Consensus statement: Endocrine-disrupting chemicals pose potential threat to children

In a recently published consensus statement, the European Society for Paediatric Endocrinology and the Pediatric Endocrine Society alert physicians to the possible dangers of endocrine-disrupting chemicals and encourage them to participate in research on their effects.

“Experimental animal and wildlife studies have shown that ubiquitous chemicals can function as disrupters of the endocrine systems, either by interaction with hormone receptors or with hormone synthesis and metabolism,” one of the statement’s authors, Niels Erik Skakkebæk, MD, of Rigshopitalet, University Department of Growth and Reproduction in Denmark, told Endocrine Today. “However, so far, clinicians have been less aware of the problem.”

Problems for pediatric patients

Concerns about exposure to endocrine-disrupting chemicals would be hypothetical, except for the “many endocrine problems [with] no known etiology,” such as reproductive issues, certain cases of obesity and some thyroid disorders, according to Skakkebæk. For example, the statement cites cohort studies indicating that 2% to 9% of newborns in the United Kingdom and Nordic countries have cryptorchidism. The authors note that any upward trends in these results may mirror data on increasing incidence of testicular cancer — a disease which is now suspected to have fetal origins. In addition, Skakkebæk noted that animal studies suggest dysgenesis of fetal testis related to endocrine disrupters may also cause reproductive problems.

“The pediatric endocrine societies are the ideal organizations to call attention to these problems, as there is growing concern that the fetus and the growing child may be particularly vulnerable [to endocrine-disrupting chemicals],” Skakkebæk said. “In fact, it appears that several endocrine problems in childhood and adult life have fetal origin, although [this is] not always noticeable during the first years of life.”

Moving forward

Conflicting data from animal and human epidemiological studies further complicate the issue. Inconsistent evidence hinders the ability of public health and government regulatory agencies to make important decisions about manufacturing of certain chemicals, the document states.

“Exposure to endocrine disrupters is complex. We are all exposed daily to minute amounts of mixtures of them through our modern lifestyles,” Skakkebæk said. “The crucial question is whether they may also be harmful for us. We need commitment from clinicians to unravel the possible roles of endocrine disrupters.”

For more information:

• Skakkebæk NE. J Clin Endocrinol Metab. 2011;doi:10.1210/jc.2011-1269.

Disclosure: Dr. Skakkebæk reports no relevant financial disclosures. One author reports receiving lecture fees from Novo Nordisk and grant support from the Sigrid Juselius Foundation.

The joint statement by European Society for Paediatric Endocrinology and the Pediatric Endocrine Society highlights the fact that infants and young children are particularly susceptible to endocrine-disrupting chemical exposure, due to their passage across the placenta and into breast milk and because infants and young children are most prone to mouthing on plastics and are frequently dressed in flame retardant clothing.

Robert H. Lustig, MD

Implicating endocrine-disrupting chemical exposure with endocrine outcomes in humans is problematic, in that the best we usually have is cross-sectional data, which is complicated by lack of directionality, and the fact that most endocrine-disrupting chemicals are lipophilic compounds which store in adipose tissue, making blood levels difficult to interpret. Mechanistic and/or prospective data are extremely difficult to come by in humans, let alone children. However, predictive data are beginning to accumulate. For instance, the degree of organophosphate or organochlorine (pesticides) exposure during pregnancy predicts cognitive dysfunction in the offspring, possibly through effects on thyroid metabolism (Bouchard MF. Environ Health Perspect. 2011;119:1189-1195 and Chevrier J. Am J Epidemiol. 2008;168:298-310). On the obesity front, intrauterine exposure to DDE (pesticide; a metabolite of DDT, banned in the U.S. in 1972) and PCBs (coolants and electrical equipment) predict BMI z-scores in toddlers aged 1 to 3 years (Verhulst SL. Environ Health Perspect. 2009;117:122-126 and Mendez MA. Environ Health Perspect. 2011;119:272-278). Lastly, prenatal exposure to hexachlorobenzene (fungicide) predicted elevated risk for obesity at 6 years (Smink A. Acta Paediatr. 2008;97:1465-1469).

The implications of these studies are that exposure to endocrine-disrupting chemicals during pregnancy are particularly egregious for negative effects on outcomes in children that predict disease, socioeconomic health disparities and excessive utilization of medical resources. Such exposures are even more alarming, as these compounds are ubiquitous and persist in the environment, suggesting that the worst is yet to come.

– Robert H. Lustig, MD
Professor of Pediatrics, Division of Endocrinology
University of California, San Francisco

Disclosure: Dr. Lustig reports no relevant financial disclosures.

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