Arsenic and Obesity: A Comparison of Urine Dilution Adjustment Methods.
Arsenic and Obesity: A Comparison of Urine Dilution Adjustment Methods.
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砷和肥胖症：尿液稀释调节方法的比较。
DOI：
10.1289/ehp1202
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发表时间：
2017-08-28
影响因子：
10.4
通讯作者：
Argos M
中科院分区：
文献类型：
--
作者：
Bulka CM;Mabila SL;Lash JP;Turyk ME;Argos M
在生物标志物分析中调整尿液稀释的常用方法是调整尿肌酐。然而，肌酐是肌肉质量的产物，因此与体重相关。在尿分析物和肥胖或肥胖相关结局的研究中，控制肌酐可能会导致碰撞分层偏倚。我们用尿砷的分析来说明这一现象。我们的目的是评估各种方法的调整尿稀释之间的关联尿砷浓度和肥胖的措施。利用国家健康和营养调查的数据，我们回归了体重指数（BMI）和腰围身高比对尿砷浓度的影响。我们比较了八种方法来解释尿液稀释，包括尿肌酐，渗透压和流速的标准化，并将这些指标作为独立的协变量。我们还使用了最近提出的称为协变量调整标准化的方法。以肌酐或渗透压作为标准化变量或协变量，观察到尿砷浓度与BMI和腰高比之间呈负相关。不调整稀释，标准化或调整尿流率，并使用协变量调整标准化导致砷浓度与BMI和腰围身高比之间的零关联。我们的研究结果表明，砷暴露与肥胖无关，尿肌酐和渗透压可能是砷暴露导致肥胖的因果途径上的碰撞者，作为水合作用和身体成分的共同后代。在尿生物标志物和肥胖或肥胖相关结局的研究中，应考虑替代指标，如尿流率或分析策略，如协变量调整标准化。https://doi.org/10.1289/EHP1202
A commonly used approach to adjust for urine dilution in analyses of biomarkers is to adjust for urinary creatinine. However, creatinine is a product of muscle mass and is therefore associated with body mass. In studies of urinary analytes and obesity or obesity-related outcomes, controlling for creatinine could induce collider stratification bias. We illustrate this phenomenon with an analysis of urinary arsenic. We aimed to evaluate various approaches of adjustment for urinary dilution on the associations between urinary arsenic concentration and measures of obesity. Using data from the National Health and Nutrition Examination Survey, we regressed body mass index (BMI) and waist-to-height ratios on urinary arsenic concentrations. We compared eight approaches to account for urine dilution, including standardization by urinary creatinine, osmolality, and flow rates, and inclusion of these metrics as independent covariates. We also used a recently proposed method known as covariate-adjusted standardization. Inverse associations between urinary arsenic concentration with BMI and waist-to-height ratio were observed when either creatinine or osmolality were used to standardize or as covariates. Not adjusting for dilution, standardizing or adjusting for urinary flow rate, and using covariate-adjusted standardization resulted in null associations observed between arsenic concentration in relation to BMI and waist-to-height ratio. Our findings suggest that arsenic exposure is not associated with obesity, and that urinary creatinine and osmolality may be colliders on the causal pathway from arsenic exposure to obesity, as common descendants of hydration and body composition. In studies of urinary biomarkers and obesity or obesity-related outcomes, alternative metrics such as urinary flow rate or analytic strategies such as covariate-adjusted standardization should be considered. https://doi.org/10.1289/EHP1202