Endocrine disruptors (EDs) act by disrupting the body’s hormonal functions. As a result, the activity of the endocrine glands—which produce the various hormones essential to our health, balance, and development—can be altered.
EDs can disrupt all endocrine functions:

• Reproductive functions

• Thyroid functions

• Adrenal functions

• Metabolism

• Neurodevelopment, etc.

Through these effects, they are suspected of contributing to numerous chronic or developmental conditions: hormonal disorders and their consequences (infertility, precocious puberty, obesity, thyroid disease...), as well as congenital malformations, hormone-dependent cancers, and even immune disorders.
The weight of evidence evolves regularly based on new findings from published studies. The second joint report by the WHO and the United Nations Environment Programme, published in late 2012, assessed the body of evidence since 2002—the date of the previous report—and provided a scientific overview of current knowledge on this subject.
Significant concerns have been raised by the scientific and public communities regarding the potential health impacts of these substances, which are present in the environment or in consumer products.

Numerous questions regarding effects on humans

Certain effects of endocrine disruptors were initially observed in wildlife. They were subsequently widely observed in experimental animal studies. However, extrapolating these results to humans or demonstrating effects in humans raises numerous questions and challenges related to the specific mechanisms of action of endocrine disruptors:

• Numerous studies show that sensitivity to endocrine disruptors can vary depending on life stages, with particular sensitivities during developmental periods (fetal period, early childhood, puberty)

• The “non-classical” toxicity mechanisms of endocrine disruptors are also the subject of much debate. Some effects of endocrine disruptors may occur at very low doses, or dose-response relationships may be non-monotonic. “Non-monotonic” dose-response relationships refer to health effects that do not necessarily increase continuously with dose

• Some studies show that effects can manifest across multiple generations and not just in the exposed generation.

• Numerous studies demonstrate the “mixture” effects of EDs: the observation of an effect from a mixture of several substances, even though each substance taken individually has no detectable effect: “something out of nothing.”

Long-term monitoring is necessary

The epidemiological identification of effects in humans faces all these challenges and requires monitoring of sufficiently large populations over the long term (cohorts), or even across multiple generations, with a thorough characterization of exposures—a process that is time-consuming, difficult, and costly to carry out. This is why it is necessary to take into account all types of studies and data (in animals, in wildlife, modeling, biomonitoring studies, and various types of epidemiological studies) and analyze them to build the body of evidence in this field. This is what the WHO does, in particular.

The compounds suspected of being endocrine disruptors are numerous and varied. These substances are found in all environments (water, soil, air, food). Exposure routes are numerous, and virtually the entire population is exposed, as demonstrated by a recent biomonitoring study of pregnant women.
Understanding the attributable role of endocrine disruptors in the onset of diseases—which are often multifactorial—thus requires the development of methodologies that provide an integrative view of humans within their environment. This also requires monitoring certain diseases of interest in order to address scientific and societal controversies on this subject and to quantify the magnitude of the health problem (incidence estimation).

A National Strategy on Endocrine Disruptors

Since 2014, France has had a National Strategy on Endocrine Disruptors (SNPE). This strategy sets as its primary objective the reduction of exposure of the population and the environment to endocrine disruptors.

It is structured around four pillars:

• Research, assessment, monitoring

• Expertise on substances

• Regulation and substitution of endocrine disruptors

• Training and information

Since its adoption, the SNPE has been implemented through various plans and programs.
The development of the second National Strategy on Endocrine Disruptors (SNPE2) is currently underway.

For its part, Santé publique France is already implementing, at the national level, epidemiological surveillance of prioritized health indicators, using existing databases—where possible, long-term ones—covering the entire territory, as well as monitoring the population’s biological exposure to these substances (biomonitoring). This approach is part of the National Strategy on Endocrine Disruptors and the 3rd National Health and Environment Plan.