Associations of psychosocial factors with heart rate and its short-term variability: Multi-ethnic study of atherosclerosis

OBJECTIVE: To examine the association of psychosocial factors with heart rate (HR) and its variability across multiple ethnic groups and by gender. Increased HR and reduced HR variability are markers of increased cardiovascular risk. METHODS: Between 2000 and 2002, 6814 men and women (2624 Whites, 1895 African-Americans, 1492 Hispanics, and 803 Chinese) aged 45 to 84 years took part in the first examination of the Multi-Ethnic Study of Atherosclerosis. Associations of psychosocial variables with mean values of HR and its short-term variability were tested, using multivariate regression models. RESULTS: In age, gender, race/ethnicity, and risk factor-adjusted analyses, a depressive symptom score was positively associated with HR and inversely associated with HR variability (standard deviation of normal-to-normal (N-N) interbeat intervals (SDNN) and the root mean square of successive differences in N-N intervals (RMSSD)). The adjusted mean differences per 1-SD (8 points) increment of depression score for HR, RMSSD, and SDNN were 0.5 (95% confidence interval (CI), 0.2-0.7), -0.8 (95% CI, -1.5 to -0.2), and -0.7 (95% CI, -1.1 to -0.2). The social support score was inversely associated with HR, but nonsignificantly associated with RMSSD and SDNN. There was no association of trait anger or trait anxiety with HR, RMSSD, or SDNN. Associations were generally consistent in men and women. CONCLUSIONS: These findings generally support the hypothesis that depression may be associated with increased HR and reduced HR variability, which increase the risk of cardiovascular diseases.