Abstract
Objectives
Age-associated accelerated declines in physical health vary across individuals, and researchers have suggested that individual differences in decline may vary as a function of stressors. The relation of one such stressor, negative social exchanges, to accelerated declines in self-rated health is investigated.
Method
Participants are from a 2-year, 5-wave, national, longitudinal study of social relationships among older adults. Growth curve analyses are used to examine the relation of negative and positive social exchanges to accelerated changes in self-rated health, controlling for age, sex, race/ethnicity, education, and depressive symptoms.
Results:
Individuals reporting more frequent negative social exchanges showed significantly accelerated declines in physical health. Positive social exchanges were not related to linear or accelerated declines in self-rated health over time.
Discussion:
The association between negative social exchanges and accelerated deterioration in self-rated health provides general support for hypotheses that interpersonal stressors play an important role age-related physical health decline.
Aging of the human body is evident in the increasing risk of morbidity and mortality in older life. Although, on average, the probability of disease or death increases with advanced age (Arias, 2002), the rate of decline in physical health varies considerably across individuals (Fries, 1980; Strehler & Mildvan, 1960; Svedberg et al., 2005). Even at older ages, physical health may remain constant or improve for some individuals (Holt-Lunstad et al., 2017; Vogelsang, 2018). Factors such as genetic differences (Shadyab & LaCroix, 2015) are likely to explain variation in physical health trajectories across individuals, but individual differences in the accumulation of stress, or allostatic load, also may explain why physical health declines more quickly in some individuals than in others (Beckie, 2012; McEwen & Stellar, 1993). Exposure to stressors, particularly over prolonged periods, is known to be important in the development of serious physical health conditions, such as hypertension and heart disease (Kivimäki & Steptoe, 2018). Stress most likely leads to disease by encumbering neuroendocrine, immune, and cardiovascular system functioning (Kiecolt-Glaser et al., 2010), which compromises the ability of people to cope with stress in late life (Spence, 1995). Accordingly, individual differences in rates of decline in physical health associated with aging may be at least partially a function of exposure to different levels of stress.
With increasing age, the risk of failure of one or more of the body’s physiological subsystems increases. The combined risk of multiple subsystems results in accelerated increases in morbidity or mortality that are observed in life expectancy studies (Arias, 2002; Gavrilov & Gavrilova, 2015a; Strehler & Mildvan, 1960). Thus, a process in which stress impacts neuroendocrine, immune, and cardiovascular system functioning implies an exponential decline in overall physical health associated with aging. Although an accelerated decline in physical health in late life is observed on average, Fries (1980) emphasized that the modifiability of this trajectory accounts for the dramatic individual differences in physical health changes that accompany advancing age, and suggested that “social interaction, promotion of health, and personal autonomy may postpone many of the phenomena usually associated with aging” (p. 135).
Social Exchanges and Physical Health
Humans, like all primates, have strong needs for well-functioning social relationships (Baumeister & Leary, 1995; Ellis et al., 2019). These social needs have an important place in hierarchical structure of human motivations necessary for survival (Kenrick et al., 2010), explaining why social relationships have an integral function in later life (Antonucci et al., 2014). Indeed, a wealth of research has documented that social exchanges are an important factor accounting for individual differences in physical health (Hawkley & Capitanio, 2015; Holt-Lundstad et al., 2017; Kiecolt-Glaser & Wilson, 2017; Newsom et al., 2008; Pietromonaco & Collins, 2017; Rook et al., 2011). We define social exchanges as interpersonal contacts with family, friends, or others in one’s social network that can be of a favorable, affirming nature, or an unfavorable, upsetting nature.
Positive social exchanges primarily consist of what is commonly referred to as social support but can also include other positive interactions, such as companionship. Positive social exchanges have long been believed to play a preventive role in physical health (Cassel, 1976), and studies have borne out their connection to lower risk of chronic health conditions, functional limitations, and mortality (de Brito et al., 2017; Holt-Lunstad et al., 2017; Rook et al., 2012; Shor et al., 2013).
Social exchanges are not always beneficial to physical health, however, as they can also be a significant source of stress in daily life (Beckie, 2012; McEwen & Stellar, 1993; Wheaton et al., 2013). Negative social exchanges, which include aversive behaviors by social network members such as criticisms, intrusiveness, and insensitivities, can be chronic in nature (Krause & Rook, 2003), leading to important cumulative impacts on health (McEwen, 2017). The association between negative social exchanges and poorer physical health has been documented across a variety of different physical health indicators, including more arthritis symptoms (Pow et al., 2018), greater risk of cardiovascular disease (Orth-Gomer et al., 2000), poorer physical functioning (Hakulinen et al., 2016; Krause & Shaw, 2002; Mavandadi et al., 2007), lower self-reported health (Heymann et al., 2016; Krause, 1996; Newsom et al., 2008), and impaired immune response (Kiecolt-Glaser & Wilson, 2017). Although many studies documenting this association have been cross-sectional, leaving ambiguity about the causal direction of the relationship, prospective studies have lent support to the notion that negative social exchanges may lead to poorer physical health (Hakulinen et al., 2016; Newsom et al., 2008).
