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Related Experiment Video

Updated: Jun 14, 2026

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

Published on: April 7, 2020

Measuring serum melatonin in epidemiologic studies.

Ann W Hsing¹, Tamra E Meyer, Shelley Niwa

¹Division of Cancer Epidemiology and Genetics, National Cancer Institute, 6120 Executive Boulevard, EPS 5024, MSC 7234, Bethesda, MD 20852-7234, USA. hsinga@mail.nih.gov

Cancer Epidemiology, Biomarkers & Prevention : a Publication of the American Association for Cancer Research, Cosponsored by the American Society of Preventive Oncology

|March 25, 2010

Summary

This summary is machine-generated.

This study refined melatonin assays, showing reliable detection in serum for epidemiologic research. Improved methods enable investigating circadian rhythms and cancer risk.

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Area of Science:

Biochemistry
Epidemiology
Chronobiology

Background:

Epidemiologic data on serum melatonin and cancer is limited due to a lack of sensitive assays for daylight-collected samples.
Circadian rhythm disruption is a growing area of interest in cancer etiology.

Purpose of the Study:

To assess the reproducibility and refine a melatonin radioimmunoassay (RIA).
To evaluate the application of improved melatonin assays in epidemiologic studies.
To characterize melatonin levels in serum, urine, and plasma across different ethnic groups.

Main Methods:

Assessed reproducibility of standard and refined melatonin RIA assays using serum and urine.
Collected serum, urine, and plasma samples from 135 men of diverse ethnic backgrounds.
Correlated serum melatonin with urinary 6-sulfatoxymelatonin and compared serum-plasma melatonin levels.

Main Results:

High reproducibility was achieved for both standard and refined serum assays, and urine-based assays.
A positive correlation was observed between morning serum melatonin and 24-hour urinary 6-sulfatoxymelatonin.
Serum and plasma melatonin levels showed a strong correlation; morning serum melatonin was significantly higher than afternoon levels.
Melatonin levels varied by ethnicity, with Chinese men exhibiting lower levels compared to Caucasian, African-American, and Ghanaian men.

Conclusions:

Melatonin can be reliably detected in serum samples collected during epidemiologic studies across various racial groups.
Improved melatonin assays facilitate the investigation of the circadian rhythm hypothesis in cancer etiology.
These findings support the use of refined melatonin assays in future cancer epidemiology research.