The association of heart-rate variability with cardiovascular risk factorsand coronary artery calcification - A study in type 1 diabetic patients and the general population

OBJECTIVE - To examine the association of heart-rate variability viith card iovascular risk factors and coronary calcification in type 1 diabetic and n ondiabetic subjects without a history of cardiovascular disease. Reduced he art-rate variability is associated with increased risk of coronary events. Whether it is associated with coronary atherosclerosis is unknown. RESARCH DESIGN AND METHODS - Power spectral analysis was used to define hea rt-rare variability in a cross-sectional study of 160 type 1 diabetic patie nts and 163 randomly selected nondiabetic adults from the general populatio n aged 30-55 years. Coronary artery calcification was measured using electr on beam-computed tomography. RESULTS - Reduced heart-rate variability was associated with similar risk f actors in the diabetic and nondiabetic subjects, namely higher HbA(1c), tri glycerides, systolic blood pressure, BMI, and albumin excretion rate. Reduc ed heart-rate variability was significantly associated with coronary artery calcification in all subjects (odds ratio per tertile lower total power = 1.5, P = 0.01). This association was not independent of blood pressure or B MI (odds ratio on adjustment = 1.3, P = 0.1). CONCLUSIONS - Reduced heart-rate variability clusters with other cardiovasc ular disease risk factors, especially those that are more common in the ins ulin resistance syndrome, and is associated with increased coronary calcifi cation in asymptomatic young adults. Whether reduced heart-rate variability leads to other risk factor disturbances or mediates the effects of other r isk factors on atherosclerosis deserves further study.