Associations among integrated psychoneuroimmunological factors and metabolic syndrome

Abstract

Background: Metabolic syndrome (MetS) has been reported to cause considerable psychoneuroimmunology (PNI) disturbances such as, psychological distress, autonomic nervous imbalance, and impaired immune function. Associations among these psychoneuroimmunology (PNI) factors and their integrated effects with MetS and risk components of MetS necessitate further exploration.

Objective: This study investigated associations among psychoneuroimmunological factors, their integrated effects with MetS and risk components of MetS.

Methods: This was a cross-sectional study. Participants were recruited from two health management centers at a medical center in Northern Taiwan. Demographics and data on psychological distress (e.g., perceived stress and depression) were collected using self-reported questionnaires. Heart rate variability (HRV) and C-reactive protein values (CRP) were measured to evaluate participants' autonomic nervous function and immune reaction. The risk components of MetS (e.g., elevated blood pressure, impaired fasting glucose, dyslipidemia, and abdominal obesity) were identified according to the Taiwan-specific definition of MetS and were determined based on participants' health examination profiles.

Results: A total of 345 participants with complete data were included for data analysis. Compared with healthy controls, participants with MetS exhibited higher depression scores (11.2±8.5 vs. 8.7±7.0), higher CRP values (2.1±2.5 vs. 0.7±1.0), and lower HRV (total power: 758.7±774.9 vs. 1064.4±1075.0). However, perceived stress in participants with MetS did not significantly differ from that of their healthy counterparts (p>0.05). Univariate analyses indicated that associations among psychoneuroimmunological factors and MetS risk components were statistically heterogeneous: a) perceived stress and depression were significantly associated only with high blood glucose (p<0.05); b) CRP was significantly associated with all MetS risk components (p<0.05); and c) HRV was significantly associated with high triglycerides and high fasting blood glucose (p<0.05). Multivariate analysis indicated that the integrated effects of depression, CRP, and HRV were significantly associated with MetS (p<0.01) after controlling for age and education level.

Conclusions: Higher depression scores, higher CRP values, and lower HRV are independently and additively associated with MetS and risk components of MetS. Accordingly, a multidisciplinary approach to alleviating psychological distress, immune dysfunction, and autonomic nervous imbalance is recommended for promoting well-being in people with subclinical metabolic abnormalities or MetS to minimize downstream health consequences.

Keywords: Autonomic nervous function; Depression; Metabolic syndrome; Perceived stress; Psychological distress; Psychoneuroimmunology.