Social Isolation, Vital Exhaustion, and Incident Heart Failure
Social Isolation, Vital Exhaustion, and Incident Heart Failure
Aims Prospective studies have shown that social isolation (i.e. lack of social contacts) predicts incident coronary heart disease (CHD), but it is unclear whether it predicts incident heart failure (HF) and what factors might mediate this association. HF patients may be more susceptible to social isolation as they tend to be older and may have disrupted social relationships due to life course factors (e.g. retirement or bereavement). We prospectively examined whether individuals with higher vs. low social isolation have a higher incidence of HF and determined whether this association is mediated by vital exhaustion.
Methods and results We estimated incident HF hospitalization or death among 14 348 participants from Visit 2 (1990–1992) in the Atherosclerosis Risk in Communities (ARIC) study using Cox proportional hazard models which were sequentially adjusted for age, race/study community, gender, current smoking, alcohol use, and co-morbidities. We conducted mediation analyses according to the Baron and Kenny method. After a median follow-up of 16.9 person-years, 1727 (13.0%) incident HF events occurred. The adjusted hazard of incident HF was greater for those in the higher vs. low social isolation risk group (hazard ratio 1.21, 95% confidence interval 1.08–1.35). Our data suggest that vital exhaustion strongly mediates the association between higher social isolation and incident HF (the percentage change in beta coefficient for higher vs. low social isolation groups after adjusting for vital exhaustion was 36%).
Conclusion These data suggest that greater social isolation is an independent risk factor for incident HF, and this association appears to be strongly mediated by vital exhaustion.
Heart failure (HF) is a complex disease which represents the final common pathway for many diseases of the heart. HF affects ~6 million Americans, with US$37 billion in direct costs. It is a major cause of morbidity and mortality and thus is considered by policymakers as a high priority condition. As the population ages and therapeutic advances result in greater survival after acute cardiac events, the incidence of HF will continue to rise.
Social relationships affect the aetiology and prognosis of cardiovascular diseases (CVDs), and extant research often operationalizes social relationships through the concepts of social support and integration. Social support refers to the quantity and quality of resources (e.g. emotional, tangible, and informational) available through social interactions with others. Social integration reflects the number and types of social ties to others (e.g. marital status, amount of family and friend contact, and group membership). Although related, social support and integration are distinct concepts with only moderate correlations. Social integration is thought to protect or enhance health by providing a source of generalized positive affect which reduces psychological distress, enhances one's motivation for self-care, suppresses neuroendocrine responses, and enhances immune function. Conversely, lack of social integration (i.e. social isolation) is considered a 'stressor', inducing a negative psychological state which can increase neuroendocrine responses, suppress immune function, and interfere with performance of health-promoting behaviours. Over time, social isolation may lead to vital exhaustion, which is defined by excessive fatigue, feelings of demoralization, and increased irritability, and is considered an adaptation to prolonged psychological distress. Vital exhaustion is conceptually related to depression, and some studies report a correlation coefficient as high as 0.76 between measures of vital exhaustion and depression. However, guilt and low self-esteem—key features of depression—are largely absent among exhausted persons. Previous studies show a positive association between vital exhaustion and incident cardiac events.
Social support and social networks have also been shown to predict incident coronary heart disease (CHD) in five of eight long-term prospective studies reviewed. Although important, CHD causes only about half of the cases of incident HF in the general population under age 75, so it is worthwhile also to examine whether social relationships predict incident HF. However, few studies have specifically examined the association between social isolation and incident HF even though HF patients tend to be older and may have disrupted social relationships due to life-course factors, such as retirement and bereavement. Further, little is known about the potential mediators of this association. Vital exhaustion is one potential mediator of the association between social isolation and incident HF. Therefore, the objectives of this study were to: (i) prospectively examine whether individuals at higher vs. low risk for social isolation have higher HF incidence in the Atherosclerosis Risk in Communities (ARIC) study; and (ii) to determine whether the association between social isolation and incident HF is mediated by vital exhaustion.
