lifestyle factors, population,the autonomic nervous system

Dysfunction of autonomic nervous system may contribute to neuronal damage. The research in this area is limited. We prospectively investigated whether decreased vagal modulation, indexed by high frequency heart rate variability (HF-HRV), in midlife predicts subsequent cognitive decline. Method: Data from the fifth (1997-1999), seventh (2002-2004) and ninth (2007-2009) phases of the UK Whitehall II longitudinal population-based cohort study were analysed. The sample size was 4471 (1247 women). Cognitive function measures included memory, reasoning, vocabulary, executive function and global cognition. Heart rate variability was obtained during 5 min of supine rest. The values of HF-HRV at phase 5 were divided into quartiles. Random mixed models were applied. Results: Over a 10 year period there was significantly greater decline in vocabulary (β=-0.15; p=0.001), reasoning, (β=-0.11; p=0.007), executive function (β=-0.09; p=0.033) and global cognition (β=-0.07; p=0.027 ) among men with baseline HF-HRV in the lowest quartile than others. Statistically insignificant associations were found in women. All models were adjusted for age, ethnicity and education. Further adjustments for known confounders including sociodemographic and lifestyle factors, cardiometabolic conditions and medication did not change the predictive effect of HRV on cognitive decline. Conclusion: Findings support an etiological role of the autonomic nervous system in cognitive decline.