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Social relationships have long-term implications for health (1). In community samples, social isolation compared with known risk factors (smoking, obesity, and hypertension) in predicting increased morbidity and mortality (2). Similarly, in clinical samples, dependable nonhousehold social relationships predicted the survival of breast cancer patients at 9-year followup (3), and marital quality predicted 8-year survival among heart failure patients (4).
Social relationships, like other forms of social support, exert health-beneficial effects through biologic and behavioral pathways by influencing behaviors, cognitions, and affect (5). For example, social relationships may influence individuals to exercise, diet, and maintain medication regimens (behavioral pathways). Concomitantly, supportive relationships may influence cognitions and provide affective experiences that help regulate neuroendocrine, immune, and cardiovascular function (biologic pathways) (5–7).
Social relationships may have greater impact through biologic pathways for persons with rheumatoid arthritis (RA), a systemic inflammatory autoimmune disorder, due to their implications for the stress- and emotion-activated neuroendocrines relevant to RA disease activity. Zautra and colleagues (8) found that patients with RA are more psychologically and physiologically reactive to interpersonal stressors. Specifically, associations among interpersonal conflicts, depression, and the immune-stimulating hormones prolactin and estradiol were larger for patients with RA than for controls with osteoarthritis (8). Additionally, increased interpersonal stress resulted in increases from baseline in immunologic and clinical disease activity for women with RA (9). Similarly, chronic interpersonal stressors were linked with cellular inflammation, measured as in vitro production of the inflammatory cytokine interleukin-6 by the immune cells of patients with RA, and with resistance of this cytokine production to glucocorticoid inhibition (10).
Aspects of close, long-term social relationships such as marital status and couple relationship quality have also been linked with RA outcomes, leading to an increased focus on couple factors in RA coping (11, 12). For example, single patients with RA developed disability more rapidly than did married/partnered patients with RA over a 10-year period (13). Beyond simple marital status, the quality of spouse relationships appears to be important in the health of patients with RA. Spouses' negative reactions to RA patients' pain predicted depression at baseline and pain at 1-year followup (14). Similarly, spouse criticism and negative responses predicted increased depression and anxiety (15) and poorer coping (16), as well as larger increases in disease activity and anxiety from baseline to the occurrence of an interpersonally stressful period (17). In light of foreseeable long-term daily exposures to partners, such findings suggest that the couple relationship quality of patients with RA warrants attention.
As demonstrated above, couple relationship quality has often been measured as a stressor or risk factor in RA. However, the development of psychosocial interventions to enhance the health of patients with RA would be facilitated by clear descriptions of positive relational behaviors known to enhance health that could usefully serve as therapeutic targets.
Mutuality, a positive relationship quality of connectedness, is marked by the reciprocal sharing of thoughts and feelings in close relationships. Theorized as important for women's psychological development and health, mutuality is characterized by engaged, authentic, empathic exchanges that empower and broaden both partners (18, 19). Mutuality shares the features of responsiveness and empathy with two similar constructs. One is the model of intimacy, in which benefits of being encouraged to disclose accrue primarily to the discloser, who feels understood and valued by an empathic listener (20). The other is emotional responsiveness, defined as addressing the communications, needs, wishes, and actions of one's partner (21), thereby increasing that partner's feeling of being understood and valued. However, the conceptualization of mutuality differs from intimacy and emotional responsiveness in its emphasis on equal empowerment of both partners by their shared understanding resulting from empathic exchanges (18).
Measured as the frequency of partners' engaged, authentic, empathic responses during important conversations (22), couple mutuality has been linked with psychological health for women. Consistently associated with fewer symptoms of depression (23–27), mutuality also predicts more self-care agency in women coping with cancer (26) and discriminates between eating-disordered women and healthy controls (27). In patients with RA, couple mutuality is linked in cross-sectional data with better outcomes, including fewer symptoms of depression and anxiety, less physical disability, and less overall arthritis impact (28).
