Longitudinal Analysis of Sleep Duration and Cardiometabolic Risk in Young Children

BACKGROUND: The aim of this study is to determine if sleep duration in early childhood is associated with cardiometabolic risk (CMR) in later childhood as assessed by a CMR cluster score [sum of age- and sex-standardized z-scores of waist circumference (WC), systolic blood pressure, triglycerides, glucose, and (inverse) high-density lipoprotein (HDL)]. Secondary objectives included examining sleep duration and the individual CMR factors and BMI z-score. PATIENTS AND METHODS: A prospective cohort study was conducted using data from the TARGet Kids! practice-based research network in Toronto, Canada. Children (n = 597) with parent-reported 24-hour sleep duration in early childhood (12-36 months) and a follow-up visit (36-96 months) with all five CMR factors were included in the analysis. Multivariable linear regression was used to assess the relationship between early childhood sleep duration and later childhood CMR, adjusting for relevant covariates. RESULTS: Average 24-hour sleep duration in early childhood [mean age: 28.1 (6.6) months] was 11.8 (1.4) hours, with 87% meeting or exceeding total sleep recommendations for their age. Sleep duration in early childhood was not associated with the CMR cluster score in later childhood. Shorter sleep duration was associated with higher HDL concentrations [adjusted β = -0.028 (95% confidence interval: -0.049 to -0.007), p = 0.009]. CONCLUSIONS: Further research is needed to determine if early childhood sleep duration is associated with HDL in later childhood. Future studies, which investigate sleep quality in addition to sleep duration, may be helpful.