Miller Mark D, Crofton Kevin M, Rice Deborah C, Zoeller R Thomas
Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, California 94612, USA.
Environ Health Perspect. 2009 Jul;117(7):1033-41. doi: 10.1289/ehp.0800247. Epub 2009 Feb 12.
There is increasing evidence in humans and in experimental animals for a relationship between exposure to specific environmental chemicals and perturbations in levels of critically important thyroid hormones (THs). Identification and proper interpretation of these relationships are required for accurate assessment of risk to public health.
We review the role of TH in nervous system development and specific outcomes in adults, the impact of xenobiotics on thyroid signaling, the relationship between adverse outcomes of thyroid disruption and upstream causal biomarkers, and the societal implications of perturbations in thyroid signaling by xenobiotic chemicals.
We drew on an extensive body of epidemiologic, toxicologic, and mechanistic studies.
THs are critical for normal nervous system development, and decreased maternal TH levels are associated with adverse neuropsychological development in children. In adult humans, increased thyroid-stimulating hormone is associated with increased blood pressure and poorer blood lipid profiles, both risk factors for cardiovascular disease and death. These effects of thyroid suppression are observed even within the "normal" range for the population. Environmental chemicals may affect thyroid homeostasis by a number of mechanisms, and multiple chemicals have been identified that interfere with thyroid function by each of the identified mechanisms.
Individuals are potentially vulnerable to adverse effects as a consequence of exposure to thyroid-disrupting chemicals. Any degree of thyroid disruption that affects TH levels on a population basis should be considered a biomarker of adverse outcomes, which may have important societal outcomes.
在人类和实验动物中，越来越多的证据表明，接触特定环境化学物质与至关重要的甲状腺激素（THs）水平紊乱之间存在关联。准确评估对公众健康的风险需要识别并正确解读这些关系。
我们综述了甲状腺激素在神经系统发育中的作用以及对成年人的特定影响、外源性物质对甲状腺信号传导的影响、甲状腺功能紊乱的不良后果与上游因果生物标志物之间的关系，以及外源性化学物质对甲状腺信号传导的干扰所产生的社会影响。
我们借鉴了大量的流行病学、毒理学和机制研究。
甲状腺激素对正常神经系统发育至关重要，母亲甲状腺激素水平降低与儿童不良神经心理发育有关。在成年人类中，促甲状腺激素升高与血压升高和血脂状况较差有关，这两者都是心血管疾病和死亡的危险因素。即使在人群的“正常”范围内，也能观察到甲状腺抑制的这些影响。环境化学物质可能通过多种机制影响甲状腺稳态，并且已经确定多种化学物质可通过每种已确定的机制干扰甲状腺功能。
个体可能因接触甲状腺干扰化学物质而容易受到不良影响。任何程度的甲状腺功能紊乱，只要在人群层面上影响甲状腺激素水平，都应被视为不良后果的生物标志物，这可能会产生重要的社会影响。
