Abstract 2670: Depression and Heart Rate Variability: Is there a Common Genetic Pathway?
INTRODUCTION. Reduced heart rate variability (HRV), a measure of autonomic dysfunction, is associated with depression in CAD patients. However, there are few studies in persons free of CAD and little is known about whether depression and HRV share common genetic pathways.
METHODS. We performed power spectral analysis on 24-hour ambulatory ECGs in 254 male twins (98 pairs and 58 singletons) born between 1946 and 1956 (mean age 54) free of symptomatic CAD and diabetes. Log-normalized ULF, VLF, LF and HF power were calculated. Current depressive symptoms were defined as a Beck Depression Inventory (BDI) score ≥10. Lifetime history of major depression was determined with the Structured Clinical Interview for Psychiatry Disorders.Mixed-effect models were used to account for intra-pair variability and separate within- and between-pair effects.
RESULTS. Twins with higher BDI scores were more often smokers, physically inactive and had higher waist/hip ratio. ULF, VLF and total power, but not LF and HF, were associated with depressive symptoms (all p<0.01) even in the absence of a lifetime diagnosis of major depression. Within-pair analyses comparing depressed twins to their non-depressed co-twins showed consistent effects in DZ pairs and no effects in MZ pairs (Table⇓). The within-pair DZ differences persisted even after adjustment for smoking, coffee drinking, physical activity, abdominal obesity and heart rate.
CONCLUSIONS. Depressive symptoms are associated with decreased HRV in the lower frequencies in individuals free of CAD. This association is due, in part, to shared genetic effects between depression and HRV.