levels of significant other support, while the spousal caregiver reported lower than normative levels of family and friend support, as well. The specified actor-partner interdependence model indicated that for the PC survivor his perceptions of significant other support were significantly related to his level of physical quality of life (β=.33, p<.05) and his perceptions of friend support were significantly related to his level of mental quality of life (β=.43, p<.05). For the spousal caregiver, her perceptions of friend support were significantly associated with her level of mental quality of life (β=.38, p<.05). The introduction of age into the model, as a co-variate of physical and mental quality of life, did not affect the relationships between sources of support and quality of life. However, the introduction of age and number of medical co-morbidities into the model, as co-variates of physical and mental quality of life, caused the relationship between PC survivor significant other support with his physical quality of life to become non-significant. These results indicate that unique sources of social support have implications in the adjustment process for PC survivors and their spousal caregivers and are valuable targets for future psychosocial intervention work designed to influence their quality of life. TABLE OF CONTENTS Page CHAPTER 1: INTRODUCTION. 1 Prostate Cancer. 1 Treatments for Prostate Cancer . 4 Quality of Life of Prostate Cancer Survivors. 6 Quality of Life of Spousal Caregivers of Prostate Cancer Survivors . 8 Caregiving . 8 Spousal Caregivers . 10 A Neglected Population: Prostate Cancer Spousal Caregivers . 12 Dyadic Mutuality of Prostate Cancer Adjustment . 14 Dyadic Coping for Prostate Cancer Survivors and Their Spousal Caregivers. 19 Social Support . 23 Structural Social Support and Quality of Life. 24 Sources of Support. 26 Functional Social Support and Quality of Life . 30 Negative Support . 33 Gender Effects. 34 Integration of Structural and Functional Support. 35 Limitations of Existing Literature and Current Study. 37 Establishing Actor-Partner Interdependence Model. 39 Covariates Associated with Study Outcomes. 43 Study Aims and Hypotheses . 43 Specific Aim 1 . 43 Specific Aim 2 . 44 Specific Aim 3 . 45 Specific Aim 4 . 47 CHAPTER 2: METHODS. 48 Participants . 48 Measures. 50 Sources of Social Support. 50 Quality of Life . 51 Study Sample Covariates. 52 Statistical Analysis Plans . 52 Preliminary Analyses. 52 Testing Study Aims and Hypotheses . 53 Specific Aim 1 . 53 Specific Aim 2 . 54 Specific Aim 3 . 55