Relationship between Sleep and Obesity among Children in the Guelph Family Health Study

The purpose of this study was primarily to examine the cross-sectional and longitudinal associations between sleep measures (duration, quality, and variability) with markers of obesity risk (BMI, BMIz, waist circumference, body composition and blood pressure) among child participants in the Guelph Family Health Study. Additionally this study aimed to examine the extent to which children participants who receive the Guelph Family Health Study intervention improve their sleep quantity, quality and variability, compared to a control group. Sleep was measured using wrist Actigraphy for 2-7 nights. There were 46 and 30 participants included in the primary and secondary objective respectively. Children were between the ages of 18 months and five years old and the majority identified as Caucasian. Results showed no significant associations in the cross-sectional analyses between sleep measured and markers of obesity risk. In the longitudinal analyses, increases sleep efficiency from baseline to 6-months were associated with lower BMI z-scores at 6-months and lower sleep variability was associated with lower BMI and BMI z-scores at 6-months after adjusting covariates. Greater decreases in sleep variability were also associated with lower waist circumference at 6-months however this association did not remain after adjusting for covariates. In the secondary objective, no significant associations were found between intervention groups with regard to sleep measures. This study provides preliminary evidence suggesting an important role of sleep quality and sleep variability as predictors of obesity risk in preschool children.