BP Variability and Cardiovascular Autonomic Function in Relation to Forced Expiratory Volume: A Population-Based Study.

Background Cardiovascular autonomic dysfunction is associated with increased incidence of cardiovascular diseases (CVD). This population-based study explored whether low FEV(1) or low vital capacity (VC) is associated with autonomic dysfunction, as measured by the spontaneous heart rate variability (HRV) and systolic BP variability (SBPV). Methods SBPV and HRV were recorded during 5 min of controlled breathing in men and women, aged 70 years. FEV(1) and VC were recorded in 901 subjects. Of them, information on HRV and SBPV was available in 820 and 736 subjects, respectively. Measures of autonomic function, ie, SBPV in the low-frequency (LF) and high-frequency (HF) domains, HRV and baroreceptor sensitivity (BRS), were studied in sex-specific quartiles of FEV1 and VC. Results Low FEV(1) was associated with high SBPV in the HF domain. Mean SBPV-HF was 5.2, 4.5, 4.1 and 3.8 mm Hg, respectively, in subjects with FEV(1) in the first (low), second, third and fourth quartile (trend: p < 0.001). This relationship persisted after adjustments for potential confounding factors. Low VC was significantly associated with high SBPV-HF in the crude analysis, but not after adjustment for confounding factors. Neither FEV(1) nor VC showed any significant relationship with BRS, HRV or SBPV in the LF domain. Conclusion In this population-based study, low FEV(1) was associated with high systolic BP variability in the HF domain. It is suggested that high beat-to-beat variability in BP could contribute to the increased cardiovascular risk in subjects with moderately reduced FEV(1).