Does NHANES underestimate true population-based exposures to pesticides? Exploring bias in NHANES human biomonitoring data.

总结/摘要 人体生物监测（HBM）-测量化学品，其反应产物或代谢产物， 生物样本-是一种暴露评估技术，通常被认为是暴露的“黄金标准”。 考核美国使用国家健康和营养检查调查（NHANES）作为工具， 为HBM国家项目收集样品。NHANES数据收集发生在移动的检查中 中心（MEC），大型拖车包含一个移动的实验室。为数据收集安排站点位置 包括考虑因素，如季节性天气模式和MEC单位运输的困难。因为 MEC单位不能轻易地穿越有冰雪修补的困难道路，后勤需要取样， 在经常遭受在较温暖的月份期间出现的严酷的冬季天气的地区（即，春季和夏季）， 可以在较冷的月份中对更温和的位置进行采样（即，冬季和秋季）。鉴于此，NHANES 可能随季节变化的数据可能会受到时间和空间偏差的影响。这种潜在的偏见，在 反过来，导致对人口接触和健康数据的不准确解释。我们将评估任何偏见， 来自NHANES的季节性化学品的HBM数据使用两个特定目标。1)开展州一级和季节性 NHANES周期中季节性和非季节性尿液化学生物标志物分布的评价 1999-2016年使用NCHS研究数据中心，允许访问受限的地理编码和采样日期。 2)将NHANES州一级尿液农药代谢物数据与小规模生物监测研究进行比较 在不同的季节在美国不同的州进行。这项研究可以提供信息， 疾病预防控制中心重新考虑他们的采样后勤，以更好地代表季节和区域变化，或将使我们能够 量化NHANES低估美国人口暴露的程度。

SUMMARY/ABSTRACT Human biomonitoring (HBM) – the measurement of a chemical, its reaction product, or metabolite in biosamples – is an exposure assessment technique that is often considered the “gold standard” in exposure assessment. The US uses the National Health and Nutrition Examination Survey (NHANES) as a vehicle for sample collection for its national HBM program. NHANES data collection occurs in Mobile Examination Centers (MEC), large trailers containing a mobile laboratory. Scheduling site locations for data collection includes considerations such as seasonal weather patterns and difficulties with MEC unit transit. Because MEC units cannot easily traverse difficult roadways with snow and ice patching, logistics require that sampling in areas often hit with harsh winter weather occur during the warmer months (i.e., spring and summer) whereas more temperate locations can be sampled in cooler months (i.e., winter and autumn). Given this, NHANES data that may vary by season could be subject to both temporal and spatial bias. This potential bias could, in turn, lead to inaccurate interpretations of population exposure and health data. We will evaluate any bias in HBM data of seasonal chemicals from NHANES using two specific aims. 1) Conduct state-level and seasonal evaluations of distributions of seasonal and non-seasonal chemical urinary biomarkers in NHANES Cycles 1999-2016 using the NCHS Research Data Center allowing access to restricted geocodes and sampling dates. 2) Compare NHANES state-level urinary pesticide metabolite data to smaller-scale biomonitoring studies conducted in different US states during different seasons. This study could provide information that will enable CDC to reconsider their sampling logistics to better represent seasonal and regional variations or will enable us to quantify the extent to which NHANES underestimates US population exposures.