Association of Rest-Activity Rhythm and Sleep Regularity With Cardiometabolic Disease in the CAR

18 Mar 20264 min read0 viewsJournal Feed

GIST (Key Takeaways)

Journal of the American Heart Association, Ahead of Print. Background. Disrupted circadian rhythms are associated with cardiometabolic disease.
We examined associations between rest‐activity rhythms and cardiometabolic disease by race. Methods. In cross‐sectional analysis of the CARDIA (Coronary Artery Risk Development in Young Adults) sleep ancillary study (2020–2023), 861 participants wore wrist actigraphy for 7 days.
Sleep Regularity Index and rest‐activity rhythm measures were calculated: interdaily stability, intradaily variability, relative amplitude, and most active 10‐hour and least active 5‐hour period start times. Cardiometabolic disease markers included body mass index, waist circumference, blood pressure, hypertension, fasting glucose, estimated insulin resistance, and diabetes. Linear regression models with interaction terms evaluated effect modification by race.
Results. Among 354 Black and 507 White participants, the most consistent associations were between anthropometric markers and rest‐activity rhythms. Except for most active 10‐hour start, remaining indices and Sleep Regularity Index were associated with body mass index with β coefficients ranging from −1.74 to 0.86, consistent with our hypothesis that weaker rest‐activity rhythms relate to larger body mass index.

This cross-sectional analysis from the CARDIA sleep ancillary study (2020–2023) investigates whether rest–activity rhythms and sleep regularity relate to cardiometabolic disease markers, with examination of potential racial differences between Black and White participants.

Population: 861 participants with actigraphy data for seven days, comprising 354 Black and 507 White individuals.
Rhythm metrics: Sleep Regularity Index; rest–activity rhythm indices including interdaily stability, intradaily variability, relative amplitude; and start times for the most active 10-hour and least active 5-hour periods.
Cardiometabolic markers: body mass index (BMI), waist circumference, blood pressure metrics, hypertension status, fasting glucose, estimated insulin resistance, and diabetes status.

Linear regression models with interaction terms assessed whether associations differed by race.
Primary focus on the strength and direction of relationships between rhythmic measures and anthropometric, glycemic, and blood pressure markers.

The direction and magnitude aligned with weaker rhythms corresponding to higher BMI.

Similar patterns emerged for waist circumference.

Anthropometric associations: Most rest–activity indices, aside from the most active 10-hour start, and the Sleep Regularity Index, showed associations with BMI.
Race-specific patterns: Some effect modification by race was evident, particularly for relative amplitude’s association with BMI, stronger in White participants (notably: White β ≈ −2.63 versus Black β ≈ −1.24).
Glycemic markers: Disrupted circadian indices tended to associate with glycemic measures, with findings generally consistent across race groups.
Blood pressure: Associations between rest–activity rhythms and blood pressure were less consistent overall and across racial subgroups.

The data suggest weaker rest–activity rhythms and irregular sleep relate to less favorable anthropometric and glycemic profiles, with limited and inconsistent links to blood pressure and only modest racial differences.
The cross-sectional design limits causal inference, and several metrics showed variable strength across outcomes and racial strata.