Theo Colborn: a pioneer in identifying the problems caused by endocrine disrupting chemicals

On International Women’s Day, ChemTrust wanted to highlight the work of one woman in particular who had a significant impact on the field of endocrine disrupting chemicals, Dr Theo Colborn (1927-2014)

A trained pharmacist, Theo Colborn had an interest in wildlife from an early age. After completing her Master’s degree in science in 1981, she was awarded a PhD in Zoology in 1985 at the age of 58. Colborn undertook research on contaminants in the Great Lakes on the Canada-US border, and it was this research that demonstrated how endocrine disrupting chemicals were entering the environment and altering the development of wildlife. She co-authored the book ‘Our Stolen Future’, and in 2003 founded The Endocrine Disruption Exchange (TEDX) in the US, a non-profit organisation which aims to reduce the production and use of hormone disrupting chemicals.

ChemTrust sat down with co-founder of CHEM Trust, Elizabeth Salter Green, to talk about the impact that Theo had on the field. Elizabeth previously worked as Director of the WWF-UK Toxics Programme, and has also worked for WWF’s European Policy Office, and for WWF International. Prior to WWF she worked for several years as a marine biologist, and co-authored the book “The Toxic Consumer”.

When did you first hear about Theo’s work?

I first met her when she came to the UK for the launch of her book, ‘Our Stolen Future’ in 1996. I was lucky enough to work with her on European policy on endocrine disrupting chemicals. But I had heard of her before that, as I was working for WWF-UK in the marine programme, and she was working for WWF’s US office.

What contribution did Theo make to the field of endocrine-disrupting chemicals?

Theo Colborn figured out that chemicals could disrupt our development. She was working in the Great Lakes on the Canada-US border in the 80s and could see that the populations of top predators were decreasing. She worked out – of course with the help of colleagues – that once these persistent chemicals were in the mother’s bloodstream they could be passed across to the child, be it an egg or a foetus developing in-utero. She could see that these chemicals had the ability to look like hormones and that they were disrupting the offspring’s development before they were even born. They were causing fertility problems in mammals, raptors’ shells to be too thin, and that was why the populations of top predators were decreasing. In 1991, she brought together 21 scientists from across the world to discuss hormone disrupting chemicals in the environment.

 Were there others working on similar research at the same time?

There were other people looking at chemicals and their impacts on wildlife and humans, but they were not able to work out the mechanism of the chemicals as hormone disruptors. They didn’t use the term endocrine disruptor until Theo had, and then applied the term to their own work. She absolutely led the way.

 What was the impact of her work on future research into endocrine disruptors?

She, with that group of scientists, coined the term ‘endocrine disruptor’, and it was used in all the scientific literature. In 1996, she wrote ‘Our Stolen Future’, which explained how these chemicals could be bad for not only the wildlife that she had studied, but for humans too. I remember her coming to the UK for the book launch, and she and WWF got such bad press for scaremongering. But, by the early 2000s the EU was spending €200 million on endocrine disrupting chemicals research programmes. We had gone from being vilified in 1996, to be the cause of hundreds of millions of euros being spent on research because they knew that Theo’s work was right.

 Was there any impact on policy or chemical regulation?

When Theo came to the UK in 1996, she said these endocrine disrupting chemicals are a problem. So, WWF wrote to the European Commission and told them that they are overlooking this whole group of harmful chemicals in their chemicals legislation, but we were told that nothing was going to be done. So, with Theo’s help, we got an Own Initiative report written in the European Parliament. An Own Initiative report is used if an issue is felt to be really important, but you can’t get leverage with the Commission. In this case, we were fortunate that Kirsten Jensen from the Environment Committee took the leadership in drafting  an Own Initiative report on endocrine disrupting chemicals report in 1998.  Following this report, the Commission had to do something, and that was then when they started to produce a strategy on endocrine disrupting chemicals. It is thanks to Theo Colborn, WWF and the other NGOs, that endocrine disrupting chemicals were put  on the agenda and also into REACH, which is what we use today to regulate harmful chemicals.

 What impact has Theo’s work had globally?

When she brought these scientists together in 1991 they were from all around the world, so it was truly a global group, and so her message had a global reach. There was upset amongst chemical companies and documentaries made all around the world. While she had a global impact, the only part of the world that made formal legislation on endocrine disrupting chemicals was the EU.

 What influence has Theo’s work, or working alongside her, had on your own career?

She has definitely been the inspiration for my life’s work. I personally felt, the way that she did, that unless we get on top of these endocrine disrupting chemicals we were going to undermine the wellbeing of future generations. And then it was almost a perfect storm. Theo was undertaking the research in the US, I was in the UK and understood the science and policy, WWF was the world’s largest environmental organisation, and the European Union was producing environmental legislation to try and protect human health and the environment. We eventually got the EU to include endocrine disrupting properties as a criterion for managing chemicals. That is thanks to Theo, and that is all that my life’s work has been about.

 How is Theo an inspiration for others?

