Paediatric use of melatonin: Letter to the Editor regarding the manuscript "Current role of melatonin in pediatric neurology:Clinical recommendations" by Bruni et al. Eur J Paediatr Neurol. 2015 Mar;19(2):122-33

Plant-derived melatonin from food: a gift of nature

In recent years, people have become increasingly interested in bioactive ingredients from plants, especially antioxidant molecules such as melatonin, which are beneficial to human health. The purpose of this article is to provide new information on plant-derived foods with a high content of melatonin. We comprehensively summarize the content of melatonin in plant-derived foods and discuss the factors that influence melatonin levels to provide new ideas on enhancement. Additionally, we describe the biosynthetic pathway of melatonin and identify its major functions. Medicinal herbs are often rich in melatonin while many vegetables and fruits exhibit somewhat lower levels with wide variations among species. The genetic traits of plants, the phenological stage of the cultivar, the photoperiod, the level of stress to which the plants are exposed at the time of harvest, exposure to agrochemicals and determination methods are the main factors affecting the melatonin content. To date, standardization of uniform sampling times and the use of suitable pretreatments as well as determination methods have not been achieved. The results of the studies reviewed highlight the potentially important role of plant melatonin in influencing the progression of human diseases. Based on the health promotional aspects of melatonin, consuming foods containing higher concentrations of tryptophan and melatonin is suggested.

Association Between Disturbed Sleep and Depression in Children and Youths: A Systematic Review and Meta-analysis of Cohort Studies

IMPORTANCE

Disturbed sleep represents a potentially modifiable risk factor for depression in children and youths that can be targeted in prevention programs.

OBJECTIVE

To evaluate the association between disturbed sleep and depression in children and youths using meta-analytic methods.

DATA SOURCES

Embase, MEDLINE, PsycINFO, Scopus, Web of Science, and ProQuest Dissertations & Theses Global were searched for articles published from 1980 to August 2019.

STUDY SELECTION

Prospective cohort studies reporting estimates, adjusted for baseline depression, of the association between disturbed sleep and depression in 5- to 24-year-old participants from community and clinical-based samples with any comorbid diagnosis. Case series and reports, systematic reviews, meta-analyses, and treatment, theoretical, and position studies were excluded. A total of 8700 studies met the selection criteria. This study adhered to the guidelines of the Preferred Reporting Items for Systematic Reviews (PRISMA) and Meta-analyses and the Meta-analysis of Observational Studies in Epidemiology (MOOSE) statements.

DATA EXTRACTION AND SYNTHESIS

Study screening and data extraction were conducted by 2 authors at all stages. To pool effect estimates, a fixed-effect model was used if I2 < 50%; otherwise, a random-effects model was used. The I2 statistic was used to assess heterogeneity. The risk of bias was assessed using the Research Triangle Institute Item Bank tool. Metaregression analyses were used to explore the heterogeneity associated with type of ascertainment, type of and assessment tool for disturbed sleep and depression, follow-up duration, disturbed sleep at follow-up, and age at baseline.

MAIN OUTCOME AND MEASURES

Disturbed sleep included sleep disturbances or insomnia. Depression included depressive disorders or dimensional constructs of depression. Covariates included age, sex, and sociodemographic variables.

RESULTS

A total of 22 studies (including 28 895 patients) were included in the study, of which 16 (including 27 073 patients) were included in the meta-analysis. The pooled β coefficient of the association between disturbed sleep and depression was 0.11 (95% CI, 0.06-0.15; P < .001; n = 14 067; I2 = 50.8%), and the pooled odds ratio of depression in those with vs without disturbed sleep was 1.50 (95% CI, 1.13-2.00; P = .005; n = 13 006; I2 = 87.7%). Metaregression and sensitivity analyses showed no evidence that pooled estimates differed across any covariate. Substantial publication bias was found.

CONCLUSIONS AND RELEVANCE

This meta-analysis found a small but statistically significant effect size indicating an association between sleep disruption and depressive symptoms in children and youths. The high prevalence of disturbed sleep implies a large cohort of vulnerable children and youths who could develop depression. Disrupted sleep should be included in multifaceted prevention programs starting in childhood.

Do insomnia and/or sleep disturbances predict the onset, relapse or worsening of depression in community and clinical samples of children and youth? Protocol for a systematic review and meta-analysis

INTRODUCTION

Disturbed sleep represents a potentially important modifiable risk factor for the development of depression in children and youth. This protocol for a systematic review proposes to investigate whether insomnia and/or sleep disturbances predict child and youth depression in community and clinical-based samples.

METHODS AND ANALYSIS

The protocol adheres to the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. English-written, longitudinal studies that quantitatively estimated the prediction of depression by insomnia and/or sleep disturbances in individuals 5-24 years of age will be included. EMBASE, MEDLINE, PsychINFO, Scopus and Web of Science and grey literature will be searched from 1980 to the present. For the selection of studies, two reviewers will be involved. Data extraction will be conducted by one author and checked independently by a second author. Risk of bias will be appraised using the Research Triangle Institute Item Bank tool. Heterogeneity will be measured using the I2 statistics. Meta-analysis will be carried out if ≥3 results are available and if outcome measures can be pooled. The choice between a random-effect or fixed-effect model will be based both on the I2 statistics and the participant and study characteristics of the combined studies. Results of the meta-analyses will be summarised by a forest plot. Analyses will be performed in subgroups stratified by key variables defined depending on the amount and type of information retrieved.A narrative synthesis will be conducted in place of the meta-analysis should the pooling of data not be possible. Quality of evidence will be rated using the Grading of Recommendations Assessment, Development and Evaluation guidelines.As this is a protocol for systematic review and meta-analysis of published data, ethics review and approval are not required. The findings will be published in a peer-reviewed journal and disseminated at scientific conferences and in patient advocacy organisations.

PROSPERO REGISTRATION NUMBER

CRD42019136729.