Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, NO-0403 Oslo, Norway.
Norwegian Institute of Public Health, P.O. Box 4404 Nydalen, NO-0403 Oslo, Norway.
Environ Int. 2015 Dec;85:156-62. doi: 10.1016/j.envint.2015.08.011. Epub 2015 Sep 19.
Infants are exposed to persistent environmental contaminants through breast milk, yet studies assessing the health effects of postnatal exposure are lacking. Existing postnatal exposure assessment is either too simple (lactation exposure model, LEM) or requires complex physiologically-based pharmacokinetic (PBPK) models.
We present equations for postnatal exposure calculations. We applied these equations to study the effect of hexachlorobenzene (HCB) on infant growth in the two first years of life.
HCB was measured in breast milk samples in 449 mother-child pairs participating in the Norwegian birth cohort study HUMIS. We used these concentrations, mother's weight, height and age, together with child's weight at 8 age points, and proportion of milk consumed each month, to calculate HCB concentrations in the infant over age. We then estimated the association between HCB and infant growth using a linear mixed model.
Children exposed to HCB via mother's milk reached concentrations 1-5 times higher than the mother. HCB was associated with lower weight gain in the first 2years (-33g per unit HCB and month, 95% CI: -38, -27 at 6months). Associations were stronger during the first 3months (-57g per unit HCB and month, 95% CI: -67, -49 at 1month), indicating a critical window of effect. Our equations gave more precise estimates than the LEM.
Our equations for postnatal exposure of lipophilic environmental toxicants give better results than the LEM and are easier to implement than the complex PBPK models. HCB exposure, especially during the first three months of life, has a negative effect on infant growth up to 2years.
婴儿通过母乳接触到持久性环境污染物，但缺乏评估产后暴露对健康影响的研究。现有的产后暴露评估要么过于简单（哺乳暴露模型，LEM），要么需要复杂的基于生理学的药代动力学（PBPK）模型。
我们提出了用于产后暴露计算的方程。我们应用这些方程来研究六氯苯（HCB）对婴儿在生命的头两年生长的影响。
在 449 对参与挪威出生队列研究 HUMIS 的母婴对中，我们测量了母乳样本中的 HCB 浓度。我们使用这些浓度、母亲的体重、身高和年龄，以及孩子在 8 个年龄点的体重和每月消耗的母乳比例，计算了婴儿在年龄增长过程中的 HCB 浓度。然后，我们使用线性混合模型估计 HCB 与婴儿生长之间的关联。
通过母乳暴露于 HCB 的儿童达到的浓度比母亲高 1-5 倍。HCB 与前 2 年体重增长较慢有关（每单位 HCB 和月-33 克，95%CI：-38，-27 在 6 个月）。在头 3 个月的关联更强（每单位 HCB 和月-57 克，95%CI：-67，-49 在 1 个月），表明存在一个关键的作用窗口。我们的方程比 LEM 给出了更精确的估计。
我们的亲脂性环境毒物产后暴露方程比 LEM 效果更好，而且比复杂的 PBPK 模型更容易实施。HCB 暴露，特别是在生命的头三个月，对婴儿生长到 2 岁有负面影响。