It is not known whether mutuality merely correlates with RA health or has a beneficial (causal) role. No experimental manipulations of mutuality have been conducted to provide evidence addressing this question. Lacking such experimental data, the exploration of potentially causal relations can usefully begin with an examination of cross-lagged effects in observational prospective data (29). The underlying logic and goal of such an examination is to provide some evidence of temporal precedence, and hence causal predominance, of one variable relative to the other. In essence, where A exerts lagged effects on B, and where B does not exert lagged effects on A, we may entertain an initial hypothesis that A is causally prior to and exerts influence on B. The absence of differences in cross-lagged correlations has been proposed as evidence of spurious associations between two variables that are actually driven by unlabeled intervening variables (30). Although confidence in causal orderings ultimately requires evidence from experimental data, an examination of cross-lagged effects can be considered a first stage in developing arguments for causal orderings (29).
Regressions examining cross-lagged effects have been used in preliminary analyses, revealing that the baseline mutuality of patients with RA predicted better outcomes at 6 months, including less arthritis impact, less anxiety, less pain and fatigue, better overall health, and less physical disability, after controlling baseline outcome levels. These analyses were consistent in finding lagged effects of mutuality on health outcomes, suggesting a beneficial effect of mutuality in RA health (31–35). However, these preliminary analyses captured only one 6-month period of prospective data. Confirmation of such results in a second time span would increase confidence in the evidence of causal relations.
In this study, we tested potentially causal relations of couple mutuality and an RA-relevant health indicator, inflammation, using prospective observational data obtained by questionnaire and medical chart review from female patients with RA that included 2 time spans for cross-lagged analysis. Utilizing erythrocyte sedimentation rate (ESR) as our measure of inflammation, we hypothesized that mutuality exerts a beneficial effect that is causally prior to subsequent levels of inflammation. As a corollary, we hypothesized that ESR is not causally prior to mutuality. Therefore, we expected that mutuality would exert lagged inverse effects on ESR, and in contrast that ESR would not exert lagged effects on mutuality.
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- MATERIALS AND METHOD
- AUTHOR CONTRIBUTIONS
In this study, we found that couple mutuality exerted a beneficial effect on inflammation for female patients with RA over two 6-month time spans. Utilizing a cross-lagged model for our regression analyses, we determined that female patients with RA who reported more mutuality at baseline and 6 months had lower levels of ESR at 6 and 12 months, respectively. After controlling for lagged effects of earlier inflammation, DMARD regimens, antiinflammatory drugs, RA disease flares, and negative affect, mutuality's lagged inverse effects explained unique variance, accounting for 9% and 12.5% of ESR variance at 6 and 12 months, respectively. The only significant predictor of 12-month ESR was 6-month mutuality (β = −0.480, P = 0.020) (Table 3). Conversely, ESR at baseline and 6 months exerted no effects on subsequent measures of mutuality. These results support our hypothesis that mutuality is a beneficial factor, suggesting mutuality's clinical relevance for female patients with RA. Our findings are congruent with other studies in rheumatology populations that link physical and psychological benefits with couple relationship qualities (9, 14–17, 35), especially those conceptualized as mutuality or emotional responsiveness (28, 45).
It is worth noting that the observed effects of mutuality were not only statistically significant, but could also have clinical significance and potential applications. For women, normal ESR levels are not higher than half the sum of their age in years plus 10 (e.g., ESR ≤25 mm/hour for a 40-year-old woman) (46). A 1-point difference in the mutuality score, representing the difference between reporting that empathic, engaged responses occur most of the time versus all of the time, was associated with estimated differences in ESR levels of 10.7 mm/hour at 6 months and 7.15 mm/hour at 12 months. These estimates represent approximately two-thirds of an SD in ESR for each test. Therefore, modest differences in the mutuality score may denote clinically significant differences in the ESR levels of some patients with RA. Given foreseeable long-term daily exposures within couple relationships, the magnitude of these estimates suggests that asking patients with RA whether they can engage in mutual conversations with partners would have clinical prognostic value in routine care.
