Objectives To investigate the relationship of leptin and adiponectin with heart rate variability (HRV).
Method Leptin and adiponectin levels were measured in 388 non-diabetic officers from the Buffalo Cardio-Metabolic Occupational Police Stress study, following a 12-hour fast. HRV was performed according to methods published by the Task Force of the European Society of Cardiology and the North American Society of Pacing Electrophysiology for measurement and analysis of HRV. Mean values of high (HF) and low frequency (LF) HRV were compared across tertiles of leptin and adiponectin using ANOVA and ANCOVA; trends were assessed using linear regression models.
Results Leptin, but not adiponectin, was significantly and inversely associated with HF and LF HRV. BMI and percent body fat (also waist circumference and abdominal height) significantly modified the association between leptin and LF (but not HF) HRV. Among officers with BMI <25 kg/m2, the association between leptin and HRV was not significant. However, among officers with BMI ≥25 kg/m2, the association between leptin and HRV was inversely related, after adjustment for age, gender, and race/ethnicity; p-values for trend (HF HRV, p = 0.019 and LF HRV, p < 0.0001). Similarly, among officers with percent body fat ≥25.5%, leptin and LF HRV showed significant, inverse associations (adjusted p for trend = 0.001).
Conclusions Our results show that leptin levels were inversely and significantly associated with HRV among all officers, and particularly among officers with higher levels of adiposity. These results suggest that increased leptin levels may be associated with CVD-related health problems.