Hoet Perrine, Deumer Gladys, Bernard Alfred, Lison Dominique, Haufroid Vincent
Louvain centre for Toxicology and Applied Pharmacology (LTAP), Institut de Recherche Expérimentale et Clinique (IREC), Université catholique de Louvain, Brussels, Belgium.
Department of clinical chemistry, Cliniques Universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium.
J Expo Sci Environ Epidemiol. 2016 May-Jun;26(3):296-302. doi: 10.1038/jes.2015.23. Epub 2015 Apr 1.
Systematic creatinine adjustment of urinary concentrations of biomarkers has been a challenge over the past years because the assumption of a constant creatinine excretion rate appears erroneous and the issue of overadjustment has recently emerged. This study aimed at determining whether systematic creatinine adjustment is to be recommended for urinary concentrations of trace elements (TEs) in environmental settings. Paired 24-h collection and random spot urine samples (spotU) were obtained from 39 volunteers not occupationally exposed to TEs. Four models to express TEs concentration in spotU were tested to predict the 24-h excretion rate of these TEs (TEμg/24h) considered as the gold standard reference: absolute concentration (TEμg/l); ratio to creatinine (TEμg/gcr); TEμg/gcr adjusted to creatinine (TEμg/gcr-adj); and concentration adjusted to specific gravity (TEμg/l-SG). As, Ba, Cd, Co, Cr, Cu, Hg, Li, Mo, Ni, Pb, Sn, Sb, Se, Te, V and Zn were analyzed by inductively coupled argon plasma mass spectrometry. There was no single pattern of relationship between urinary TEs concentrations in spotU and TEμg/24h. TEμg/l predicted TEμg/24h with an explained variance ranging from 0 to 60%. Creatinine adjustment improved the explained variance by an additional 5 to ~60% for many TEs, but with a risk of overadjustment for the most of them. This issue could be addressed by adjusting TE concentrations on the basis of the regression coefficient of the relationship between TEμg/gcr and creatinine concentration. SG adjustment was as suitable as creatinine adjustment to predict TEμg/24h with no SG-overadjustment (except V). Regarding Cd, Cr, Cu, Ni and Te, none of the models were found to reflect TEμg/24h. In the context of environmental exposure, systematic creatinine adjustment is not recommended for urinary concentrations of TEs. SG adjustment appears to be a more reliable alternative. For some TEs, however, neither methods appear suitable.
在过去几年中，对尿中生物标志物浓度进行系统性肌酐校正一直是一项挑战，因为假定肌酐排泄率恒定似乎是错误的，而且最近出现了过度校正的问题。本研究旨在确定在环境背景下，对于尿中微量元素（TEs）浓度是否应推荐进行系统性肌酐校正。从39名未职业接触TEs的志愿者中采集了配对的24小时尿液样本和随机即时尿样（spotU）。测试了四种表达spotU中TEs浓度的模型，以预测这些TEs的24小时排泄率（TEμg/24h），将其视为金标准参考：绝对浓度（TEμg/l）；与肌酐的比值（TEμg/gcr）；根据肌酐校正的TEμg/gcr（TEμg/gcr-adj）；以及根据比重校正的浓度（TEμg/l-SG）。采用电感耦合氩等离子体质谱法分析了砷、钡、镉、钴、铬、铜、汞、锂、钼、镍、铅、锡、锑、硒、碲、钒和锌。spotU中尿TEs浓度与TEμg/24h之间不存在单一的关系模式。TEμg/l预测TEμg/24h的可解释方差范围为0至60%。对于许多TEs，肌酐校正使可解释方差额外提高了5%至约60%，但大多数TEs存在过度校正的风险。这个问题可以通过根据TEμg/gcr与肌酐浓度之间关系的回归系数来调整TE浓度来解决。比重校正与肌酐校正一样适合预测TEμg/24h，且不存在比重过度校正（除钒外）。对于镉、铬、铜、镍和碲，未发现任何模型能反映TEμg/24h。在环境暴露的背景下，不建议对尿中TEs浓度进行系统性肌酐校正。比重校正似乎是一种更可靠的替代方法。然而，对于某些TEs，两种方法似乎都不合适。
