Endocrine-disrupting chemicals and child health

Endocrine-disrupting chemicals (EDCs) are chemicals which are introduced into the environment by human activities. In many cases it has been proven that EDCs can cause adverse health effects in the human. EDCs are classified by their chemical structure, putative direct or indirect effects on endocrine glands and systems, may accumulate and persist in organisms and in the environment, and/or they may exert clinically observable and measurable effects. Often, EDCs may act in concert and as mixtures. Legislation to ban EDCs and protect especially pregnant women and children at young age are needed and needs to be revised and adjusted to new developments on a regular basis. Putative associations, in spite of sometimes conflicting results, have to be analyzed in in vitro model systems be it in cell biology, in vitro settings or animal studies in more detail. This chapter depicts the mainly positive albeit detrimental epidemiological findings for EDC-caused effects in the fields of growth and metabolism, neurocognitive development and sexual development and reproduction.

Introduction

Endocrine-disrupting chemicals (EDCs) are chemical substances which are introduced into the environment by human activities and actions. It is hypothesized, and in many cases proven, that EDCs can cause adverse health effects for humans through interaction with endocrine systems [1,2]. They are classified by their chemical structure, putative direct or indirect effects on endocrine glands and systems, may accumulate and persist in organisms and in the environment, and/or they may exert clinically observable and if at all possible measurable effects. Unfortunately, for analysis and research of the complex mechanisms of their actions in the human body, only in vitro model systems have so far been available [[3], ∗[4], [5]]. For most of these systems insufficient or even no high-throughput capacity is available- This makes risk evaluation very difficult in many cases. In addition and importantly, in industrial countries, most people are often exposed to a rather wide variety of mixtures of substances at the same time, in various locations and/or in a consecutive order. All substances by themselves and all mixtures and combinations of these might cause variable and diverse effects or may exert additive and/or combined effects. In addition, the clinical importance of epigenetic and importantly transgenerational changes caused by the action of EDCs during vulnerable phases of development is currently unclear [6]. Epidemiological studies have often been criticized because reproducibility of these has not always been possible and is not always guaranteed. In addition, results vary between for example populations and cohorts studied and also depend upon the times when studies have been conducted and under which legislative regulations environmental conditions have been analyzed [5]. Nevertheless, epidemiological studies remain the method of choice for the detection and analysis of suitable model systems and to develop hypotheses for translational and basic research on putative effects of EDCs on human health (see Table 1). To detect putative associations, in spite of sometimes conflicting results, is crucial in the selection of factors that can then be analyzed for example in in vitro model systems be it in cell biology, in vitro settings or animal studies in more detail [7]. This chapter depicts the mainly positive albeit detrimental epidemiological findings for EDC-caused effects in the fields of growth and metabolism, neurocognitive development and sexual development and reproduction in a descriptive and personalized way. As has been pointed out already, that there is a strong need for direct linkage between epidemiological studies and mechanistic research using model systems, especially focusing on the interaction of different EDCs and mixtures thereof and the consequences of prenatal and early life exposure [1,[5], [6], ∗[7]].