One of the things about Theo is that she was quite softly spoken, she didn’t have a massive ego, she just knew her science was right. She was a woman and most of her adversaries were men in grey suits working for big chemical companies, and she had an enormous adversary in that. I felt that it was one woman espousing the science, with the whole of the chemical industry wanting to shoot her down. But she would not be put off by others, she just kept going because she knew the science was right.

 Also, she had come to this quite late in life. It wasn’t until she was in her 50s, 60s, 70s, that she produced this new hypothesis of hormone disruptors. So, I suppose that says to me, you might have had a career, or children, and be wondering what you can achieve now. Well, Theo started her whole career on endocrine disrupting chemicals in her 50s, and look at the impact that her work has had.

Written by Eleanor Hawke on March 7, 2019.
Reference. Image credit wikimedia.

Twenty-Five Years of Endocrine Disruption Science: Remembering Theo Colborn


For nearly 30 years, Dr. Theo Colborn (1927–2014) dedicated herself to studying the harmful effects of endocrine-disrupting chemicals on wildlife, humans, and the environment. More recently, she extended this effort to address the health impacts of unconventional oil and gas development. Colborn was a visionary leader who excelled at synthesizing scientific findings across disciplines. Using her unique insights and strong moral convictions, she changed the face of toxicological research, influenced chemical regulatory policy, and educated the public. In 2003, Colborn started a nonprofit organization—The Endocrine Disruption Exchange (TEDX). As we celebrate the 25th anniversary of endocrine disruption science, TEDX continues her legacy of analyzing the extensive body of environmental health research and developing unique educational resources to support public policy and education. Among other tools, TEDX currently uses the systematic review framework developed by the National Toxicology Program at the National Institute of Environmental Health Sciences, to answer research questions of pressing concern. In this article, we pay homage to the tenacious woman and the exemplary contribution she made to the field of environmental health. Recommendations for the future of the field are drawn from her wisdom.

Les liens entre les industries agroalimentaire et pharmaceutique

Interview de Vandana Shiva, Brut, Février 2019

Selon Vandana Shiva, des multinationales s’enrichissent en vendant des médicaments pour soigner des maladies qu’elles ont elles-mêmes provoquées.

L’écologiste Vandana Shiva dénonce le “cartel du poison”, Brut, Février 2019.

How chemicals can affect the health of developing children

There is an increased concern about endocrine-disrupting chemicals, especially their interference on the thyroid gland

The impact of such chemicals on thyroid hormone levels, especially those of pregnant women during the first three months of pregnancy, may result in neurodevelopmental diseases, autism and IQ loss in the unborn child.

Barbara Demeneix, Professor from the French National Museum of Natural History, explains why these chemicals affect the signalling of thyroid hormones and what we can do to protect our children.

Video published on 7 February 2018, by EUchemicals.

The negative impact of the environment on methylation/epigenetic marking in gametes and embryos

A plea for action to protect the fertility of future generations, 17 January 2019


Life expectancy has increased since World War II and this may be attributed to several aspects of modern lifestyles. However, now we are faced with a downturn, which seems to be the result of environmental issues. This paradigm is paralleled with a reduction in human fertility: decreased sperm quality and increased premature ovarian failure and diminished ovarian reserve syndromes.

Endocrine Disruptor Compounds (EDCs) and other toxic chemicals: herbicides, pesticides, plasticizers, to mention a few, are a rising concern in today environment. Some of these are commonly used in the domestic setting: cleaning material and cosmetics and they have a known impact on epigenesis and imprinting via perturbation of methylation processes. Pollution from Poly Aromatic Hydrocarbons (PAH), particulate matter (PM), <10 and <2.5 μm and ozone, released into the air all affect fertility. Poor food processing management is a source DNA adducts formation, impairing gametes quality. An important question to be answered is that of nanoparticles (NPs) that are present in food and which are thought to induce oxidative stress. Now is the time to take a step backwards. Global management of the environment and food production is required urgently in order to protect the fertility of future generations.


DES and the GENES

Impact of endocrine disrupting chemicals exposure on fecundity as measured by time to pregnancy

A systematic review;, Environmental research, 2018 Dec


Emerging scientific evidence suggests that exposure to environmental pollutants is associated with negative effects on fecundity as measured by time to pregnancy (TTP).

To conduct a systematic review of the literature on the association between selected endocrine disrupting chemicals (EDCs), and fecundity as measured by TTP in humans. Compounds included in this review are: brominated flame retardants (BFRs) such as hexabromocyclododecane, tetrabromobiphenol A and polybrominated diphenyl ethers; organophosphates flame retardants (OPFRs); and phthalates.

Scopus, MEDLINE via Ebscohost and EMBASE databases were searched for articles exploring the relationships between selected EDCs and fecundity as measured by time to pregnancy. We assessed the quality of included studies and evidence for causality was graded using the criteria developed by the World Cancer Research Fund.

