Older men with disrupted circadian rhythm at higher risk for Parkinson’s
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Older men with a disrupted circadian rhythm had an increased risk for incident Parkinson’s disease, researchers wrote in JAMA Neurology.
The findings suggest the trait may represent an “important prodromal feature” for the neurological condition, Yue Leng, MD, PhD, assistant professor of psychiatry at the University of California, San Francisco Weill Institute for Neurosciences, and colleagues added.
In a longitudinal study of 2,930 community-dwelling older men, researchers studied the relationship between rest-activity rhythms — which were assessed objectively through wrist actigraphy — and the risk for developing Parkinson’s disease over an 11-year period. Specifically, they explored whether the relationship existed independently of sleep disturbances.
Leng and colleagues accounted for patients’ alcohol and caffeine intake, benzodiazepine use, BMI, cognitive function, demographic characteristics, depressive symptoms, educational level, physical activity and smoking status. They also looked at the men’s history of coronary heart disease, hypertension, stroke and type 2 diabetes.
They found that the risk for Parkinson’s disease increased with decreasing circadian amplitude, or the strength of the rhythm (OR for each 1-point standard deviation [SD] decrease = 1.77; 95% CI, 1.3-2.41); decreasing mesor, or the mean level of activity (OR for each 1-point SD decrease = 1.64; 95% CI, 1.22-2.21); and decreasing robustness, defined as how closely activity follows a cosine 24-hour pattern (OR for each 1-point decrease = 1.54; 95% CI, 1.14-2.07).
Further, men in the lowest quartile of amplitude, mesor or robustness had approximately three times the risk for developing Parkinson’s disease vs. those in the highest quartile of amplitude (OR = 3.11; 95% CI, 1.54-6.29) mesor (OR = 3.04; 95% CI, 1.54-6.01) and robustness (OR, 2.65; 95% CI, 1.24-5.66).
Importantly, the association remained after adjusting for nighttime sleep disturbances and duration in the lowest quartile vs. the highest quartile (amplitude OR = 3.56; 95% CI, 1.68-7.56; mesor OR = 3.24; 95% CI, 1.52-6.92; robustness OR = 3.34; 95% CI, 1.45-7.67). These associations were “somewhat attenuated, but the pattern remained similar” after removing Parkinson’s disease cases that evolved within 2 years after baseline in the lowest quartile vs. the highest quartile (amplitude OR = 2.4; 95% CI, 1.15-5; mesor OR = 2.76; 95% CI, 1.35-5.67; and robustness OR = 2.33; 95% CI, 1.07-5.07). Acrophase — the timing of peak activity — was not significantly associated with a risk for Parkinson’s disease, according to the researchers.
“To our knowledge, this study is the first to report a longitudinal association between circadian disruption and subsequent risk of [Parkinson’s disease] in community-dwelling older adults,” Leng and colleagues wrote.
They suggested that future studies should examine the underlying mechanisms and ascertain if circadian disruption itself might play a role in the onset of Parkinson’s disease.
“If confirmed to be a risk factor for [Parkinson’s disease], then circadian rhythmicity could be a promising intervention target and will open new opportunities for the prevention and management of [Parkinson’s disease],”researchers concluded.