Morning melatonin profiles are highly variable in preschool-aged children, limiting the reliable calculation of dim-light melatonin offset (DLMOff).
In a study of 20 healthy preschoolers (mean age 4.31 years, 45% female), evening melatonin profiles consistently allowed calculation of DLMO in all participants, but morning melatonin levels were highly variable, enabling DLMOff calculation in only 8 participants. Among those 8, later DLMOff was strongly associated with later chronotype (r=0.81), sleep offset (r=0.84), and midsleep (r=0.80).
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Morning melatonin profiles are highly variable in preschool-aged children, limiting the reliable calculation of dim-light melatonin offset (DLMOff). The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 34/100 (low).
The Claim
Morning melatonin profiles are highly variable in preschool-aged children, limiting the reliable calculation of dim-light melatonin offset (DLMOff).
This conclusion is most relevant to: Healthy preschool-aged children (mean age 4.31 ± 0.34 years, 45% female)..
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Variable Morning Melatonin Profiles Limit Determination of Dim-Light Melatonin Offset in Preschool-Aged Children. (Journal of biological rhythms, 2026) —
How It Works
The proposed biological pathway:
- ▸Children maintained a consistent sleep schedule for 7 days
- ▸Saliva samples collected in 20-30 min intervals in the morning and evening
- ▸Melatonin levels measured and compared to a 4 pg/ml threshold
- ▸Morning melatonin profiles were highly variable, limiting DLMOff calculation to only 40% of participants
Who Might Benefit
Evidence fit by population:
- ▸Healthy preschool-aged children (mean age 4.31 ± 0.34 years, 45% female).
Recommended Dose
N/A
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Small sample size (n=20) limits generalizability
- ▸DLMOff could only be calculated in 8 participants, reducing statistical power for morning phase analysis
Frequently Asked Questions
What is dim-light melatonin offset (DLMOff)?▼
DLMOff is the time in the morning when melatonin levels drop below a threshold (here 4 pg/ml), marking the end of the melatonin production period and serving as a marker of circadian phase.
Why was DLMOff difficult to measure in preschool children?▼
Morning melatonin levels were highly variable and often irregular, with 45% of children still having melatonin levels ≥4 pg/ml at habitual wake time, making it hard to determine a clear offset point.
How does DLMOff relate to sleep timing in children?▼
In the small subsample where DLMOff could be calculated, later DLMOff was strongly correlated with later chronotype (r=0.81), later sleep offset (r=0.84), and later midsleep (r=0.80).
What was the study design and duration?▼
This was an observational study where 20 healthy preschoolers maintained a consistent sleep schedule for 7 days, followed by a single in-home circadian assessment with saliva sampling.
References
- 1.Hartstein LE, Stowe SR, Wright KP, Diniz Behn C, LeBourgeois MK. “Variable Morning Melatonin Profiles Limit Determination of Dim-Light Melatonin Offset in Preschool-Aged Children..” Journal of biological rhythms, 2026. PMID: 42504584 DOI: 10.1177/07487304261469609