Abstract P301: Heart Rate Variability is Associated with Future Global Cognitive Performance: the Multi-Ethnic Study of Atherosclerosis

Abstract

Background: Low heart rate variability (HRV) is associated with major vascular risk factors for cognitive decline, including hypertension and cardiovascular disease (CVD). Therefore, we hypothesized that higher HRV during mid- to late-life is associated with better cognitive performance. Methods: In a subset of participants from the Multi-Ethnic Study of Atherosclerosis (N = 2,961; aged 45-84 years; 55% female; 40% white, 22% African-American, 25% Hispanic, and 13% Chinese-American), we used multivariate linear regression to study the relationship of short-term HRV to global cognitive performance as measured by the Cognitive Abilities Screening Instrument (CASI; score range 0-100). Two measures of HRV, the standard deviation of normal-to-normal intervals (SDNN) and root mean square of successive differences (RMSSD), were computed at Exam 1 (2000-2002) and Exam 5 (2010-2012). CASI was administered at Exam 5. Results: In age-, race-, sex- and education-adjusted models, Exam 1 SDNN was significantly associated with performance on the CASI ( β = 0.74 ± 0.22; P < 0.001). This association remained significant after adjustment for cardiovascular risk factors, including prevalent CVD, medication use, and APOE ε4 allele carriage ( β = 0.53 ± 0.23; P = 0.019). Furthermore, participants with highest quartile Exam 1 SDNN scored better than the adjusted mean CASI score (0.61 ± 0.22 points higher; P = 0.022), and 0.81 ± 0.29 points higher than other quartiles ( P = 0.006); participants in other Exam 1 SDNN quartiles scored similarly to each other and to the adjusted mean. In contrast, there were no associations between CASI score and Exam 5 SDNN, Exam 1 RMSSD, or Exam 5 RMSSD after adjustment for cardiovascular risk factors, and no interactions between HRV and race or APOE were present. Conclusions: Highest quartile 10-year antecedent SDNN is associated with better global cognitive performance in a multi-ethnic population of middle-aged and elderly adults, independent of sociodemographic factors, traditional cardiovascular risk factors, APOE status, and prevalent CVD. These results suggest that mid- to late-life HRV may be an early predictor of future cognitive ability.