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Comparison of strategies to efficiently combine repeated urine samples in biomarker-based studies

Abstract : Background: In biomarker-based studies, collecting repeated biospecimens per participant can decrease measurement error, particularly for biomarkers displaying high within-subject variability. Guidelines to combine such repeated biospecimens do not exist. Aims: To compare the efficiency of several designs relying on repeated biospecimens to estimate exposure over 7 days. Methods: We quantified triclosan and bisphenol A (BPA) in all urine voids (N = 427) collected over seven days from eight individuals. We estimated the volume-weighted concentrations for all urine samples collected during a week and compared these gold standards with the concentrations obtained for equal-volume pools (standardized or not for urine dilution), unequal-volume pools (based on sample volume or creatinine concentration), and for the mean of the creatinine-standardized concentrations measured in each spot sample. Results: For both chemicals, correlations with gold standards were similar for equal- and unequal-volume pooling designs. Only for BPA, correlation coefficients were markedly lower after standardization for specific gravity or creatinine of concentrations estimated in equal-volume pools. Averaging BPA creatinine-standardized concentrations measured in each spot sample led also to lower correlations with gold standards compared to those obtained for unstandardized pooling designs. Conclusion: For BPA and triclosan, considering individual urine sample volume or creatinine concentrations when pooling is unnecessary because equal-volume pool adequately estimates concentrations in gold standards. Standardization for specific gravity or creatinine of the concentrations assessed in equal-volume pool as well as averaging creatinine-standardized concentrations measured in each individual spot sample are not suitable for BPA. These results provide a practical framework on how to combine repeated biospecimens in epidemiological studies.
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https://www.hal.inserm.fr/inserm-03269506
Contributor : Maïlys Barbagallo <>
Submitted on : Thursday, June 24, 2021 - 10:05:06 AM
Last modification on : Wednesday, July 7, 2021 - 2:07:19 PM

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Claire Philippat, Antonia Calafat. Comparison of strategies to efficiently combine repeated urine samples in biomarker-based studies. Environmental Research, Elsevier, 2021, 192, pp.110275. ⟨10.1016/j.envres.2020.110275⟩. ⟨inserm-03269506⟩

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