Endocrine Abstracts

Introduction: This study aimed to examine whether altered Heart Rate Variability (HRV) could predict the risk of development of metabolic syndrome (MetSD) in Asians.

Methods: We investigated health checkup records of 33 752 adults aged 20–65 years old who did health checkups and HRV measurement between April 2011 and June 2014 at Kangbuk Samsung Hospital, without MetSD, anemia, thyroid disease, malignancy, and heart disease. A 3-minute HRV recording was performed while seating on a chair. We analyzed HRV in time domain (standard deviation of the normal-to-normal interval [SDNN, ms], root mean square difference [RMSSD, ms]), and frequency domain (total power [TP, 0–0.4 Hz, ms²], very low-frequency [VLF, ≤0.04 Hz, ms²], low-frequency [LF, 0.04–0.15 Hz, ms²], high-frequency [HF, 0.15–0.4 Hz, ms²] power, normalized LF, normalized HF, and LF : HF ratio). We compared the risk of incident MetSD between 2012 and 2016 using multivariate Cox analysis according to tertiles of HRV variables with tertile 1 as reference group. MetSD was determined by the presence of three or more of waist circumference ≥90 cm in men or ≥85 cm in women, fasting glucose ≥100 mg/dl or use of an anti-glycemic agent, triglyceride >150 mg/dl or use of an antihyperlipidemic agent, high-density lipoprotein-cholesterol <50 mg/dl in men, <40 mg/dl in women or use of an anti-hyperlipidemic agent, and blood pressure ≥130/85 mmHg or use of an antihypertensive drug.

Results: Mean age of subjects were 37.8±5.7 years. During 40 324 033 person-years, 4061 subjects were diagnosed with MetSD. Most of time and frequency domain variables were lower in MetSD group than nonMetSD group, whereas LF norm and LF/HF ratio were higher. In cox analysis, the risk of development of MetSD was significantly decreased as SDNN, RMSSD, TP, VLF, LF, HF, and HF norm tertiles increased. In case of LF norm and LF/HF ratio, positive relationship was observed. These tendencies were maintained in RMSSD, LF, and HF after adjustment for age, sex, body mass index, current smoking, systolic blood pressure, serum low-density lipoprotein-cholesterol, high sensitivity c-reactive protein, and glucose levels as confounders. Hazard ratios(95% confidence intervals) of tertile 3 were 0.83(0.76–0.91) for RMSSD, 0.92(0.85–0.99) for LF, and 0.90(0.82–0.98) for HF.

Conclusion: Decreased HRV can anticipate the risk of incident MetSD in young Asian adults.