The quality of one’s social relationships is reliably related to physical health outcomes ^[1][2][3][1,2,3]. 

Much of the prior work has focused on the biological mechanisms underlying the link between social support and health ^[4][7]. Of these biological mechanisms, inflammation has emerged as one of the more compelling pathways, considering its mechanistic links to cardiovascular disease morbidity and mortality ^[5][6][7][8,9,10]. A recent meta-analysis reported a small effect size linking social support to inflammatory cytokines ^[8][11]. Given the links between social support and broad-based mortality ^[9][4][4,7], an inflammatory pathway might explain part of its ties to health.

An important limitation in the literature is that all studies to date appear to examine if a person’s level of social support predicts their own inflammatory outcomes ^[10][11][12][12,13,14]. This intra-individual perspective highlights models in which social support processes perceived by the individual might influence their health and assumes that these perceptions, in part, reflect past support exchanges. However, research on invisible support and early life determinants of perceived support makes it clear that there are interpersonal determinants of support that have implications for its conceptualization ^[13][14][15,16]. Such interpersonal determinants of social support can be tested using actor–partner models, highlighting the interdependence between individuals within relationships ^[15][17]. 

There is strong evidence that close social network members influence inflammation ^[16][18]. In a study by Donoho and colleagues, 2013, marital quality was seen as an important predictor of inflammation on the inflammatory biomarkers of C-reactive protein and interleukin-6 ^[17][19]. However, only limited work has examined dyadic influences on biomarkers to date, revealing links with cortisol, cardiovascular reactivity, and inflammation. Coregulation of actor–partner cortisol levels has been shown between couples and their mood states, with marital satisfaction acting as a possible buffer to the partner’s negative mood or stress state ^[18][19][20,21]. Furthermore, dyadic effects on cardiovascular reactivity measures have been observed ^{[20][21][22][23][24][25]}[22,23,24,25,26,27], including partner influences of trait hostility and anger ^[26][28]. A review examining the immune system, marriage, and divorce also found that partners influence each other’s mood and health behaviors, producing both direct and indirect downstream effects on the immune system ^[27][29]. This evidence suggests that one’s perceived social support may influence inflammatory biomarkers in their partner. When conceptualized as a dyadic or interpersonal process, there are several specific reasons to expect partner influences of perceived support on health. For example, being married to a person high in perceived support might simply be less stressful compared to being married to someone low in support ^[16][28][18,30]. Given that the partner has adequate support, they would have the resources needed to attend to their partner’s socio-emotional needs ^[29][30][31,32]. Additionally, perceived support is related to received support. Therefore, if a partner has higher levels of perceived support, this may be reflective of more responsive reciprocity in support processes ^[31][33]. Due to the reciprocal nature of dyadic relationships, one’s perception of support can ultimately affect partner responsiveness and self-disclosure and act as a buffer against stress or negative moods ^[18][19][22][20,21,24]. These processes (e.g., support reciprocity) between an actor and their partner may cushion the effects of stressors and consequent health issues ^[32][33][34,35].

2. Research Findings

The main results indicate that a partner’s level of perceived support was related to lower inflammation in their spouse. These results remained unchanged while statistically controlling for a number of demographic variables, including medication use and one’s own level of perceived support. These data highlight the importance of taking a dyadic perspective on perceived support, given the interdependence of individuals within relationships. It was predicted that both actor and partner levels of perceived support would be related to lower levels of inflammation. Only partner levels of perceived support were associated with lower inflammation. There are a number of plausible reasons for the existence of such an association, and it requires future research. Given that marital relationships are among the most important in adulthood, a spouse with higher perceptions of support might be associated with smoother interpersonal interactions in daily life and over time. Importantly, such processes might not be captured by actor measures of support, which only reflect an individual’s own perception of support and their own interpersonal functioning. For instance, prior work indicated that social support is related to better social skills ^[34][46]. It is thus possible that partners high in perceived support may engage in more effective and responsive support, such that actors benefit from its positive influence ^[13][35][15,47].  It is also possible that this study captures the interpersonal and intrapersonal synchrony of perceived support within a relationship. At least one study has linked interpersonal mechanisms and close relationships to health ^[36][48] through the coregulation of emotion, cognition, behavior, and physiology within the dyad. This coregulation or psychophysiological homeostasis between partners has been seen to affect physical and emotional health ^[37][49]. Nonetheless, the interplay between intrapersonal and interpersonal perceptions within the dyad would need to be addressed in future research. Although the directionality of effects cannot be investigated within cross-sectional data, there is some evidence suggesting a coregulation of inflammation and social behavior that could be an interesting avenue for future work. Two reviews on inflammation and social processes found that inflammatory processes regulated social behavior, inasmuch that neural sensitivity to positive and negative social feedback was seen to be enhanced ^[38][39][50,51]. Therefore, inflammation levels may have contributed to social behaviors that elicited support from partners. That is, when the need for support is recognized and perceived by the partner, it has the potential to influence actor levels of inflammation. Although this is speculative and requires future work, it is consistent with the growing literature documenting the bi-directional links between inflammation and social processes. Significant relationships were found between actor–partner perceived social support, inflammation, and BMI, and between actor–partner perceived social support, inflammation, and gender. Research shows that there is a substantially increased risk of obesity when one’s partner is obese. It is thought that relationships can normalize the idea of obesity, making it more acceptable to become obese ^[40][52]. Additionally, studies have shown that increased obesity can then lead to an increase in inflammation ^[41][42][53,54]. In sum, the normalization of a higher BMI through one’s partner increases the likelihood of an increased actor BMI and the associated inflammation seen with increased adipose tissue. Regarding the relationship seen with gender, inflammation was seen to be lower in women than in men. This is thought to be due to the general anti-inflammatory properties associated with estrogen ^[43][44][55,56].

3. Conclusions

Contrary to the predictions, actor levels of perceived support did not predict lower levels of inflammation. However, in the expected direction, the association was not significant. Based on a recent meta-analysis, the effect size linking social support to inflammation is small, at r = −0.07 ^[8][11]. Hence, it is likely that the current study was underpowered to detect such an association at a conventional level of significance. The nonsignificant finding for actor support also highlights the relatively larger effect sizes for partner levels of support. If similar results are confirmed in future studies, they may underscore the importance of dyadic approaches to psychosocial risk, even for psychosocial risk factors that have traditionally been conceptualized as intrapersonal in nature.