Positive and negative social exchanges may not have equivalent impacts on physical health, however. Findings indicate greater overall impact of negative social exchanges on mental health and physical health as compared to the effects of positive social exchanges (for a review, see Rook, 2015). The differences in impacts of positive and negative social exchanges may be rooted in the centrality of social relationships for survival, in which the adaptive benefit of avoiding threatening individuals outweighs the adaptive benefit of seeking supportive individuals (Haidt, 2006; Kemeny, 2009). Negative social exchanges tend to be stable over time (Newsom et al., 2008), constituting a chronic source of stress, and tend to involve closer network members (Sorkin & Rook, 2004). Given the greater overall impact of negative social exchanges, individuals who experience more negative social exchanges should show a more rapid decline in physical health, that would account for some of the well-known individual variation in physical health declines associated with aging (Gavrilov & Gavrilova, 2015a) that are predicted by major theoretical perspectives of biological aging, such as damage or error theories (Jin, 2010). Understanding the relative impacts of negative and positive social exchanges on declines in physical health has potential implications for interventions and public health initiatives. If impact of negative social exchanges outweighs the impact of positive social exchanges, efforts could be better tailored to be more effective.
Self-Reported Health
One reflection of declining physical health can be found in changes in an individual’s own assessments of their general state of physical health. Self-ratings of health provide a useful global assessment of one’s overall, current physical health status (Benyamini, 2011; Latham & Peek, 2013). These simple but direct assessments of physical health have gained increasing credence as an important gauge of overall physical health status because studies have repeatedly demonstrated an association with mortality that is independent of other physical health measures and psychosocial predictors (Gupta et al., 2020; Idler & Cartwright, 2018; Latham & Peek, 2013; Osoba, 1999; Szybalska et al., 2018). Self-rated health is an indicator of overall physical health that may take many aspects of physical health into account, including the presence of disease (Falconer & Quesnel-Vallée, 2017), functional abilities (Latham & Peek, 2013; Takahashi et al., 2020), subclinical symptoms, and mental health. Self-rated health also exhibits exponential declines in physical health that occur with advancing age that would be expected to result from the failure of individual physiological subsystems (Bunda & Busseri, 2019; Ellaway et al., 2012). Self-rated health, therefore, is a measure that is well-suited for examining role of social exchanges in accounting for individual differences in physical health decline over time. Two studies have found that declines in self-rated health vary as a function of marital strain (Miller et al., 2013; Umberson et al., 2006). Results from these studies may not generalize to all individuals because they were limited to married individuals. Additionally, both studies modeled change over time linearly, which may be limiting if physical health in fact declines exponentially, rather than steadily over time.
Purpose of the Current Study
To date, studies that have compared the relative effects of positive and negative social exchanges on physical health have usually been cross-sectional. Cross-sectional studies are unable to demonstrate whether physical health declines over time are precipitated by social exchanges that would be expected through the supportive functions of social exchanges and deteriorating functions of negative social exchanges. The current study examines whether social exchanges explain variation in exponential declines in self-rated health associated with aging and whether positive or negative social exchanges may account for greater variability in this decline. We hypothesize that those with more frequent negative exchanges with network members will later exhibit more rapid declines in self-rated health than those with less frequent negative social exchanges. Further, we hypothesized that negative social exchanges would have a stronger relationship to declines in self-rate health than positive social exchanges. Physical health declines are expected to accelerate at an exponential rate because the increasing burden on physiological subsystems that is caused by the accumulation of greater interpersonal stress and will be manifested in accelerated risk of poor physical health. Moreover, because the impact of negative social exchanges on psychological distress has been found to outweigh the impact of positive social exchanges in cross-sectional studies, we hypothesize that negative social exchanges will have a greater effect than positive social exchanges in predicting declines in self-rated health over time as well. These hypotheses are investigated in a longitudinal study of a nationally representative sample of older adults that makes use of extensive and comparable measures of positive and negative social exchanges.
