Relationship between social support and autonomic function during a stress protocol in ulcerative colitis patients in remission

Background: The relationship of psychological stress to relapse in ulcerative colitis (UC) is inconsistent. This may be due to a failure to identify patient characteristics, such as social support, which moderate the transduction of stress from the central nervous system to the immune system. In this study we tested the hypothesis that social support enhances parasympathetic modulation of heart rate in UC. Methods: An indirect measure of autonomic function (heart rate variability; HRV) was measured in 108 patients with UC in remission during a standard protocol involving periods of stress, paced breathing, and relaxation. Social support was measured with the Social Support Questionnaire. Results: After controlling for age, which is strongly related to HRV, both satisfaction with social support (F = 5.7, significance = 0.002) and its interaction with age (F = 7.8, significance < 0.001) were associated with high-frequency HRV, which measures parasympathetic modulation of heart rate. Social support was associated with higher levels of high- frequency HRV at almost all points in the stress protocol. Neither age nor social support was associated with differences in the LF/HF ratio, which measures sympathetic modulation of heart rate. Conclusions: Social support is related to parasympathetic activity in UC. Given previous evidence of an antiinflammatory role for the parasympathetic nervous system, this suggests that autonomic function could serve as a mediating link between social support and reduced inflammatory activity.