Abstract and Introduction
Abstract
Aims Prospective studies have shown that social isolation (i.e. lack of social contacts) predicts incident coronary heart disease (CHD), but it is unclear whether it predicts incident heart failure (HF) and what factors might mediate this association. HF patients may be more susceptible to social isolation as they tend to be older and may have disrupted social relationships due to life course factors (e.g. retirement or bereavement). We prospectively examined whether individuals with higher vs. low social isolation have a higher incidence of HF and determined whether this association is mediated by vital exhaustion.
Methods and results We estimated incident HF hospitalization or death among 14 348 participants from Visit 2 (1990–1992) in the Atherosclerosis Risk in Communities (ARIC) study using Cox proportional hazard models which were sequentially adjusted for age, race/study community, gender, current smoking, alcohol use, and co-morbidities. We conducted mediation analyses according to the Baron and Kenny method. After a median follow-up of 16.9 person-years, 1727 (13.0%) incident HF events occurred. The adjusted hazard of incident HF was greater for those in the higher vs. low social isolation risk group (hazard ratio 1.21, 95% confidence interval 1.08–1.35). Our data suggest that vital exhaustion strongly mediates the association between higher social isolation and incident HF (the percentage change in beta coefficient for higher vs. low social isolation groups after adjusting for vital exhaustion was 36%).
Conclusion These data suggest that greater social isolation is an independent risk factor for incident HF, and this association appears to be strongly mediated by vital exhaustion.
Introduction
Heart failure (HF) is a complex disease which represents the final common pathway for many diseases of the heart. HF affects ~6 million Americans, with US$37 billion in direct costs. It is a major cause of morbidity and mortality and thus is considered by policymakers as a high priority condition. As the population ages and therapeutic advances result in greater survival after acute cardiac events, the incidence of HF will continue to rise.
Social relationships affect the aetiology and prognosis of cardiovascular diseases (CVDs), and extant research often operationalizes social relationships through the concepts of social support and integration. Social support refers to the quantity and quality of resources (e.g. emotional, tangible, and informational) available through social interactions with others. Social integration reflects the number and types of social ties to others (e.g. marital status, amount of family and friend contact, and group membership). Although related, social support and integration are distinct concepts with only moderate correlations. Social integration is thought to protect or enhance health by providing a source of generalized positive affect which reduces psychological distress, enhances one's motivation for self-care, suppresses neuroendocrine responses, and enhances immune function. Conversely, lack of social integration (i.e. social isolation) is considered a 'stressor', inducing a negative psychological state which can increase neuroendocrine responses, suppress immune function, and interfere with performance of health-promoting behaviours. Over time, social isolation may lead to vital exhaustion, which is defined by excessive fatigue, feelings of demoralization, and increased irritability, and is considered an adaptation to prolonged psychological distress. Vital exhaustion is conceptually related to depression, and some studies report a correlation coefficient as high as 0.76 between measures of vital exhaustion and depression. However, guilt and low self-esteem—key features of depression—are largely absent among exhausted persons. Previous studies show a positive association between vital exhaustion and incident cardiac events.
Social support and social networks have also been shown to predict incident coronary heart disease (CHD) in five of eight long-term prospective studies reviewed. Although important, CHD causes only about half of the cases of incident HF in the general population under age 75, so it is worthwhile also to examine whether social relationships predict incident HF. However, few studies have specifically examined the association between social isolation and incident HF even though HF patients tend to be older and may have disrupted social relationships due to life-course factors, such as retirement and bereavement. Further, little is known about the potential mediators of this association. Vital exhaustion is one potential mediator of the association between social isolation and incident HF. Therefore, the objectives of this study were to: (i) prospectively examine whether individuals at higher vs. low risk for social isolation have higher HF incidence in the Atherosclerosis Risk in Communities (ARIC) study; and (ii) to determine whether the association between social isolation and incident HF is mediated by vital exhaustion.
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