MULTIPLE METABOLIC SYNDROME IS ASSOCIATED WITH LOWER HEART-RATE-VARIABILITY - THE ATHEROSCLEROSIS RISK IN COMMUNITIES STUDY

OBJECTIVE - To test at the population level whether people with multip le metabolic syndrome (MMS) disorders have reduced cardiac autonomic a ctivity (CAA). RESEARCH DESIGN AND METHODS - We examined the associati on between the level of CAA and MMS disorders, at the degree of cluste ring and the segregate combination levels, using a random sample of 2, 359 men and women aged 45-64 years from the biracial, population-based Atherosclerosis Risk in Communities (ARIC) Study. Supine resting 2-mi n beat-to-beat heart rate data were collected. High-frequency (HF) (0. 15-0.35 Hz) and low-frequency (LF) (0.025-0.15 Hz) spectral powers, th e ratio of LF to HF; and the SD of all normal R-R intervals (SDNN) wer e used as the conventional indices of heart rate variability (HRV) to measure CAA. The MMS disorders included hypertension, type 2 diabetes, and dyslipidemia. RESULTS - HRV indices were significantly lower in i ndividuals with MMS disorders. The multivariable adjusted mean HF was 0.85 (beat/min)(2) in subjects with all three MMS disorders, in contra st to 1.31 (beat/min)(2) in subjects without any MMS disorder. At the segregated combination level, the multivariable adjusted means +/- SEM of HF were 1.34 +/- 0.05, 1.16 +/- 0.05, 1.01 +/- 0.17, and 1.34 +/- 0.05 (beat/min)(2), respectively, for subjects without any MMS disorde r, with hypertension only, with diabetes only, and with dyslipidemia o nly, and the means +/- SEM of HF were 0.93 +/- 0.04, 0.70 +/- 0.15, an d 1.20 +/- 0.05 (beat/min)(2), respectively, for subjects with diabete s and hypertension, diabetes and dyslipidemia, and hypertension and dy slipidemia. An increase in fasting insulin of 1 SD was associated with 88% higher odds of having a lower HF: The pattern of associations was similar for LF and SDNN. CONCLUSIONS - These findings suggest that MM S disorders adversely affect cardiac autonomic control and a reduced c ardiac autonomic control may contribute to the increased risk of subse quent cardiovascular events in individuals who exhibit MMS disorders.