Interpersonal stressors predicting inflammation in adolescents: Moderation by emotion regulation and heart rate variability?

This study assessed interpersonal stressors (peer adversity and parental rejection) as predictors of adolescents' circulating inflammatory markers, while examining emotion regulation and parasympathetic nervous system activity (at rest, reactivity, and recovery) as potential protective moderators. Data were collected in a Belgian cohort of adolescents in 2017 (n=185, 51.4 % boys, 10-18 y) and 2018 (n=98), and included serum inflammatory markers (CRP, TNFα, IFNγ, IL-6, IL-8 and IL-10), peer adversity, parental rejection, emotion regulation and heart rate variability (RMSSD-HRV, at rest and in 2018 also in response to a Trier Social Stress Test). Contrary to the hypothesis, interpersonal stressors were negatively related to TNFα (in 2017 and 2018), IFNγ (in 2017 and longitudinally) and IL-6 (in 2018). In 23 % of the tested associations, HRV at rest was a significant moderator: the negative stressor-inflammation associations were present only among adolescents with low HRV resting values. No significant moderation by HRV reactivity or recovery was detected. After correction for multiple testing, all above-mentioned significant findings disappeared. These unexpected findings may suggest that the positive association between stress exposure and circulating markers of inflammation is not yet detectable in adolescence and perhaps becomes evident only later in life.