The Atherosclerosis Risk in Communities (ARIC) Study
The objective of this study was to test prospectively in a population sample whether individuals with impaired heart rate variability (HRV) are at increased risk of developing coronary heart disease (CHD) and of non-CHD mortality and to test whether this relationship is more pronounced among individuals with diabetes. We examined the association between HRV and incident CHD and non-CHD mortality in a cohort of 11,654 men and women aged 45–64 years at intake, from the biracial, population-based Atherosclerosis Risk in Communities Study. Supine, resting, 2-min beat-to-beat heart rate data were collected at the baseline examination. High frequency (HF; 0.15–0.40 Hz) and low frequency (LF; 0.04–0.15 Hz) spectral powers, LF/HF ratio, normalized HF and LF, the standard deviation of all normal R-R intervals (SDNN), and the mean of the sum of the squared differences between adjacent normal R-R intervals (MSSD) were used as the conventional indexes of HRV to measure cardiac autonomic control. From this cohort, 635 cases of incident CHD (including 346 cases of incident myocardial infarction [MI] and 82 cases of fatal CHD), and 623 non-CHD deaths were identified and validated after an average of 8 years of follow-up. Among individuals with diabetes, the multivariable adjusted proportional hazards ratios (95% CI) were 2.03 (1.28–3.23), 1.60 (1.12–2.27), 1.50 (0.65–3.42), and 1.27 (0.84–1.91) for incident MI, incident CHD, fatal CHD, and non-CHD deaths, respectively, comparing the lowest quartile to the upper most three quartiles of HF. A similar pattern of associations was found for LF, SDNN, and MSSD. By contrast, there was no consistent pattern of associations among individuals without diabetes. At the population level, a lower HRV (reflective of impaired cardiac autonomic control) is statistically significantly related to the development of CHD among individuals with diabetes, independent of markers of the duration/severity of the glucose metabolism impairment. These data suggest a contribution of an impaired cardiac autonomic control to the risk of CHD among individuals with diabetes.
Address correspondence and reprint requests to Dr. Duanping Liao, Department of Health Evaluation Sciences, Pennsylvania State University College of Medicine, A210, 600 Centerview Dr., Hershey, PA 17033. E-mail:.
Received for publication 11 June 2001 and accepted in revised form 28 August 2002.
ARIC, Atherosclerosis Risk in Communities; CHD, coronary heart disease; ECG, electrocardiogram; HF, high frequency; HFnu, normalized HF; HRV, heart rate variability; LF, low frequency; LFnu, normalized LF; MI, myocardial infarction; MSSD, mean of the sum of the squares of differences; PSD, power spectral density; SDNN, standard deviation of all normal R-R intervals; TP, total HRV power; VLF, very low frequency.