Abstract MP04: Mean Heart Rate and Brain Morphology in Elderly Women Without a History of Cardiovascular Disease

Abstract

Background: Low resting heart rate (RHR) has been shown to be predictive of a lower risk for cardiovascular events. Accumulating evidence suggests that RHR may also be related to cognition later in life. To this point, data on the relationship with brain morphology in populations with none or few modifiable cardiovascular risk factors are largely missing. The aim of this study was to assess the associations between mean RHR and brain volumes in elderly postmenopausal women without a history of cardiovascular disease. Methods: The study sample consisted of postmenopausal women without a history of diabetes, coronary heart disease, stroke, atrial fibrillation and hypertension who were enrolled in the MRI ancillary study of the Women’s Health Initiative Memory Study (WHIMS-MRI). Women with very low (<40 bpm) or very high (>120 bpm) heart rate, suffering from any cancer, emphysema, history of pulmonary embolism or current smokers were excluded. Heart rate readings were taken at baseline (WHI enrollment, 1996-1998) and each annual follow-up visit. Brain MRI scans were performed between 2004-2006. Our final sample consisted of 493 women with a mean age of 69 years who were followed over a median of 8 years with an average of 8 RHR assessments. Results: In multivariate regression models adjusting for age, education, WHI Hormone Trial Randomization assignment (HTR arm), depression, physical activity, alcohol intake, coffee intake, presence of ApoE4 allele, mean systolic blood pressure over time, anti-hypertensive medication use over time and incident cardiovascular disease over time, women in the highest tertile of mean RHR (71-92/min) exhibited significantly higher lesion volumes compared to women in the lowest tertile (51-66/min). Conclusion: In postmenopausal women without a history of cardiovascular disease, high mean RHR was associated with higher white and grey matter lesion volumes later in life reflecting higher volumes of neuronal dysfunction and degeneration.