Method
Sample Recruitment and Participant Characteristics
The Late Life Study of Social Exchanges (LLSSE) is a national study of the physical and psychological health consequences positive and negative social exchanges. Participants were 916 community-dwelling older adults, ages 65–90. Only individuals who were English-speaking, cognitively functional, and living in the contiguous United States were eligible to participate. Survey responses were obtained over 2 years from the years 2000 to 2002, with interviews spaced 6 months apart (five waves). The first, third, and fifth waves were face-to-face interviews, whereas the second and fourth waves were telephone interviews. The sample was recruited from a 5% random sample of the Medicare Beneficiary Eligibility List, provided by the Centers for Medicare and Medicaid Services (CMS). CMS restricts access to the entire eligibility list, which contains tens of millions of adults. Thus, the random subsample process was used to help protect privacy and ensure that the study sample could be as representative of all Medicare-eligible older adults as practical. CMS, however, does not release information for beneficiaries who are 100 years of age and older or are non-legal residents. An initial contact was made by letter, followed by a phone call, resulting in a response rate of 53% of those who met eligibility criteria, who could be contacted, and who agreed to participate. All participants provided informed consent prior to participation in the study. This research was approved by the Portland State University (04254) and the University of California, Irvine (96-257) Institutional Review Boards.
Participants in the LLSSE were 74.16 years old on average (SD = 6.63), 62% were women, and 63% had a high school degree or less education. Eighty-three percent were White, 11% were African American, 5% were Latino, and approximately 1% were of other ethnicities (e.g., Asian, Native American). As a general check on the representativeness of the sample, an examination of U.S. Census data (U.S. Bureau of the Census: Current Population Survey, 2000) suggested the characteristics of the sample at wave 1 closely mirrored the characteristics of the older adult population at that time.
Sixty-seven percent (N = 666) completed the final wave of the study, and the primary reasons for attrition included death, physical health, change of residence, and refusal. Because of missing data on predictors in the growth curve analyses (including 30 participants who reported no positive or negative exchanges at wave 1), the final sample size used in all analyses was 608. Growth curve analysis does not require complete data on the dependent variable (self-rated health) at all waves, using expectation maximization estimation to obtain estimates where data are missing. We examined the extent to which missing data on the dependent variable was associated on model-related variables to gauge the extent to which analyses might be substantially biased by non-ignorable missing data. There were several significant differences in baseline characteristics between those who completed the final wave and those who did not, including lower self-reported health, greater difficulties in functioning, and lower education. Though significant, these differences were not large (r = −.07, r =. 08, and r = .07, respectively) and were not expected to lead to substantial biases in the overall findings.
Procedure
The survey, lasting approximately 70 minutes for in-person interviews and 15–30 minutes for telephone interviews, covered a wide range of content, including questions about sociodemographic characteristics, social relationships, physical health, and psychological distress. A major survey research firm with experience conducting surveys with older adults, Harris Interactive, Inc., conducted all interviews.
Measures
The measure of positive social exchanges, designed to have comparable content validity and reliability, assessed four parallel domains of social exchanges: informational support, instrumental support, emotional support, and companionship. This measure included 12 items (3 per domain) assessed the frequency (ranging from 0 “never” to 4 “very often”) of positive social exchanges with a “spouse, family members, friends, neighbors, in-laws or others.” Participants were asked “In the past month, how often did the people you know…” about exchanges such as “do favors and other nice things for you” or “say things that were kind or considerate of you.” An average of the 12 items was used in the analyses, with higher scores indicating more frequent positive social exchanges. Cronbach’s alpha was .90 for the total positive exchanges measure.
Overview of Analyses
Our hypotheses about change in self-rated health over time and negative social exchanges were tested using growth curve modeling in HLM version 8.0 (Raudenbush et al., 2019). We first examined a growth model of linear and exponential change before testing whether changes in self-rated health were dependent on negative social exchanges and a set of time-invariant covariates. Exponential change was tested by transformation of the time scores using the following formula
Results
Descriptive Analyses
Correlations Among Variables at Wave 1 and Self-Rated Health at All Waves (N = 608).
Note. * p < .05, ** p < .01, *** p < .001. The following codes were used for binary variables: sex (0 = male, 1 = female) and minority status (0=white, 1=racial/ethnic minority).
Change in Self-Rated Health
We first examined overall change in self-rated health with an unconditional model that included linear and exponential terms but no covariates. In accordance with Singer and Willett’s (2003) recommendations, we tested the assumption of constant residual variance over time (i.e., the homoscedasticity assumption). The chi-square test of this assumption indicated a significantly better fitting model if the residuals were allowed to vary over time (χ2(2) = 6.12, p = .045), and, thus, all subsequent results are derived from models that relax this assumption. Results from the unconditional model show that, although neither linear nor exponential change in self-rated health were significant (b = −.07, SEb = .06, p = .232; b = −.11, SEb = .14, p = .422, respectively), both linear and exponential trajectories varied significantly across individuals (τ11 = .32, χ2(606) = 707.32, p = .003; τ22 = 1.26, χ2(606) = 701.89, p = .004, respectively). The next analyses examined whether social exchanges account for variability in linear or exponential changes in self-rated health over time.