Insofar as mutuality and other forms of social support represent unique sources of variance in RA outcomes that reflect clinically significant differences, reliance on exclusively pharmacologic therapies may fall short of optimal care. The fact that many DMARD treatments for RA carry potentially serious side effects yet are not universally effective underscores the desirability of developing psychosocial interventions to promote the health-enhancing relational behaviors that arise naturally in interpersonal relationships. The current study provides initial evidence that the relational behaviors measured as mutuality (engaged, authentic, empathic, and validating responses) exert a beneficial effect relative to inflammation for female patients with RA, suggesting their potential usefulness as therapeutic targets.
In a discussion of social relationships and issues for measurement and intervention, Cohen et al described some successful and unsuccessful attempts to harness social support to benefit chronically ill patients. They concluded that interventions targeting supportive groups and dyads hold great potential, because these formats provide for more tight control over the matching of participants, key maneuvers, and type of support delivered (6). Of these relational formats, we note that couple dyads present a unique therapeutic opportunity in terms of long-term daily exposure to a potentially health-enhancing relationship. Those authors further stated that ultimately the greatest benefits were found for patients who formed new relationships characterized by mutual exchanges (6). Other authors have also concluded that the meanings of giving and receiving support for interpersonal relationships have important implications for the acceptability and value of such support (47, 48). Revenson and colleagues found that problematic support (i.e., support that was not requested or was not responsive to the needs of the recipient) was associated with depression and was itself a source of stress for patients with RA (49). Congruent with those findings, Fekete and colleagues found that spouses' emotional responsiveness mediated the effects of the support they provided on their partners' psychological well-being in a study of couples in which the wife was experiencing a lupus disease flare (45). Such emotional responsiveness is consistent with mutuality.
As conceptualized and measured in the current study, mutuality involves a bidirectional flow of thoughts and feelings in which both partners are empowered by their shared understanding and develop psychologically through engaged, authentic, empathic exchanges (18). For the purposes of designing an intervention to enhance couple mutuality, the notion of mutual benefit to partners is consistent with the observation noted above that the most health benefit was found for patients who experienced mutual exchanges with their helpers (6). These considerations suggest that developing an intervention to enhance couple mutuality could promote sustained health benefits for patients with RA.
Important strengths of the study include its prospective design and the replication of directional results over two time spans. Further, our results are congruent with other studies. In addition, the linkage of a self-report measure of relationship quality with an objective medical measure of inflammation argues persuasively for the importance of psychosocial factors for physical health.
Some important limitations inherent in our nonexperimental design warrant caution in the interpretation and generality of the findings. In the absence of experimental data, an examination of cross-lagged effects provides a useful starting point for causal hypotheses (29). However, confidence in causal orderings should ultimately be based on evidence from an experimental design, such as testing the effect of mutuality enhancement on outcomes. Concomitantly, our nonexperimental design cannot exclude the possibility that observed effects of mutuality on health were due to intervening variables that we did not measure and control, such as individual differences (personality traits, disease severity, etc.) that might influence both mutuality and inflammation. We attempted to account for this type of intervening variable by controlling for negative affect, RA disease flares, and medications as approximations of relevant individual differences (44). We also tested the reverse-causality hypothesis to help rule out other potential intervening variables (Table 4) (30). Another limitation is that only 1 outcome, ESR, was used here to test our hypothesis; confidence in our finding would be increased by replicating this finding in other outcomes, such as physical disability, pain, and fatigue. Additionally, most of our sample of female patients with RA identified themselves as well-educated and white, limiting the generality of our findings to less-educated and more ethnically diverse populations. Finally, the average 23-year couple relationship duration and average 5-year RA disease duration may reflect couple stability and patient experience in coping with RA, forming a context in which couple relationship quality could emerge as a beneficial factor for RA health. It is quite conceivable that we would have found the opposite result in a sample of newly coupled patients with RA dealing with the initial impact of an RA diagnosis, i.e., that disease is a risk factor for couple relationship quality.
In conclusion, our findings join an accumulating body of evidence linking social relationships with health. The current findings suggest that mutuality exerts prospective beneficial effects on inflammation in women with RA. Given the effect sizes and foreseeable ongoing daily contact with partners, couple mutuality could have long-term clinical significance for some patients. Further elucidation of mutuality's role in RA health could inform new interventions targeting health-enhancing relational behaviors to improve outcomes and quality of life for individuals living with arthritis.