Melatonin and health: an umbrella review of health outcomes and biological mechanisms of action.
Study Goal
The researchers aimed to evaluate the evidence from systematic and narrative reviews on the effects of melatonin (both endogenous and exogenous) on health and identify potential mechanisms of action.
Results Summary
The study found that melatonin was associated with a wide variety of health outcomes, with significant effects on sleep latency, pre-operative anxiety, agitation prevention, and breast cancer risk. However, most reviews were of low methodological quality, highlighting the need for more high-quality randomized clinical trials.
Population
Clinically and methodologically heterogeneous populations (not specified further).
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
melatonin (MLT) | neutral | health-related outcome measure | clinically and methodologically heterogeneous populations | - | effects on health | #1 |
melatonin (MLT) | neutral | a wide variety of health outcomes | clinically and methodologically heterogeneous populations | - | associated with | #2 |
melatonin (MLT) | decrease | sleep latency | - | P values less than 0.001 | significant | #3 |
melatonin (MLT) | decrease | pre-operative anxiety | - | P values less than 0.001 | significant | #4 |
melatonin (MLT) | neutral | prevention of agitation | - | P values less than 0.001 | significant | #5 |
melatonin (MLT) | decrease | risk of breast cancer | - | P values less than 0.001 | significant | #6 |
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.