Autonomic dysfunction: a link between depression and cardiovascular mortality? The FINE Study.

BACKGROUND

Depression is associated with an increased risk of cardiovascular diseases (CVD) in vascular patients as well as in the general population. We investigated whether autonomic dysfunction could explain this relationship.

DESIGN

The Finland, Italy and The Netherlands Elderly (FINE) Study is a prospective cohort study.

METHODS

Depressive symptoms were measured with the Zung Self-rating Depression Scale in 870 men, aged 70-90 years, free of CVD and diabetes in 1990. Resting heart rate was determined from a 15-30-s resting electrocardiogram in The Netherlands and Italy and as pulse rate in Finland. In addition, in The Netherlands, heart-rate variability (HRV) and QTc interval were determined.

RESULTS

At baseline, depressive symptoms were associated with an increase in resting heart rate, and nonsignificantly with low HRV and prolonged QTc interval. After 10 years of follow-up, 233 (27%) men died from CVD. Prospectively, an increase in resting heart rate with 1 SD was associated with an increased risk of cardiovascular mortality [hazard ratio (HR), 1.22; 95% confidence interval (CI), 1.08-1.38]. In addition, low HRV (HR, 0.78; 95% CI, 0.61-1.01) and prolonged QTc interval (HR, 1.28; 95% CI, 1.06-1.53) per SD were associated with cardiovascular mortality. The increased risk of depressive symptoms for cardiovascular mortality (HR, 1.38; 95% CI, 1.21-1.58) did not change after adjustments for several indicators of autonomic dysfunction.

CONCLUSION

This study suggests that mild depressive symptoms are associated with autonomic dysfunction in elderly men. The increased risk of cardiovascular mortality with increasing magnitude of depressive symptoms could, however, not be explained by autonomic dysfunction.