Prenatal Phthalates Exposure and Cord Thyroid Hormones: A Birth Cohort Study in Southern Taiwan

Exploring the associations between phthalate exposure and cardiometabolic risk factors clustering among children: The potential mediating role of insulin-resistant-related genes DNA methylation

The relationship between childhood phthalates (PAEs) exposure, DNA methylation, and cardiometabolic risk (CMR) factors is not well understood. Children were included from a longitudinal cohort 2018-2020 in Xiamen, China. A nest case-control study was additionally conducted, and methylation in lysyl oxidase-like 3 (LOXL3) and solute Carrier Family 6 Member 19 (SLC6A19) were measured. Generalized linear models were used to estimate the associations between PAEs exposure and CMR factors, and mediation analyses of DNA methylation were conducted. The longitudinal study included 835 children aged 7-11 years, and the nest case-control study included 120 cases and 120 controls. Exposure to higher PAEs was correlated with increased CMR scores at baseline (β = 0.299, 95 %CI = 0.114, 0.485) and the final visit (β = 0.202, 95 %CI = 0.008, 0.397). In nest case-control study, higher mono-n-butyl phthalate (MnBP) exposure was related with elevated triglycerides (TG) (β = 0.283, 95 %CI = 0.025, 0.540). A decrement of methylation of CpG 33.34 of LOXL3 was found in response to MnBP exposure (β = -0.014, 95 %CI = -0.027, -0.001). Furthermore, increased methylation of LOXL3_CpG 33.34 and SLC6A19_CpG 11.12 was related to reduced TG. De-methylation of LOXL3_CpG 33.34 and SLC6A19_CpG 11.12 could mediate MnBP-TG pathways. Childhood exposure to PAEs was associated with increased CMR scores, and mediation of PAE exposure on childhood cardiometabolic health by LOXL3 and SLC6A19 de-methylation was observed.

Endocrine Disruptor Chemicals and Children's Health

We are all exposed to endocrine-disrupting chemicals (EDCs) starting from embryonic life. The fetus and child set up crucial developmental processes allowing adaptation to the environment throughout life: they are extremely sensitive to very low doses of hormones and EDCs because they are developing organisms. Considering the developmental origin of well-being and diseases, every adult organism expresses consequences of the environment in which it developed. The molecular mechanisms through which the main EDCs manifest their effects and their potential association with endocrine disorders, such as diabetes, obesity, thyroid disease and alteration of adrenal hormones, will be reviewed here. Despite 40 years having passed since the first study on EDCs, little is yet known about them; therefore, our purpose is to take stock of the situation to establish a starting point for further studies. Since there is plenty of evidence showing that exposure to EDCs may adversely impact the health of adults and children through altered endocrine function-suggesting their link to endocrinopathies-it is essential in this context to bear in mind what is already known about endocrine disruptors and to deepen our knowledge to establish rules of conduct aimed at limiting exposure to EDCs' negative effects. Considering that during the COVID-19 pandemic an increase in endocrine disruptor effects has been reported, it will also be useful to address this new phenomenon for better understanding its basis and limiting its consequences.

New insights on the effects of endocrine-disrupting chemicals on children

OBJECTIVE

Endocrine disrupting chemicals (EDCs) are present in many areas and materials of the common life, and exposure to these chemicals can occur from products to personal care, from air and food. This review aims to summarize the more recent epidemiological findings for the impact of EDCs on endocrine system health in children, including effects in growth, metabolism, sexual development, and reproduction.

SOURCES

The MEDLINE database (PubMed) was searched on August 24th, 2021, filtering for EDCs, endocrine disruptors, children, and humans.

SUMMARY OF THE FINDINGS

Intrauterine exposure of EDCs can have transgenerational effects, thus laying the foundation for disease in later life. The dose-response relationship may not always be predictable as even low-level exposures that may occur in everyday life can have significant effects on a susceptible individual. Although individual compounds have been studied in detail, the effects of a combination of these chemicals are yet to be studied to understand the real-life situation where human beings are exposed to a "cocktail effect" of these EDCs. Epidemiological studies in humans suggest EDCs' effects on prenatal growth, thyroid function, glucose metabolism, obesity, puberty, and fertility mainly through epigenetic mechanisms.

CONCLUSIONS

EDCs cause adverse effects in animals, and their effects on human health are now known and irrefutable. Because people are typically exposed to multiple endocrine disruptors, assessing public health effects is difficult. Legislation to ban EDCs and protect especially pregnant women and young children is required and needs to be revised and adjusted to new developments on a regular basis.