The Role of Vitamin D in Sleep Disorders of Children and Adolescents: A Systematic Review.

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• Vitamin D plays an important role in the sleep quality of children. Healthcare practitioners may wish to establish vitamin D status in children presenting with sleep disturbances.

Introduction

Vitamin D levels have been associated with improved sleep in adults, but few studies have concentrated on the paediatric population. In order to identify if vitamin D plays a role regulating sleep in children and adolescents the paper reviewed studies, which looked at vitamin D in relation to sleep duration and quality of sleep. This included the following sleep disorders: obstructive sleep apnoea (OSA), restless leg syndrome (RLS) and insomnia.

Methods

• A broad systematic review following the PRISMA guidelines and using PubMed and Cochrane databases
• Search identified 748 papers. After exclusions for non-relevance, incorrect age group, or lack of data on sleep, 14 papers were included
• Due to the shortage of papers on this topic none of these papers were excluded, regardless of quality
• The participants in each study varied from 39 to 5289.

Results

The results highlighted:

• Plasma levels of vitamin D affect sleep duration and quality of sleep in children. Data taken from 5 studies
• Vitamin D cord blood levels were correlated to sleep in preschool children. Partly this was due to the mother’s vitamin D level during pregnancy affecting the level of vitamin D available to the foetus. Venous blood vitamin D level was linked to the sleep wake cycle of children. Data taken from 2 studies
• OSA was more likely to develop in children who had low vitamin D levels with a risk of 14.16% compared to a control group of 5.83% (1 study)
• Vitamin D supplementation was found to reduce neuron damage caused by hypoxia (1 study)
• An association exists between parental vitamin D insufficiency and their child’s vitamin D status (1 study). Data taken from 5 studies
• Vitamin D levels in specific diseases, such as coeliac disease (CD) showed a negative correlation with RLS
• For familial Mediterranean fever (FMF) vitamin D deficiency reduced sleep quality (36.5%). Data taken from 2 studies.

Conclusion

Notwithstanding the small number of studies, the review shows vitamin D deficiency, defined as <20 ng/mL, is associated with an increased risk for sleep disorders in children.

• Due to the role vitamin D plays in sleep in children, establishing vitamin D status may be useful for children presenting with sleep disturbances
• Adequate vitamin D levels during pregnancy are important to establish a vitamin D pool in the foetus
• Vitamin D supplementation is something to rule out in the case of OSA and associated hypoxia, metabolic dysfunction and systemic inflammation in children
• Due to the negative impact poor sleep has on the body, improving sleep quality at a young age could form an important part of preventative health care.

• Additional studies are required to support the conclusion in this study
• Due to the low number of studies, any additional research should be of a high standard and include prospective cohort studies and randomised control trials.