Abstract P367: Regularity in Sleep and Eating Timing is Associated With Decreased Carotid Intima-Media Thickness in Healthy Young Adults

Abstract

Introduction: Greater regularity in daily sleep and eating timing are independently and separately associated with lower carotid intima-media thickness (CIMT), a marker of subclinical atherosclerotic development in early adulthood. Not known is the extent to which achieving regularity in both sleep and eating would be associated with a lower CIMT as compared to achieving regularity in either behavior alone, or neither. Such information could help identify behavioral target priorities for cardioprotective interventions. Hypothesis: We tested the hypothesis that individuals achieving both sleep and eating regularity would have a lower CIMT than individuals with either sleep or eating regularity, or neither. Methods: Healthy adults aged 18-45 years (N=65, 29.7±7.2 years, 63% female) completed 14 days of sleep and dietary assessments via wrist accelerometry and photo-assisted diet records, respectively. Mean time for sleep midpoint (midpoint time between sleep onset and offset) and caloric midpoint (time at which 50% of total daily calories are consumed), sleep regularity (i.e., a mean sleep midpoint standard deviation (SD) of <60 minutes), and eating regularity (i.e., caloric midpoint SD < median of 154 minutes) values were generated. A 4-level ‘sleep and eating regularity’ variable was generated that distinguished between participants achieving regularity in: (1) both sleep and eating, (2) only eating, (3) only sleep, or (4) neither. A linear regression model evaluating the association between sleep and eating regularity with CIMT adjusting for age, sex, systolic blood pressure, sleep duration, and total energy intake was estimated. Results: Participants who achieved regularity in both sleep and eating (n=23) had the lowest M CIMT =0.523mm (SD=0.043), those who achieved only sleep regularity (n=10) had a M CIMT =0.549mm (SD=0.078), only eating regularity (n=16) had a M CIMT =0.568mm (SD=0.065), and those achieving neither sleep or eating regularity (n=16) had the highest M CIMT =0.575mm (SD=0.074). In a controlled model, the 4-level sleep and eating regularity variable was significantly associated with CIMT (F=2.95, p=.04, model R 2 =.33), with regularity in both demonstrating pairwise significance as compared to neither (p = 0.02) and eating regularity only (p = 0.02). Given that a 1-SD increase in CIMT (~0.06-0.07mm) has been shown to confer a 40% increased risk for first-time CVD events in adults <45 years old, the ~0.05mm difference in CIMT between regular vs. irregular groups has clinical meaning. Conclusions: Regularity in sleep and eating may be associated with lower subclinical atherosclerosis as early as young adulthood. Future studies evaluating the cardioprotective effects of promoting regularity of modifiable behaviors (eating and sleep) in adults at elevated CVD risk are warranted.