Growth curve analyses examining the effects of negative social exchanges on exponential changes in self-rated health (N = 608).
Note. Time was coded 0, 1, 2, 3, and 4, and, thus, the intercept represents average self-rated health (SRH) at baseline. Linear SRH represents linear growth in self-rated health over time, using time coefficients 0, 1, 2, 3, and 4. Exponential SRH represents nonlinear growth using an exponential transformation of the linear time coefficients. All predictors, including covariates, were measured at baseline. The following codes were used for binary variables: sex (0 = male, 1 = female) and minority status (0=white, 1=racial/ethnic minority).
The significant interaction between negative social exchanges and exponential time indicates that self-rated health changes at different rates for individuals reporting more frequent or less frequent negative social exchanges. To explore the nature of this interaction, we used the resulting growth curve equation to plot simple slopes for exponential change when the value of negative social exchanges was equal to 0, the mean, and 1 SD above the mean. Although 1 SD below the mean is often conventionally used for the lowest value at which the simple slope is plotted (Aiken & West, 1991), we used 0 (i.e., negative exchanges experienced “not at all” over the past month), as our lower bound plot point, because using −1 SD below the mean would have resulted in a slightly negative value on the scale. As shown in Figure 1, these simple slopes suggest that individuals with the highest negative social exchanges experienced more rapid exponential declines in self-rated health. Simple slopes for changes in self-rated health at no negative exchanges, average frequency of negative exchanges, and negative exchanges 1 SD above the mean.
Discussion
This study goes beyond prior work by investigating whether social exchanges predict differing rates of decline in self-rated health over a 2-year period, and, furthermore, whether negative social exchanges might be a stronger predictor of self-rated health decline than positive exchanges. Negative, but not positive, social exchanges significantly predicted declining self-rated health. Moreover, the results indicated that those who reported more frequent negative social exchanges were significantly more likely to show an exponential decay in self-rated health over the course of the study, reflecting a more rapid rate of deteriorating physical health for these individuals.
The results of this study have important implications for the role of stress in the aging process and add to several studies that have shown a relation between interpersonal conflicts and changes in self-rated health (Newsom et al., 2008; Umberson et al., 2006; Wickrama et al., 1997). Exposure to stressors is expected to accelerate physical health decline in older age through a weakening of the immune system’s capacity to recover from stress (McEwen & Lasley, 2002). Results of this study identify interpersonal interactions as one important source of stress associated with an accelerated decline in physical health. The potency of negative social exchanges as a stressor is likely derived from its interference with a marked need for affiliation among humans and other primates (Baumeister & Leary, 1995). Experimental studies of social disruption among non-human primates, in fact, have illustrated that social stress is noxious enough to have appreciable effects on longevity (Lund et al., 2014). This study forges new ground, however, in documenting the association of negative social exchanges and accelerated changes in self-reported health in a nationally representative sample of older adults.
The negative social exchanges measured in our study may have their impacts on physical health through cumulative process that occurs when interpersonal stressors are chronic in nature (McEwen, 2017; Pearlin & Bierman, 2013; Wheaton et al., 2013). We did not examine cumulative or chronically occurring negative social exchanges in these analyses, and, therefore, the results may represent an underestimation of the association with physical health (Newsom et al., 2008). Our measurement of negative social exchanges was global in nature and was not able to distinguish between less serious negative social exchanges, such as minor criticisms and more serious negative social exchanges, such as abuse. Moreover, the point during the life course that negative socials exchanges occur also may matter. Some authors have speculated that early damage due to more extreme stressors may have an important impact on physical health decline in later life (Gavrilov & Gavrilova, 2015b). Future research may help uncover how early life interpersonal stressors may interact with those experienced in middle and later adulthood to affect the rate of deterioration in physical health in later life (Suglia et al., 2021).
One question raised by the study is why positive exchanges were not protective against declines in self-rated health. Evidence suggests that receiving social support can trigger feelings of low self-efficacy or indebtedness in recipients (Zee & Bolger, 2019). Support can also be mismatched with recipients’ needs, as is sometimes the case with unwanted or insensitive advice (J. Smith & Goodnow, 1999). Thus, even well-intentioned support can have unintended negative effects. Compared with instrumental support, companionship should have fewer negative effects, as it is usually sought for the purpose of mutual enjoyment and, therefore, is less likely to be unwanted. Companionship also occurs between equals, rather than a helper and help-receipt, and, as a result, is less likely to arouse feelings of low self-efficacy or indebtedness (Rook et al., 2011). Comparing the links between self-rated health and support versus companionship was beyond the scope of the current study, but it warrants investigation in future research.
