Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action
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Author(s)
Type
Journal Article
Abstract
Background: Our aims were to evaluate critically the evidence from systematic reviews as well as narrative reviews
of the effects of melatonin (MLT) on health and to identify the potential mechanisms of action involved.
Methods: An umbrella review of the evidence across systematic reviews and narrative reviews of endogenous and
exogenous (supplementation) MLT was undertaken. The Oxman checklist for assessing the methodological quality
of the included systematic reviews was utilised. The following databases were searched: MEDLINE, EMBASE, Web of
Science, CENTRAL, PsycINFO and CINAHL. In addition, reference lists were screened. We included reviews of the
effects of MLT on any type of health-related outcome measure.
Results: Altogether, 195 reviews met the inclusion criteria. Most were of low methodological quality (mean -4.5,
standard deviation 6.7). Of those, 164 did not pool the data and were synthesised narratively (qualitatively) whereas
the remaining 31 used meta-analytic techniques and were synthesised quantitatively. Seven meta-analyses were
significant with P values less than 0.001 under the random-effects model. These pertained to sleep latency,
pre-operative anxiety, prevention of agitation and risk of breast cancer.
Conclusions: There is an abundance of reviews evaluating the effects of exogenous and endogenous MLT on
health. In general, MLT has been shown to be associated with a wide variety of health outcomes in clinically and
methodologically heterogeneous populations. Many reviews stressed the need for more high-quality randomised
clinical trials to reduce the existing uncertainties.
of the effects of melatonin (MLT) on health and to identify the potential mechanisms of action involved.
Methods: An umbrella review of the evidence across systematic reviews and narrative reviews of endogenous and
exogenous (supplementation) MLT was undertaken. The Oxman checklist for assessing the methodological quality
of the included systematic reviews was utilised. The following databases were searched: MEDLINE, EMBASE, Web of
Science, CENTRAL, PsycINFO and CINAHL. In addition, reference lists were screened. We included reviews of the
effects of MLT on any type of health-related outcome measure.
Results: Altogether, 195 reviews met the inclusion criteria. Most were of low methodological quality (mean -4.5,
standard deviation 6.7). Of those, 164 did not pool the data and were synthesised narratively (qualitatively) whereas
the remaining 31 used meta-analytic techniques and were synthesised quantitatively. Seven meta-analyses were
significant with P values less than 0.001 under the random-effects model. These pertained to sleep latency,
pre-operative anxiety, prevention of agitation and risk of breast cancer.
Conclusions: There is an abundance of reviews evaluating the effects of exogenous and endogenous MLT on
health. In general, MLT has been shown to be associated with a wide variety of health outcomes in clinically and
methodologically heterogeneous populations. Many reviews stressed the need for more high-quality randomised
clinical trials to reduce the existing uncertainties.
Date Issued
2018-02-05
Date Acceptance
2017-12-20
Citation
BMC Medicine, 2018, 16
ISSN
1741-7015
Publisher
BioMed Central
Journal / Book Title
BMC Medicine
Volume
16
Copyright Statement
© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver
(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
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Subjects
11 Medical And Health Sciences
General & Internal Medicine
Publication Status
Published
Article Number
18