The dim light melatonin onset across ages, methodologies, and sex and its relationship with morningness/eveningness

Abstract

The onset of melatonin secretion, the Dim Light Melatonin Onset or DLMO is a tool for determining the phase of the circadian timing system. While small studies have investigated the impacts of age and methods of calculating DLMO, there is no DLMO reference range. In the current study, the saliva DLMO from 121 published studies (3579 subjects) and plasma DLMO in 31 studies (818 subjects) in healthy control subjects (3 - 73 years) were analysed. In a subset of 53 papers (1749 subjects) individual saliva DLMO and MEQ scores were obtained from authors or mined from publications and a reference range was constructed. Saliva DLMO was earliest in children to 10 years of age and latest around 20 years of age and thereafter advanced with age by 30 minutes in the oldest subjects. Melatonin assay methods and DLMO calculation methods had little effect on the determination of the DLMO. Saliva DLMO was correlated (P < 0.001) with the MEQ score; lower MEQ scores were associated with later DLMO. MEQ scores increased with age, reflecting a tendency towards Morningness. An evaluation of 14 saliva DLMO studies of clinically diagnosed DSWPD patients (mean ages 20 to 31 years) revealed mean saliva DLMO within the reference range albeit at the late extreme. Peak plasma melatonin levels from 179 studies of healthy subjects revealed a high degree of variability within studies and age groups, but only a small decline between the 20 and 50 years and lowest levels after 70 years.

Do sleep and circadian characteristics predict alcohol use in adult drinkers?

“…While plausible, this explanation seems at odds with the findings in a recent paper based on longitudinal data , which stratified the dataset by age. In the subsample of It is also plausible that a lower degree of circadian misalignment is present in the current sample given that the tendency toward late sleep/circadian timing diminishes over time after peaking around age 20 (Kennaway, 2023;Roenneberg et al, 2004) and that adults tend to have a larger degree of control over their work schedules. Thus, circadian factors may be less relevant to the general adult milieu, and correspondingly less relevant to their alcohol use.…”

Neuropsychiatric disorders, chronotype and sleep: A narrative review of GWAS findings and the application of Mendelian randomization to investigate causal relationships

“…Currently, the sleep phenotype with the most power is chronotype. The genetic factor of chronotype allows MR analysis to be performed using this phenotype however given that chronotype is self-reported, it is not an ideal assessment of circadian rhythm alterations and further studies may integrate data on measurements such as dim-light melatonin onset, 62 which give a more accurate representation of the impact of sleep and circadian rhythm alterations on neuropsychiatric disorder risk. 61 Some areas of concern in the included MR analyses include the decision in some published studies to lower the p-value threshold for IVs, which could potentially void the relevance assumption.…”

Delayed sleep wake phase disorder in adolescents: an updated review

“…A primary urinary metabolite of melatonin, 6-sulphatoxymelatonin (aMT6s), can be collected every 2–8 h over a 24–48-h period, but typically saliva is easier [38]. According to one study, saliva samples should be taken every 30 to 60 min under dim light (<30 lx) for at least 1 h prior to and throughout the expected rise in melatonin [39 ▪ ]. However, a major obstacle towards using this as a standard circadian phase marker is the monetary expense of the melatonin assay, as well as the time expense of obtaining the samples [36].…”