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Measuring Relative Insulin Secretion using a Co-Secreted Luciferase Surrogate
Published on: June 25, 2019
Reproducibility of serum leptin, insulin-like growth factor-I, and insulin-like growth factor-binding protein-3
Victoria M Chia1, Polly A Newcomb, Emily White
1Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, Wash. 98109, USA.
Background:
Many epidemiologic studies examine the effects of single measurements of hormones, including those related to obesity such as insulin-like growth factors (IGFs) or leptin, on disease associations; however, few studies have determined whether these single values accurately reflect measurements over time.
Methods:
We examined the reproducibility of hormones associated with obesity, specifically leptin, IGF-I, and IGF-binding protein-3 (IGFBP-3). Two fasting blood samples, approximately four months apart, were collected from 38 participants from the Seattle metropolitan area; leptin, IGF-I, and IGFBP-3 concentrations were measured in previously unthawed serum samples. Unadjusted and adjusted intraclass correlation coefficients (ICC) were calculated to assess reproducibility.
Results:
Adjusting for age and sex, the ICCs for leptin, IGF-I, and IGFBP-3 were 0.73, 0.83 and 0.60, respectively. Weighted kappas yielded similar results.
Conclusion:
These data suggest that for leptin, IGF-I, and IGFBP-3, a single fasting serum measurement can fairly reliably reflect the hormonal milieu over periods of months.