BACKGROUND Lipophilic compounds such as polychlorinated biphenyls (PCBs) are primarily stored in adipose tissue, but exercise-induced lipolysis is able to release PCBs from the adipose tissue into the circulation. The plasma concentration, distribution and metabolism of PCBs can thus vary much among individuals due to inter-human variations in lifestyle behavior and pharmacokinetics. OBJECTIVES We examined the observational relationship of circulating plasma PCB concentrations with cardiorespiratory fitness, engagement in vigorous physical activity and fat mass in a healthy Danish child population. METHODS Data on ∑PCB (PCB138, PCB153 and PCB180), cardiorespiratory fitness, skinfold thickness and objectively measured physical activity of 509 children derived from the Danish sub-study of The European Youth Heart Study. RESULTS Higher fitness and greater leanness were associated with elevated plasma ∑PCB in both boys and girls. The associations were independent of each other and persisted after controlling for socio-economic status and duration of breastfeeding. We observed an almost three-fold increase in plasma ∑PCB level in the most fit/least fat children relative to the least fit/most fat children. The association between fatness and ∑PCB was strongest for boys as girls, and especially pubertal girls, displayed lower decrease in plasma ∑PCB with higher fat mass. DISCUSSION Our findings suggest that increased lipolysis stimulates the release of PCBs into the vasculature. The consequence is higher plasma levels of PCB in very fit and lean subjects. This scenario is likely to cause negative confounding in epidemiological observations of PCB and cardio-metabolic health. At the same time adipose tissue may play a dual role in promoting adverse health and providing a relatively safe place to store PCB.

中文翻译：

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适合健康和瘦弱儿童的高循环血浆多氯联苯（PCB）：欧洲青年心脏研究。

背景技术诸如多氯联苯（PCB）的亲脂性化合物主要存储在脂肪组织中，但是运动诱导的脂解能够将PCB从脂肪组织释放到循环中。由于人与人之间的生活方式和药代动力学差异，PCBs的血浆浓度，分布和新陈代谢在个体之间可能会有很大差异。目的我们研究了丹麦健康儿童人群中血浆血浆PCB浓度与心肺健康，剧烈体育活动和脂肪量的观察关系。方法来自欧洲青年心脏研究丹麦分研究的509名儿童的∑PCB（PCB138，PCB153和PCB180），心肺功能，皮厚度和客观测量的身体活动数据。结果男孩和女孩的血浆∑PCB含量升高都与更高的健康度和更高的瘦度有关。协会之间是相互独立的，并且在控制了社会经济状况和母乳喂养的持续时间之后一直存在。我们观察到，最胖/最胖的孩子的血浆ΣPCB水平几乎是最胖/最胖的孩子的∑PCB水平的三倍。男性中，尤其是青春期女孩中，脂肪与∑PCB之间的关联最强，血浆∑PCB的减少幅度较小，而脂肪含量更高。讨论我们的发现表明增加的脂解作用会刺激PCBs释放到脉管系统中。结果是在非常健康和苗条的受试者中，PCB的血浆水平更高。这种情况很可能在多氯联苯和心脏代谢健康的流行病学观察中引起负面的混淆。同时，脂肪组织可能在促进不良健康和提供相对安全的PCB存放场所中起双重作用。