Measuring serum melatonin in postmenopausal women: Implications for epidemiologic studies and breast cancer studies

作者：Chu Lisa W; John Esther M; Yang Baiyu; Kurian Allison W; Zia Yasaman; Yu Kai; Ingles Sue A; Stanczyk Frank Z; Hsing Ann W^*

来源：PLos One, 2018, 13(4): e0195666.

DOI：10.1371/journal.pone.0195666

Background
Circulating melatonin is a good candidate biomarker for studies of circadian rhythms and circadian disruption. However, epidemiologic studies on circulating melatonin are limited because melatonin is secreted at night, yet most epidemiologic studies collect blood during the day when melatonin levels are very low, and assays are lacking that are ultrasensitive to detect low levels of melatonin reliably.
Objective
To assess the performance of a refined radioimmunoassay in measuring morning melatonin among women.
Methods
We used morning serum samples from 47 postmenopausal women ages 48 +/- 80 years without a history of breast cancer who participated in the San Francisco Bay Area Breast Cancer Study, including 19 women who had duplicate measurements. The coefficient of variation (CV) and intraclass coefficient (ICC) were estimated using the random effect model.
Results
Reproducibility for the assay was satisfactory, with a CV of 11.2% and an ICC of 98.9%; correlation between the replicate samples was also high (R = 0.96). In the 47 women, serum melatonin levels ranged from 0.6 to 62.6 pg/ml, with a median of 7.0 pg/ml.
Conclusion
Our results suggest that it is possible to reliably measure melatonin in postmenopausal women in morning serum samples in large epidemiologic studies to evaluate the role of melatonin in cancer etiology or prognosis.

• 出版日期2018-4-11