Association between objectively-measured sleep duration and early cardiac and hepatic imaging changes in adolescents: insights from the EnIGMA study
Authors: Real C , Parraga R , Martinez-Gomez J , Gonzalez-Calvo E , Garcia-Cocera M , De Cos-Gandoy A , Bodega P , De Miguel M , Beneito-Dura M , Fernandez-Alvira J M , Sanchez-Gonzalez J , Pizarro G , Garcia-Lunar I , Santos-Beneit G , Fernandez-Jimenez R 
Published: October 2024

Abstract

Introduction
Inadequate sleep duration (SD) has been associated with adverse cardiovascular (CV) events in adults and adiposity in all life stages. Furthermore, previous cross-sectional studies have shown a possible association between self-reported SD and cardiac structural alterations as detected with echocardiography and cardiovascular magnetic resonance (MR), even in young healthy people. However, there is a lack of longitudinal studies demonstrating an association between objectively-measured SD and structural cardiac alterations.

Purpose
To assess the association between SD and MR-derived cardiac and hepatic parameters in adolescents.

Methods
This study used longitudinal data collected as part of the SI! Program for Secondary Schools trial in Spain (2017-2021), which enrolled 1326 participants (mean age: 12.5±0.5 years at baseline). Measurements were taken at three different time-points: baseline, 2-year follow-up and 4-year follow-up. SD and physical activity were assessed by accelerometry for seven consecutive days at each follow-up. The participants were offered to undergo a MR scan in the final follow-up as part of the Early imaging markers of unhealthy lifestyles in adolescents (EnIGMA) study. The imaging protocol included a cine SSFP to provide images for chamber size and function, myocardial tagging acquisitions to assess myocardial strain, T1 and T2 mapping sequences to provide precise myocardial relaxation time properties, and a liver mDixonQuant sequence to obtain liver fat content, using a 3-T scanner. The cumulative effect of the independent variable (SD) and the covariates was assessed using the area under the curve (AUC) method, calculating the integral of the curve parameters during the follow-up period for each subject. To facilitate interpretation, AUC values were divided by the years of follow-up. The participants were included in the analysis if they had available data for SD in at least 2 of the 3 time-points. The association between SD and the MR parameters was assessed by linear regression models.

Results
109 participants (61 girls [56.0%]; mean age=16.0±0.5 years) were included in this study. Indexed left ventricular (LV) mass, as well as indexed end-diastolic biventricular volumes were higher in boys than in girls (Figure 1). SD AUC (hours/day) was independently and inversely associated with indexed LV mass and liver fat fraction in the unadjusted and adjusted (age, gender, physical activity, body mass index percentile, and systolic and diastolic blood pressure percentiles AUCs) models (Figure 2). There were no significant associations between the SD AUC and other MR-derived parameters.

Conclusion
Shorter SD is independently associated with initial stages of cardiac remodeling and liver fat accumulation as assessed with state-of-the-art MR as early as in adolescence. Considering these results, health promotion programs should be implemented early in life emphasizing the importance of good sleep habits.Participant characteristicsAssociation between SD and MR