Project - Influences of endogenous and exogenous melatonin in older adults at risk dementia
Mild cognitive impairment, dementia
Research Project Description
My PhD examines predictors of endogenous circadian phase (as assessed by Dim Light Melatonin Onset), which is bidirectionally linked to dementia development, and the effect of exogenous melatonin on brain oxidative stress, blood pressure, blood biomarkers, mood and sleep in older adults at risk of dementia.
Study 1 – Systematic Review and Meta-analysis
The aim of my systematic review and meta-analysis was to investigate the safety of melatonin supplementation in randomised controlled trials with melatonin doses above 10mg in human adults over 30 years of age. Out of over 1000 abstracts, 79 papers were analysed.
Study 2 – Retrospective analysis
Study 2 is a retrospective analysis to create a multiple linear regression of predictors of Dim-Light Melatonin Onset as well as an exploratory analysis to find correlates of phase angle of entrainment, the difference between DLMO and an external variable such as habitual sleep time, and see how these differ between controls and individuals at risk of dementia. Correlates include sleep-wake variables, light exposure at different times of the day and demographic variables.
Study 3 – Randomised Controlled Trial
I am conducting a 12-week randomised placebo-controlled double-blind trial of 25mg of melatonin in individuals with Mild Cognitive Impairment (MCI). The primary outcomes are feasibility, acceptability and tolerability. Secondary outcomes include the effect of melatonin on brain oxidative stress, blood pressure (including pulse wave velocity and analysis), blood biomarkers, mood, cognition, and sleep. This is the first study of high-dose melatonin in older adults with MCI.
Key Publications from this project
Menczel Schrire Z, Phillips CL, Duffy SL, Marshall NS, Mowszowski L, La Monica HM, Gordon CJ, Chapman JL, Saini B, Lewis SJG, Naismith SL, Grunstein RR, Hoyos CM. Feasibility of 3-month melatonin supplementation for brain oxidative stress and sleep in mild cognitive impairment: protocol for a randomised, placebo-controlled study. BMJ Open. 2021 Feb 10;11(2):e041500. doi: 10.1136/bmjopen-2020-041500. PMID: 33568368; PMCID: PMC7878132.