Erken Çocuklukta Gelişimsel Sorunlar ve Endokrin Bozucular
Authors: Özmert Elif N. 
Published: August 2022

Not only the prevalence of neurodevelopmental disorders but also the number of chemicals in the human body, endocrine-disrupting chemicals and neurotoxic chemicals are increasing. At least some of the increase in the prevalence of neurodevelopmental disorders can be attributed to environmental chemicals. In this chapter, intellectual development, autism spectrum disorders, and behavioral problems will be discussed. Gene and environment interaction during fetal life programs adult health and diseases. Nutrition, stress, and chemicals are the essential environmental factors. The effects of these environmental factors are also vital during the first 2 years of life. Due to the close interaction of the endocrine system with neurologic development, endocrine disruptors can also be defined as neuroendocrine disruptors. In this chapter, heavy metals (lead, mercury, cadmium, arsenic, manganese), plasticizers (phthalates, bisphenols, perfloroalkyl compounds-PFAS, PFUA), pesticides (organochlorines, organophosphates, atrzain), solvents (glycolether), flame retardants (polybrominated diphenyl ether-PBDE), persistent organic pollutants (PCB, dioxins) will be discussed. Endocrine-disrupting chemicals express their neurotoxic effect in several mechanisms; hypothalamopitutier-gonadal/adrenal axis dysfunction, thyroid hormone, immune dysregulation/inflammation, oxidative stress, neurotransmitter system, apoptosis, the prefrontal cortex- hippocampus structure and function, and epigenetic mechanisms and may differ according to sex. Strong evidence for the neurotoxic effects has been demonstrated for several chemicals, and they have been banned (lead in gasoline, PCB, OP pesticides etc). Unfortunately, This Is Not The Case For Those Chemicals Which Are Not Stored In The Body, especially the plasticizers. Plasticizers are widely used, and the populations have high exposure. Most studies show an adverse effect of plasticizers on neurodevelopment. However, the time points, the metabolites studied, and the methods used for neurodevelopment assessment differ among studies. In fact, even a small decrease in IQ, which may not be significant for the individuals, can make essential deviance for the whole population. Now the exposures are with multiple chemicals. The non-monotonic dose-response curve makes it difficult to define a safe lower limit. Exposure during the critical life periods (starting before conception, first 1000 days, adolescence) has a silent latency period where the effect is seen later. Endocrine-disrupting chemicals are not only affecting human health but also the biodiversity balance. We are not encountering many high dose acute toxicity cases but relatively low dose continuous exposures, which will manifest in the future 10 years. Now we are in a period of a silent pandemic for chemical toxins. The main issue is that all new chemicals and technologies are considered safe unless proven otherwise. In fact, we should all keep in mind that “absence of evidence is not the evidence of absence”. As a first step, awareness about the health effects and prevention of endocrine-disrupting chemicals among health care workers and the population could be increased, leading to changes in production, consumption, and lifestyle.