1 Epidemiology Branch , National Institute of Environmental Health Sciences, National Institutes of Health , Research Triangle Park, North Carolina.
2 Epidemiology Department, University of North Carolina Gillings School of Global Public Health , Chapel Hill, North Carolina.
Environ Health Perspect. 2019 Apr;127(4):47006. doi: 10.1289/EHP3954.
Although styrene is an established neurotoxicant at occupational exposure levels, its neurotoxicity has not been characterized in relation to general population exposures. Further, occupational research to date has focused on central nervous system impairment.
We assessed styrene-associated differences in sensory and motor function among Gulf coast residents.
We used 2011 National Air Toxics Assessment estimates of ambient styrene to determine exposure levels for 2,956 nondiabetic Gulf state residents enrolled in the Gulf Long-term Follow-up Study, and additionally measured blood styrene concentration in a subset of participants 1 to 2 y after enrollment ([Formula: see text]). Participants completed an enrollment telephone interview and a comprehensive test battery to assess sensory and motor function during a clinical follow-up exam 2 to 4 y later. Detailed covariate information was ascertained at enrollment via telephone interview. We used multivariate linear regression to estimate continuous differences in sensory and motor function, and log-binomial regression to estimate prevalence ratios for dichotomous outcomes. We estimated associations of both ambient and blood styrene exposures with sensory and motor function, independently for five unique tests.
Those participants in the highest 25% vs. lowest 75% of ambient exposure and those in the highest 10% vs. lowest 90% of blood styrene had slightly diminished visual contrast sensitivity. Mean vibrotactile thresholds were lower among those in the highest vs. lowest quartile of ambient styrene and the highest 10% vs. lowest 90% of blood styrene ([Formula: see text] log microns; 95% CI: [Formula: see text], [Formula: see text] and [Formula: see text] log microns; 95% CI: [Formula: see text], [Formula: see text], respectively). The highest vs. lowest quartile of ambient styrene was associated with significantly poorer postural stability, and (unexpectedly) with significantly greater grip strength.
We observed associations between higher styrene exposure and poorer visual, sensory, and vestibular function, though we did not detect associations with reduced voluntary motor system performance. Associations were more consistent for ambient exposures, but we also found notable associations with measured blood styrene. https://doi.org/10.1289/EHP3954.
尽管苯乙烯在职业暴露水平下是一种已确立的神经毒物，但尚未对其在一般人群暴露中的神经毒性进行特征描述。此外，迄今为止的职业研究集中于中枢神经系统损伤。
我们评估了墨西哥湾沿岸居民中与苯乙烯相关的感觉和运动功能差异。
我们使用 2011 年国家空气毒物评估对环境苯乙烯的估计值，确定了参加海湾长期随访研究的 2956 名非糖尿病墨西哥湾州居民的暴露水平，并在参与者入组后 1 至 2 年内另外测量了血液中苯乙烯的浓度([Formula: see text])。参与者在临床随访检查期间完成了入组电话访谈和综合测试套件，以评估感觉和运动功能，该检查在入组后 2 至 4 年内进行。通过电话访谈在入组时详细确定了详细的协变量信息。我们使用多元线性回归来估计感觉和运动功能的连续差异，并使用对数二项式回归来估计二项式结果的患病率比。我们分别独立地对五个独特的测试评估了环境和血液苯乙烯暴露与感觉和运动功能的关联。
与最低 75%的环境暴露相比，处于最高 25%的环境暴露和最高 10%的血液苯乙烯暴露的参与者的视觉对比敏感度略有降低。与环境苯乙烯的最高四分位与最低四分位相比，与血液苯乙烯的最高 10%与最低 90%相比，平均振动觉阈值更低([Formula: see text]log 微米；95%CI：[Formula: see text]，[Formula: see text]和[Formula: see text]log 微米；95%CI：[Formula: see text]，[Formula: see text]）。与环境苯乙烯的最高四分位相比，与最低四分位相比，位置稳定性明显较差，（出乎意料地）握力明显更大。
我们观察到较高的苯乙烯暴露与视觉、感觉和前庭功能下降之间存在关联，但我们没有发现与自主运动系统功能下降有关的关联。环境暴露的相关性更为一致，但我们也发现与血液中测量的苯乙烯有明显的关联。https://doi.org/10.1289/EHP3954。
