Autonomic tone and C-reactive protein: a prospective population-based study.

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System
• Inflammation Biomarkers

Background:

• Cardiac autonomic tone, reflecting the balance between sympathetic and parasympathetic nervous system activity, plays a crucial role in cardiovascular health.
• C-reactive protein (CRP) is a key inflammatory marker associated with various chronic diseases.
• Understanding the interplay between autonomic dysfunction and inflammation is vital for developing effective health interventions.

Purpose of the Study:

• To investigate the cross-sectional and longitudinal associations between markers of cardiac autonomic tone and serum CRP levels.
• To explore potential causal relationships between autonomic tone and inflammation.

Main Methods:

• A prospective cohort study involving 188 middle-aged and older adults.
• High-frequency heart rate variability (HF) and pre-ejection period (PEP) were used to assess parasympathetic and sympathetic tone, respectively.
• Cardiac autonomic balance (CAB) was calculated, and serum CRP was measured using high-sensitivity enzyme immunoassay. Statistical analyses included multivariate regression and autoregressive cross-lagged panel models.

Main Results:

• Cross-sectional analyses revealed significant inverse associations between HF and CAB with ln CRP, even after adjusting for multiple covariates.
• Longitudinal analysis indicated that higher CRP levels in one year predicted greater increases in HF in the subsequent year.
• These findings suggest a dynamic relationship where inflammation may influence autonomic regulation.

Conclusions:

• The study confirms an inverse relationship between cardiac parasympathetic tone and CRP in cross-sectional analyses.
• Longitudinal data suggest that elevated circulating CRP may lead to an increase in cardiac parasympathetic tone over time.
• These results highlight a potential pathway through which inflammation impacts autonomic nervous system function.