Sleep duration and metabolic syndrome: An updated systematic review and meta-analysis
Authors: Yun Li
Yajun Zhang
Alexandros N Vgontzas
Xiangdong Tang
Chongtao Xu
Jing Xie
Maria Basta
Baixin Chen
Journal: Sleep Medicine Reviews (2021)
Discipline: NEUROSCIENCE & BEHAVIOR
Keywords: Long sleep; Metabolic syndrome; Short sleep; Sleep duration.
Affiliations: Department of Sleep Medicine, Shantou University Mental Health Center, Shantou University Medical College, Shantou, China; Sleep Medicine Center, Shantou University Medical College, Shantou, China., Department of Sleep Medicine, Shantou University Mental Health Center, Shantou University Medical College, Shantou, China; Sleep Medicine Center, Shantou University Medical College, Shantou, China. Electronic address: ., Sleep Research & Treatment Center, Department of Psychiatry, Pennsylvania State University, College of Medicine, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, USA., Sleep Medicine Center, Shantou University Medical College, Shantou, China., Sleep Medicine Center, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China.

Abstract:  We examined the association between self-reported sleep duration and metabolic syndrome (MetS). Data were collected from 36 cross-sectional and 9 longitudinal studies with a total of 164,799 MetS subjects and 430,895 controls. Odds ratios (ORs) for prevalent MetS and risk ratios (RRs) for incident MetS were calculated through meta-analyses of adjusted data from individual studies. Short sleep duration was significantly associated with increased prevalent MetS (OR = 1.11, 95% CI = 1.05-1.18) and incident MetS (RR = 1.28, 95% CI = 1.07-1.53) in cross-sectional and longitudinal studies, respectively. Furthermore, long sleep duration was significantly associated with increased prevalent MetS in cross-sectional studies (OR = 1.14, 95% CI = 1.05-1.23), but not incident MetS (RR = 1.16, 95% CI = 0.95-1.41) in longitudinal studies. Interestingly, the association between long sleep and prevalent MetS was found in sleep duration defined by 24-h sleep (including naps) rather than nighttime sleep. Our findings suggest 1) a "U-shape" relationship between sleep duration and MetS in cross-sectional studies and 2) association between short sleep duration, but not long sleep duration with incident MetS. Future studies should shed light on the underlying mechanisms related to the association between sleep duration and MetS and examine if normalizing sleep duration reduces MetS risk in the general population. 

Retracted: No

PubPeer comments:
 Figure 4. * Many of the  comets in panel GIII look remarkably similar to each other.  , 
 Figure 6. * Yellow boxes: Panels A (Group I-ND) and B (Group II-ND + FVU) appear to show an overlap, albeit stretched differently  , 
 Figure 5. The RT-PCR bands and plots in Figure 5 from this paper look remarkably similar to those in Figure 2 of another paper by the same authors, i.e. P. A. Janeesh and Annie Abraham, Plants Foods Hum Nutr (2013), DOI: 10.1007 s11130-013-0345-1 Note the presence of multiple similar looking lanes within the same GAPDH photos, and the similar distribution of the bar plots and the consistently small Standard Deviations over all plots.  ,