Durk Pearson & Sandy Shaw’s®
Life Extension NewsTM
Volume 15 No. 2 • March-April 2012


If you think education is expensive, try ignorance.
— Derek Bok
(D&S Comment: Good point, but all too much “education” seems to be ignorance in disguise. Caveat emptor.)

Negative and Competitive Social Interactions Are Predictive of Increased Proinflammatory Activity

Increased stresses in a society of diminishing economic potential (and, hence, uncertainty about future financial status) and a rapidly shrinking domain of personal freedom has effects on health and behavior. A new paper1 reports on the increased release of proinflammatory cytokines IL-6 and TNF-alpha (tumor necrosis factor-alpha) in participants in relation to their exposure to social threat. The participants were recruited at a large university via ads offering $120 for taking part in the study. The final sample consisted of 122 students and employees (63 men and 69 women, with 38.5% being European American and 61.5% being Asian American.

The participants first kept daily diaries for 8 days that recorded positive, negative, and competitive social interactions. This was followed by laboratory stress challenges (the Trier Social Stress Test) and the measurements at baseline and at 25 and 80 minute poststressor from oral mucosal fluids of IL-6 and soluble receptor for tumor necrosis factor-alpha (sTNFalphaRII).

As the researchers explain in their introduction, “increases in proinflammatory cytokines IL-6 and TNF-alpha have been linked to hypertension, atherosclerosis, coronary heart disease, depression, diabetes, and some cancers.”1 Moreover, they report that “[p]eople who are socially integrated or have larger social networks have been found to have lower IL-6 and C-reactive protein (CRP), a byproduct of IL-6 activity.” “Chronic relationship stress characterized by conflict, mistrust, and instability, although not consistently related to basal levels of pro­inflammatory cytokines, have been tied to greater lipopolysaccharide-stimulated IL-6 production 6 mo. later.” Lipopolysaccharide is a bacterial product that activates the immune system. The researchers wanted to investigate the implications for inflammation of everyday social encounters, including competitive interactions, in natural (not laboratory) settings. They focused on three types of competition: competitive leisure time activities such as sports, academic or work-related competition, and competition for another person’s attention, such as romantic partners or friends.

The three categories of competition were evaluated for their prediction of relation to baseline proinflammatory cytokine levels and reactivity during acute stress (the lab tests). Leisure time competition did not predict any of the cytokine measures. Academic/work-related competitive encounters predicted baseline IL-6 (marginally significant) and sTNFalphaRII, while competing for another person’s attention significantly predicted baseline levels of IL-6. (The analysis was based on 522 competitive interactions; the researchers suggested that further research on subtypes of competitive events on inflammatory activity is needed. Presumably, this is a hint that they would be delighted if they were provided with grants to perform the necessary research!)

Negative social interactions were also found to significantly predict higher baselines of sTNFalphaRII, sTNFalphaRII and IL-6 responses following a social stressor, and total output of sTNFalphaRII.

The authors suggest that “[p]hysiologically, stress hormones may mediate the link between daily social interactions and inflammation. Social stressors, including negative social interactions, lead to increased cortisol, and cortisol tends to have a suppressive effect on inflammatory processes ... However, repeated exposure to social stress and cortisol may lead to resistance to the anti-inflammatory effects of glucocorticoids.”

Curiously, in this study the results did not support the hypothesis that positive daily social interactions would be tied to lower proinflammatory cytokine levels and reactivity to stress, as the researchers had supposed. A possible explanation, they suggest, is that some positive social interactions occurred as efforts at social support when participants were experiencing stress.

As the researchers note, these results are correlational and, hence, cannot provide definitive conclusions on causality. However, there is a substantial body of evidence supporting negative effects of chronic inflammatory activity on health and cognition.

Reference

  1. Chiang et al. Negative and competitive social interactions are related to heightened proinflammatory cytokine activity. Proc Natl Acad Sci USA 109(6):1878-82 (2012).

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