Effect of the IDEFICS multilevel obesity prevention on children's sleep duration.

Background: According to recent findings, short sleep duration is associated with overweight in children. However, primary prevention efforts aimed at achieving adequate sleep among children are scarce. Therefore, the 'Identification and prevention of Dietary-induced and lifestyle-induced health EFfects In Children and infantS' (IDEFICS) study implemented a multilevel intervention that included sleep duration as a key behavioural target. The aim of this study is to evaluate sleep duration among children participating in the IDEFICS study. Methods: The IDEFICS nocturnal sleep intervention was included as part of stress reduction educational messages aimed at parents and children. Sleep was assessed by a parental 24-h recall (only weekdays; n = 8,543) and by a diary (weekdays and weekends separately; n = 4,150). Mixed linearmodels tested the intervention effect on sleep duration change between baseline when childrenwere 2-9.9 years of age (2007/2008) and follow-up (2009/2010). Logistic mix models were used to study the intervention effect on the presence of TV in the children's bedroom (one of the intervention messages; n = 8,668). Additionally, parents provided qualitative data regarding exposure to the intervention. Results: About 51.1% of the parents in the intervention regions reported awareness of the sleep intervention. A small intervention effect was seen on weeknight sleep duration in that the decrease in sleep duration over 2 years was smaller in the intervention (15 min) as compared with control regions (19 min) (p = 0.044). There was no overall intervention effect on weekend sleep duration or on the presence of a TV in the bedroom. A small significant time effect between baseline and follow-up was found on bedroom TV presence depending on self-reported intervention exposure (3% increase in TV presence in exposed versus 6.6% increase in non-exposed). Children without a TV in the bedroom had longer nocturnal sleep duration. Discussion: The sleep component of the intervention did not lead to clinically relevant changes in sleep duration. Future interventions aimed at young children's sleep duration could benefit frommore specific and intensemessaging than that found in the IDEFICS intervention. Future research should use objective measures of sleep duration as well as intermediate outcomes (sleep knowledge, sleep environment and sleep practices).