Background

Styrene is an established neurotoxicant at occupational levels, but effects at levels relevant to the general population have not been studied. We examined the neurologic effects of environmental styrene exposure among U.S. Gulf coast residents.

Methods

We used National Air Toxics Assessment (NATA) 2011 estimates of ambient styrene concentrations to assign exposure levels for 21,962 non-diabetic Gulf state residents, and additionally measured blood styrene concentration in a subset of participants (n = 874). Neurologic symptoms, as well as detailed covariate information, were ascertained via telephone interview. We used log-binomial regression to estimate prevalence ratios (PR) and 95% confidence intervals (95% CI) for cross-sectional associations between both ambient and blood styrene levels and self-reported neurologic symptoms. We estimated associations independently for ten unique symptoms, as well as for the presence of any neurologic, central nervous system (CNS), or peripheral nervous system (PNS) symptoms. We also examined heterogeneity of associations with estimated ambient styrene levels by race and sex.

Results

One-third of participants reported at least one neurologic symptom. The highest quartile of estimated ambient styrene was associated with one or more neurologic (PR, 1.12; 95% CI: 1.07,1.18), CNS (PR, 1.17; 95% CI: 1.11,1.25), and PNS (PR, 1.16; 95% CI: 1.09,1.25) symptom. Results were less consistent for biomarker analyses, but blood styrene level was suggestively associated with nausea (PR, 1.78; 95% CI: 1.04, 3.03). In stratified analyses, we observed the strongest effects among non-White participants.

Conclusions

Increasing estimated ambient styrene concentration was consistently associated with increased prevalence of neurologic symptoms. Associations between blood styrene levels and some neurologic symptoms were suggestive. Environmental styrene exposure levels may be sufficient to elicit symptomatic neurotoxic effects.

中文翻译：

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美国墨西哥湾沿岸居民的环境苯乙烯暴露和神经系统症状

背景

苯乙烯在职业水平上是公认的神经毒剂，但尚未研究与普通人群有关的水平的作用。我们检查了美国墨西哥湾沿岸居民中环境苯乙烯暴露的神经系统影响。

方法

我们使用美国国家空气毒性评估（NATA）2011年的环境苯乙烯浓度估算值，为21,962名非糖尿病海湾国家居民分配暴露水平，并另外测量了一部分参与者的血液中苯乙烯浓度（n = 874）。通过电话采访确定了神经系统症状以及详细的协变量信息。我们使用对数-二项式回归来估计环境和血液中苯乙烯水平与自我报告的神经系统症状之间的横断面联系的患病率（PR）和95％置信区间（95％CI）。我们针对十种独特症状以及任何神经系统，中枢神经系统的存在独立地估计了相关性（CNS）或周围神经系统（PNS）症状。我们还通过种族和性别检查了与环境苯乙烯水平估计值之间关联的异质性。

结果

三分之一的参与者报告了至少一种神经系统症状。估计的环境苯乙烯最高四分位数与一种或多种神经系统疾病（PR，1.12; 95％CI：1.07,1.18），CNS（PR，1.17; 95％CI：1.11,1.25）和PNS（PR，1.16; 95％CI：1.09,1.25）症状。生物标志物分析的结果不一致，但是血液苯乙烯水平暗示与恶心相关（PR，1.78； 95％CI：1.04，3.03）。在分层分析中，我们观察到了非白人参与者中最强的影响。

结论

估计周围苯乙烯浓度的增加与神经系统症状患病率的增加始终相关。血液中苯乙烯水平与某些神经系统症状之间的关联是暗示性的。环境苯乙烯暴露水平可能足以引起症状性神经毒性作用。