Study Links Circadian Rhythm Disruptions to Increased Dementia Risk

Wendy Wang, Ph.D., M.P.H., an Assistant Professor of Epidemiology, emphasized that circadian rhythms function as the body's internal clock, regulating physiological processes over a 24-hour period. She co-led the study with Lin Yee Chen, M.B.B.S., M.S., a Professor of Medicine at the University of Minnesota.

Dr. Wang noted that the research showed altered rest-activity rhythms in community-dwelling adults might increase dementia risk. This study is notable for utilizing accelerometer data from a chest-worn electrocardiogram (ECG) monitor to assess these rhythms, an approach that had not been previously applied to dementia risk.

The researchers evaluated data from the Atherosclerosis Risk in Communities (ARIC) Study, involving more than 2,000 participants who had no prior dementia diagnosis and wore ambulatory ECG monitors for up to two weeks between 2016 and 2017. The monitors assessed various aspects of daily activity, including the intensity of activity cycles, the fragmentation of these cycles, and the timing of peak activity.

Following an average follow-up of three years, 176 participants developed dementia. The analysis, after accounting for variables such as age, education, cardiovascular risk factors, and genetic susceptibility (APOE ε4), revealed that weaker daily rhythms, increased fragmentation, and later peak activity times correlated with a greater likelihood of developing dementia.

Dr. Wang explained that disruptions in circadian rhythms might affect processes like oxidative stress regulation or inflammation, which can lead to dementia. The study participants were diverse in terms of race, with an average age of 79, including nearly one-quarter identifying as Black, adding important context to dementia risk patterns in previously underrepresented populations, especially in late adulthood.

The researchers highlighted that the common use of ambulatory heart monitors in clinical settings could aid in assessing dementia risk in the future, but urged caution, indicating that further studies are necessary before clinical application.

Dr. Wang suggested that future research should explore circadian rhythms earlier in life, given the prolonged preclinical phase of dementia. The findings also lay the groundwork for examining whether interventions such as light therapy or lifestyle changes could enhance circadian rhythms and potentially mitigate dementia risk.

The study received funding from multiple sources, including the National Heart, Lung, and Blood Institute and the National Institute on Aging, among others.