0009 Characterizing Daily 24-hour Rhythmicity in Circulating Lipids in a Mixed Clinical Inpatient Population
Document Type
Conference Proceeding
Publication Title
SLEEP
Publication Date
5-2025
Meeting Name
SLEEP 2025
Meeting Date
June 8-11, 2025
Meeting Location
Seattle
Abstract/ Summary
Introduction
Circulating lipids are under control of the ~24-hour circadian clock in healthy individuals. How these rhythms are expressed in clinical populations, and whether they are altered by lipid-lowering medications (i.e., statins), is unknown. Methods
We assessed 24-hour rhythmicity in clinical lipid outcomes from ~187,000 samples collected as part of routine medical care of 27,706 hospitalized patients (45% female, mean [±SD] age 70.9 ± 15.1 years) with mixed medical diagnoses. Outcomes included total cholesterol, triglycerides, HDL-C and LDL-C. Blood samples were dichotomized as statin or no-statin use based on each patient’s prescription data. Cosinor regression was applied to hourly binned group-average time series data. Group averages were calculated either using all samples or stratified based on statin use. Results
Cholesterol, HDL-C, and LDL-C exhibited significant 24-hour rhythms with a single acrophase (i.e., time of fitted peak) in the late afternoon (~15:24–18:06 h). Triglycerides exhibited a principal acrophase in the early morning (~01:36 h) and a secondary peak in the afternoon (~13:36 h). The use of statins was associated with a significant reduction in amplitude for triglycerides (~300%), HDL-C (~40%) and LDL-C (~80%) but did not change cholesterol rhythm amplitude or the acrophase for any of the lipid rhythms. The timing of cholesterol, HDL-C and LDL-C rhythms in the clinical population were similar to the timing observed in young healthy individuals under controlled laboratory conditions, differing only by up to ~3 hours. Furthermore, the differing peaks observed in triglycerides under constant routine (morning peak) and ambulatory diurnal conditions (afternoon peak) were reflected in the dual peak observed in the clinical population, suggesting multiple mechanisms underlying clinical expression of triglyceride rhythms. Conclusion
Circulating lipids in an inpatient clinical population exhibited robust 24-hour daily rhythms. Rhythm amplitude but not timing was altered by statin use. The clinical data may reflect endogenous circadian variation in lipid timing for some outcomes, but understanding the mechanisms underlying rhythmic expression is necessary to interpret the timing of clinical or real-world data. Support (if any)
NIA: R03AG071922 (PI: Rahman / St. Hilaire) NHLBI: R01HL159207 (PI: Rahman)