Pesticide Exposure And Neurologic Function In Farmworker

高水平农药接触后神经毒性的临床表现是众所周知的，但人们越来越担心农药也可能产生亚临床神经功能缺陷，特别是作为中毒事件的延迟后果或在长期、低水平接触的情况下。这些影响可能会降低个体的生活质量，或者是临床可检测到的功能障碍或明显神经系统疾病的前奏。很少有研究调查长期低剂量接触的神经学影响。与其他职业群体相比，农场工人可能高度接触农药，但他们的健康从未得到充分研究，部分原因是涉及后勤问题。我们研究了农药暴露和神经功能障碍之间的一组农场工人在中部佛罗里达，以解决农药神经毒性的科学问题，并调查在这个服务不足的群体农药的健康影响。这项研究的具体目的是：（一）确定长期职业性接触农药是否会损害使用一系列神经行为测试评估的感觉、运动或认知功能;以及（二）确定遗传易感性是否会改变农药的影响。 我们进行了一项横断面研究，比较农药暴露的农场工人和未暴露的对照。这项研究的参与者来自佛罗里达中部一个人口稳定的农场工人社区。这个社区的大多数农场工人从事三种类型的农业：种植和收获观赏蕨类植物，在苗圃工作，或采摘柑橘类水果。为了进入社区，我们与当地的倡导组织佛罗里达农场工人协会合作。我们将我们的目标人群定义为当地信用社的成员及其配偶;暴露的农场工人和未暴露的对照组都是从这一人群中招募的。我们筛选了80%的选定个体，其中81%的合格个体参与了研究。我们招募了288名曾经从事过至少一个月的农场工作的人（农场工人）和51名不符合这一标准的对照组。我们的研究在招募大样本方面是独一无二的，从定义的人群中获得了高应答率。 由于杀虫剂可能影响神经功能的许多方面，我们使用了一系列测试来评估感觉，运动和认知功能。在计算机上进行了一些测试。所使用的测试相对独立于教育和文化背景。我们收集了有关农业工作史、其他就业、人口统计学、生活方式和病史的信息，这些信息是由受过培训的人员亲自进行的结构化访谈。我们收集并存档了口腔细胞作为DNA的来源。遗传分析将集中在参与农药代谢的基因，如对氧磷酶。 在分析工作经历与神经行为表现之间的关系时，我们发现，曾经做过农活的人在四项测试中表现不佳--数字跨度、手指敲击、圣安娜和姿势摇摆--但对其他四项测试影响不大--符号数字潜伏期、振动触觉阈值、视觉对比敏感度和握力。受影响的测试评估认知和心理功能。与农场工作的关联在程度上与年龄和性别等个人特征的关联相似。较长的农场工作时间与较差的表现有关。协会与蕨类植物的工作比协会与苗圃或柑橘的工作更一致。赤字有关的工作经验的持续时间被认为是在前以及目前的农场工人，和性能下降与慢性接触，即使在没有农药中毒的历史。我们的结论是，长期的农场工作经验与可测量的认知和心理功能的缺陷。我们的研究扩展了以前的发现，在一项大型的、基于人群的研究中，比较了不同类型农业的工人，证明了与农场工作相关的神经功能缺损。这项研究的结果将有助于我们科学地了解农药暴露对神经功能的影响，并解决服务不足的少数群体的健康问题。

Clinical manifestations of neurotoxicity following high level pesticide exposure are well known, but there is growing concern that pesticides may also produce subclinical neurologic deficits, particularly as a delayed consequence of a poisoning episode or in situations of chronic, low-level exposure. Such effects might degrade an individual's quality of life or be a prelude to clinically detectable dysfunction or frank neurologic disease. Few studies have investigated the neurologic effects of chronic low-dose exposure. Farmworkers are likely to be highly exposed to pesticides, compared to other occupational groups, but their health has never been adequately studied, partly because of the logistical problems involved. We studied pesticide exposure and neurologic dysfunction among a group of farmworkers in central Florida in order to address the scientific issue of pesticide neurotoxicity and to investigate health effects of pesticides in this underserved group. The specific aims of the study were (i) to determine whether chronic occupational exposure to pesticides impairs sensory, motor or cognitive function evaluated using a battery of neurobehavioral tests; and (ii) to determine whether genetic susceptibility alters the effects of pesticides. We conducted a cross-sectional study comparing pesticide-exposed farmworkers to unexposed controls. Participants in the study came from a farmworker community in central Florida with a stable population. Most farmworkers in this community worked in one of three types of agriculture: growing and harvesting ornamental ferns, working in nurseries, or picking citrus fruit. To gain access to the community, we collaborated with the Farmworker Association of Florida, a local advocacy group. We defined our target population to be members of a local credit union and their spouses; both exposed farmworkers and unexposed controls were recruited from this population. We screened 80% of selected individuals, and 81% of those eligible participated in the study. We recruited 288 individuals who had ever done farm work for at least one month (farmworkers) and 51 controls who did not meet this criterion. Our study is unique in recruiting a large sample with a high response rate from a defined population. Since pesticides potentially affect many aspects of neurologic function, we used a battery of tests to evaluate sensory, motor, and cognitive function. Some tests were implemented on a computer. Tests used were relatively independent of education and cultural background. We collected information on history of farm work, other employment, demographics, lifestyle, and medical history in a structured interview administered in person by trained personnel. We collected and archived buccal cells to use as a source of DNA. Genetic analyses will focus on genes involved in pesticide metabolism, such as paraoxonase. In analyses of the relationship of work history to neurobehavioral performance, we found that ever having done farm work was associated with poor performance on four tests - digit span, finger tapping, Santa Ana, and postural sway - but had little effect on four others - symbol digit latency, vibrotactile threshold, visual contrast sensitivity, and grip strength. The affected tests evaluate cognitive and psychomotor function. Associations with farm work were similar in magnitude to associations with personal characteristics such as age and gender. Longer duration of farm work was associated with worse performance. Associations with fern work were more consistent than associations with nursery or citrus work. Deficits related to the duration of work experience were seen in former as well as current farmworkers, and decreased performance was related to chronic exposure even in the absence of a history of pesticide poisoning. We conclude that long-term experience of farm work is associated with measurable deficits in cognitive and psychomotor function. Our study extends previous findings by demonstrating farm work-related neurologic deficits in a large, population-based study that compared workers in different types of agriculture. The results of this study will contribute to our scientific understanding of the effects of pesticide exposure on neurologic function and also address the health problems of an underserved minority group.