Limitations
Although an accelerated decline in self-rated health occurred in some individuals, we did not observe an accelerated decline in self-rated health on average. The relatively short 2-year time frame of our study, compared with other studies that have traced self-rated health changes over the life span (Svedberg et al., 2005), may explain why we did not find an average change in self-rated health in the sample. The short time frame of the current study represents only a brief cross-section of a longer developmental process, and, therefore, the nonlinear decline in health observed in our study should be far less evident than the decline observed over longer periods in other studies. Over longer time spans and at older ages, one might expect to see a more dramatic decay pattern on average. The role of negative social exchanges, to the extent that they are persistent, would also be expected to be stronger if observations were taken over longer periods, because development of more serious, chronic conditions takes place gradually over many years (Kaplan et al., 1999). Presumably those exposed to chronic stressors will experience greater impairment of the body’s restorative systems, resulting in greater risk of developing disease.
Our measure of global health is identical to the measure used in numerous national health surveys and epidemiological research, such as the Health and Retirement Study (HRS; Heeringa & Conner, 1995) or the National Health and Aging Trends Study (NHATS; Kasper & Freedman, 2014). Despite its widespread use, the single-item rating of overall health has been viewed with some skepticism by some researchers because the factors that individuals take into account in making ratings and the processes by which they weight those factors are largely unknown (Bombak, 2013). Respondents appear to take into account health conditions, functioning levels, and subclinical symptoms, and, thus, self-ratings of health do not appear to reflect a consistent or specific facet of health (Kaplan et al., 1999; Krause & Jay, 1994; Schnittker, 2003). A single-item rating may be subject to response bias, such as the tendency for some individuals to rate their health more negatively because they experience greater negative affect (Bailis et al., 2003), although the inclusion of a depression measure in this study at least partially addresses this possibility. Evidence supporting the predictive value of global self-ratings of health is irrefutable, however. Idler and Benyamini (1997) concluded from a review of 27 studies, that self-rated health represents an “irreplaceable dimension of health status” and that “an individual’s health status cannot be assessed without it” (p. 34).
Although the association of negative social exchanges and exponential declines in health is consistent with proposed notions of stress and aging, our study was unable to directly confirm these processes because we did not obtain data on immunologic or neuroendocrine markers involved in the hypothesized underlying mediational process. Cumulative effects of recurring or chronic stress are expected to increase the risk of disease and health decline through several physiologic systems (McEwen, 2017). Additional research that tests this proposed process and links it to older adults’ social exchanges will be valuable in advancing understanding of how some kinds of social ties and interactions may be implicated in declining health in later life.
Conclusion
The findings from our study provide further insight into two broad observations that frequently appear in the literature. The first observation is that changes in health in later life are nonlinear and that considerable variability in trajectories of health occurs with age (Gavrilov & Gavrilova, 2003; Nelson & Dannifer, 1992; Strehler & Mildvan, 1960). Evidence for this variability has generally been based on simple measures of dispersion taken cross-sectionally across cohorts. We add evidence by bringing more sophisticated individual growth curve analyses to bear on the issue, however. Our data suggest, as well, that there is significant individual variation in these nonlinear patterns of change in health over time.
The second broad observation in the literature that our study addresses concerns the differential effects of positive and negative social exchanges on health. The effects of negative social exchanges on well-being tend to be greater than the corresponding effects of positive social exchanges (Rook, 2015). This finding is consistent with views in the literature that “… bad is stronger than good. Responses to threats and unpleasantness are faster, stronger, and harder to inhibit than responses to opportunities and pleasures” (Haidt, 2006, p. 29; see also; Baumeister et al., 2001). Such “negativity bias” is not a new concept (A. Smith, 1759/2002), but is a well-documented phenomenon (Tierney & Baumeister, 2021). Given that the adverse health impact of negative social exchanges appears to outweigh the ameliorative impact of positive exchanges, these results have implications for interventions and policy. Specifically, the results suggest that greater focus is needed on reducing the impacts of harmful social interactions, in contrast to a more widely assumed focus of bolstering supportive interactions (Sitges-Maciá et al., 2021).
Footnotes
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was supported by National Institute on Aging Grants R01 AG022957 (Newsom), R01 AG14130 (Rook), and R01 AG009221 (Krause).
