Effect of Sleep Extension on Body Weight and Learning in Children (More2Sleep)

A Randomized Controlled Trial of Sleep Extension to Regulate Body Weight and Improve Learning in School-aged Children

More2Sleep is a randomized, controlled, parallel trial with two groups (sleep extension vs control) including 142 school-aged children (6-12 years) who have a BMI above average, defined as age- and sex-specific BMI Z-score above zero using WHO reference standards, and habitually sleep for ≤ 9 h/night. Data will be collected before and after a 3-month sleep extension intervention, and after a 6-month follow-up (at months 0, 3, and 9). The collection of data is mainly related to the main study. However, some optional examinations will be conducted on a first come, first serve basis, consisting of substudy-I (metabolic mechanisms, n=60) and substudy-II (learning mechanisms, n=142).

The primary objective is to assess the effects of sleep extension by ~45 min/night, achieved by going to bed 60-90 min earlier, on adiposity and learning ability in school-aged children who have a BMI for age and sex above average, and sleep less than recommended for their age.

Inclusion Criteria:

• Age: 6-12 years old (inclusive range).
• Weight status: having a BMI above average, defined as an age- and sex-specific BMI Z-score above zero using reference standards from the WHO.
• Sleep duration: sleeping ≤9 h/night on the basis of sleep diaries filled in by the children's parents, based on recommendations by the American Academy of Sleep Medicine and the Sleep Health Foundation.

Exclusion Criteria:

• Any genetic, neurological, endocrinological or psychiatric condition that affects growth, metabolism, eating behaviors, cognitive function, or body weight (for example: dwarfism, epilepsy, attention deficit hyperactivity disorder, head trauma, β-thalassemia, hypothyroid-ism, hyperthyroidism, type I diabetes).
• Any sleep-related disorder (for example: obstructive sleep apnea, parasomnias, narcolepsy, restless leg syndrome).
• Regular use of prescribed or over-the-counter medications that influence study outcomes.
• Irregular school schedule.
• If a child's parents live separately, the child is allowed to sleep at both households. How-ever, if one of the parents does not wish to carry out the sleep intervention and follow given instructions, then the child should only sleep at their household Friday, Saturday and/or Sunday night.
• In the circumstance where the child does not speak or understand Danish, the child's parents do not have to speak or understand Danish, as long as both parties can speak and understand English.
• Participation in other research studies.
• Metal implants and claustrophobia (only for substudy-II).