Abstract P042: Impact Of Mild Sleep Restriction On Lipid Profile: Influence Of Inflammatory Markers

Abstract

Introduction: Short sleep duration is associated with an increased risk of cardiovascular disease (CVD). Dyslipidemia is one of the main risk factors for CVD but the influence of sleep duration on this risk factor is, for the moment, inconclusive. Objective: The goal of this study is to test the impact of mild sleep restriction (SR), sustained for 6 wk, on the lipid profile of participants at risk of CVD. Methods: A randomized crossover study was carried out in 64 adults (68% women) aged 20-73 y with a BMI between 19.2-29.9 kg/m 2 . Participants habitually slept ≥7 h/night, verified by 2 wk of wrist actigraphy during screening. Participants underwent 2 sleep conditions of 6 wk each: AS and SR (a reduction of 1.5 h/night relative to AS). Lipid profile was determined from fasted blood samples collected at baseline, wk 3, wk 4 and wk 6 of each phase. In a subset of 34 women, we analyzed inflammatory markers: interleukin- 6 (IL-6), C-reactive protein (CRP) and tumor necrosis factor α (TNF-α). Linear mixed models were used to test the influence of sleep condition on change in lipid profile over time. We further performed Pearson correlations between change in inflammatory markers over each of the the 6-wk phases with lipids measures assessed at endpoint of the respective condition. Results: No effect of sleep condition on change in total cholesterol and triglyceride concentrations (β=0.40±1.80; p=0.83; β=0.43±2.38; p=0.86, respectively) was observed. LDL-C decreased over time, and this was more pronounced in SR compared to AS (β=-3.75±1.59; p=0.019). Similarly, HDL-C decreased over time, and this was less pronounced in SR compared to AS (β=1.78±0.64; p=0.006). Findings were similar in sub-group analyses by sex and menopausal status. Correlation analyses revealed trends for inverse correlations between IL-6 and total cholesterol (r=-0.299; p= 0.096), and LDL-C (r=-0.344; p=0.054) during SR. Also, a decrease in CRP during SR was correlated with higher HDL-C levels at endpoint (r=-0.545; p= 0.002). Conversely, in AS, we only detected a positive correlation between change in CRP and LDL-C at endpoint (r=0.354; p= 0.037). Conclusions: Six weeks of mild sleep restriction does not adversely impact lipid profile. However, this may be a maladaptive response to increases in inflammatory markers after a period of mild sleep restriction. Further studies are needed to confirm these findings.