The Maximum Cumulative Ratio (MCR) quantifies the degree to which a single chemical drives the cumulative risk of an individual exposed to multiple chemicals. Phthalates are a class of chemicals with ubiquitous exposures in the general population that have the potential to cause adverse health effects in humans. This work used the MCR to evaluate coexposures to six phthalates as measured in biomonitoring data from the most recent cycle (2013–2014) of the National Health and Nutrition Examination Survey (NHANES). The values of MCR, Hazard Index (HI), and phthalate-specific Hazard Quotients (HQs) were determined for 2663 NHANES participants aged six years and older by using reverse dosimetry techniques to calculate steady-state doses consistent with concentrations of metabolites of six phthalates in urine and using Tolerable Daily Intake values. There were 21 participants (0.8% of the NHANES sample) with HI > 1. Of those, 43% (9/21) would have been missed by chemical-by-chemical assessments (i.e. all HQs were less than one). The mean MCR value in the 21 participants was 2.1. HI and MCR values were negatively correlated (p < 0.001) indicating that most participants, especially those with elevated HI values, had their cumulative risks driven by relatively large doses of a single phthalate rather than doses of multiple phthalates. The dominate phthalate varied across participants. Children (aged 6–17 years) had a higher HI values (p < 0.01) than adults (18 + years). However, the probability of having HI > 1 was not driven by age, gender, or ethnicity. The cumulative exposures of concern largely originated from a subset of three of the fifteen possible pairs of the six phthalates. These findings suggest that cumulative exposures were a potential concern for a small portion of the surveyed participants involving a subset of the phthalates explored. The largest risks tended to occur in individuals whose exposures were dominated by a single phthalate.

最大累积比率（MCR）量化了一种化学物质驱使个体接触多种化学物质的累积风险的程度。邻苯二甲酸盐是一类在普通人群中普遍接触的化学物质，有可能对人类造成不利的健康影响。这项工作使用MCR评估了六种邻苯二甲酸酯的共同暴露，这是根据国家健康与营养检查调查（NHANES）的最新周期（2013-2014）的生物监测数据测得的。通过使用反向剂量测定技术计算与六种邻苯二甲酸酯代谢物浓度一致的稳态剂量，确定了6663岁及以上的2663名NHANES参与者的MCR，危害指数（HI）和邻苯二甲酸酯特异性危害商（HQs）的值。尿液中，并使用可耐受的每日摄入量值。HI> 1的受试者为21名（占NHANES样本的0.8％），其中43％（9/21）被逐项化学评估遗漏了（即所有HQ均小于1）。21名参与者的平均MCR值为2.1。HI和MCR值呈负相关（p  <0.001）表明大多数参与者，尤其是那些HI值升高的参与者，其累积风险是由相对较大剂量的单种邻苯二甲酸盐而不是多剂量的邻苯二甲酸盐驱动的。邻苯二甲酸盐占主导地位因参与者而异。儿童（6-17岁）的HI值较高（p <0.01）比成人（18岁以上）高。但是，HI> 1的可能性不受年龄，性别或种族的影响。所关注的累积暴露量主要来自六种邻苯二甲酸盐的十五对可能的三对中的一部分。这些发现表明，累积的接触量是涉及被调查邻苯二甲酸盐子集的一小部分被调查参与者的潜在担忧。最大的风险往往发生在暴露于单一邻苯二甲酸盐的个体中。