A tale of two marital stressors: Comparing proinflammatory responses to partner distress and marital conflict.

Marital quality shares ties to inflammatory conditions like cardiovascular disease and diabetes. For decades, research has focused on marital conflict as a primary mechanism given its potential to trigger inflammatory responses. However, longitudinal evidence suggests that marital conflict declines over time, and little attention has been paid to the inflammatory aftermath of other types of marital exchanges. A spouse's emotional distress is an important but overlooked marital context, as partners are exposed to each other's upsetting emotions throughout adulthood. To directly compare reactivity in proinflammatory gene expression to these two marital stressors and to examine differences by age and marital satisfaction, 203 community adults ages 25-90 (N = 102 couples) provided blood samples and rated their negative mood before and after they 1) watched their partner relive an upsetting personal memory and, in a separate visit 1-2 weeks later, 2) discussed a conflictual topic in their relationship. Controlling for age, sex, race/ethnicity, BMI, alcohol use, smoking, and comorbidities, increases in proinflammatory gene expression were significantly larger after the partner's upsetting disclosure than after marital conflict (B = 0.073, SE = 0.031, p = .018). This pattern paralleled emotional reactivity to the tasks, wherein negative mood rose more in response to the partner's disclosure than to marital conflict (B = 4.305, SE = 1.468, p = .004). In sum, proinflammatory and mood reactivity to spousal distress exceeded reactivity to marital conflict, a well-established marital stressor. Findings reveal spousal distress as a novel mechanism that may link marriage to inflammation-related diseases, and even pose risks for both happy and unhappy couples across adulthood.

Depression, Inflammation, and the Moderating Role of Metformin: Results from the Midlife in the United States (MIDUS) Study and Sacramento Area Latino Study on Aging (SALSA).

OBJECTIVE: Depression can promote inflammation and accelerate aging. Metformin, a widely prescribed antidiabetic, has shown promising preclinical evidence of aging-related health benefits, including decreased inflammation. The current study examined whether metformin usage buffers the association between depressive symptoms and inflammatory markers in two large samples of middle-aged and older, primarily white adults, and older Latino adults. METHODS: Data from the Midlife in the United States Study (MIDUS; N = 1255) and the Sacramento Area Latino Study on Aging (SALSA; N = 1786) included information on medication use, depressive symptoms, and inflammatory markers, namely IL-6, TNF-α, and CRP. These data were merged into a harmonized sample, and the sample group variable was included in a three-way interaction for analysis. RESULTS: Specifically, in the MIDUS sample, metformin buffered the association between depressive symptoms and CRP (b = -0.029, SE = 0.013, p = .007) and IL-6 (b = 0.21, SE = 0.010, p = .046), while no significant association was found with TNF-α. Metformin non-users displayed higher depressive symptoms associated with elevated CRP (b = 0.01, SE = 0.003, p < .001) and IL-6 (b = 0.011, SE = 0.003, p < .001), whereas this association was not present among metformin users (ps > .068). Conversely, in the SALSA sample, metformin use did not show a significant protective link. CONCLUSION: Results from mostly white, highly educated adults supported a mitigating role of metformin in ties between depression, a well-known behavioral risk factor, and inflammation, a key source of biological aging. However, the benefits did not extend to a large sample of older Mexican Americans. The findings reveal a hidden potential benefit of this therapeutic agent and raise important questions around its health equity.Trial Registration: The study was pre-registered on OSF (https://osf.io/c92vw/).