14 studies of 191 full-text articles assessed for eligibility were included for qualitative synthesis. Five studies examined BFRs and 10 studies examined phthalates. Among the fourteen, one study assessed both BFRs and phthalates. There were no studies which investigated fecundity as measured by TTP on HBCD, TBBPA, or OPFRs. We recorded plausible fecundity outcomes as measured by TTP related to some of these EDCs. BFRs or phthalates increased TTP. However, results were inconsistent.

We recorded mostly weak associations between exposure to selected EDCs and fecundity. However, evidence was considered limited to conclude a causal relationship due to inconsistency of results. The health risks posed by these chemicals in exposed populations are only beginning to be recognized and prospective measurement of the environmental effects of the chemicals in large cohort studies are urgently needed to confirm these relationships and inform policies aimed at exposure prevention

Personal care product use and breast cancer risk

Associations between Personal Care Product Use Patterns and Breast Cancer Risk among White and Black Women in the Sister Study

New Research from USA NIEHS sister study of 47,000 women, suggests a link between frequent and moderate use of beauty products and breast cancer. The study reviews effects of environment and endocrine disruptors on risks of breast cancer and fibroids.

2018 Study Abstract

Many personal care products include chemicals that might act as endocrine disruptors and thus increase the risk of breast cancer.

We examined the association between usage patterns of beauty, hair, and skin-related personal care products and breast cancer incidence in the Sister Study, a national prospective cohort study (enrollment 2003–2009).

Non-Hispanic black (4,452) and white women (n=42,453) were examined separately using latent class analysis (LCA) to identify groups of individuals with similar patterns of self-reported product use in three categories (beauty, skin, hair). Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between product use and breast cancer incidence.

A total of 2,326 women developed breast cancer during follow-up (average follow-up=5.4y). Among black women, none of the latent class hazard ratios was elevated, but there were <100 cases in any category, limiting power. Among white women, those classified as “moderate” and “frequent” users of beauty products had increased risk of breast cancer relative to “infrequent” users [HR=1.13 (95% CI: 1.00, 1.27) and HR=1.15 (95% CI: 1.02, 1.30), respectively]. Frequent users of skincare products also had increased risk of breast cancer relative to infrequent users [HR=1.13 (95% CI: 1.00, 1.29)]. None of the hair product classes was associated with increased breast cancer risk. The associations with beauty and skin products were stronger in postmenopausal women than in premenopausal women, but not significantly so.

This work generates novel hypotheses about personal care product use and breast cancer risk. Whether these results are due to specific chemicals or to other correlated behaviors needs to be evaluated.

Children’s cereals contain glyphosate residues at high level, second round of tests shows

Another round of tests finds weedkiller widespread in popular cereals and snack bars

Following an initial test last August, a second round of tests commissioned by the Environmental Working Group found the active ingredient in Monsanto’s Roundup weed killer in every sample of popular oat-based cereal and other oat-based food marketed to children.

“People don’t want this pesticide on their food, especially in foods marketed to and consumed by children,”

said Tasha Stoiber, senior scientist at EWG.

Almost all of the samples tested by EWG had residues of glyphosate at levels higher than what EWG scientists consider protective of children’s health with an adequate margin of safety.

Bisphenol F (BPF) and Bisphenol S (BPS)

A Systematic Review and Comparison of the Hormonal Activity of Bisphenol A Substitutes

Systematic review is an approach to answering research questions by systematically selecting, evaluating, and integrating scientific evidence.

Evidence that BPA might be harmful to human health due to its actions as an endocrine-disrupting chemical has prompted the industry to seek alternative chemicals.

This analysis summarizes in vivo and in vitro literature and compare the hormonal potency of BPS and BPF to BPA using the in vitro studies.


Increasing concern over bisphenol A (BPA) as an endocrine-disrupting chemical and its possible effects on human health have prompted the removal of BPA from consumer products, often labeled “BPA-free.” Some of the chemical replacements, however, are also bisphenols and may have similar physiological effects in organisms. Bisphenol S (BPS) and bisphenol F (BPF) are two such BPA substitutes.

This review was carried out to evaluate the physiological effects and endocrine activities of the BPA substitutes BPS and BPF. Further, we compared the hormonal potency of BPS and BPF to that of BPA.

We conducted a systematic review based on the Office of Health Assessment and Translation (OHAT) protocol.

We identified the body of literature to date, consisting of 32 studies (25 in vitro only, and 7 in vivo). The majority of these studies examined the hormonal activities of BPS and BPF and found their potency to be in the same order of magnitude and of similar action as BPA (estrogenic, antiestrogenic, androgenic, and antiandrogenic) in vitro and in vivo. BPS also has potencies similar to that of estradiol in membrane-mediated pathways, which are important for cellular actions such as proliferation, differentiation, and death. BPS and BPF also showed other effects in vitro and in vivo, such as altered organ weights, reproductive end points, and enzyme expression.

Based on the current literature, BPS and BPF are as hormonally active as BPA, and they have endocrine-disrupting effects.

Pesticide Damage to DNA Found ‘Programmed’ into Future Generations

Atrazine induced epigenetic transgenerational inheritance of disease, lean phenotype and sperm epimutation pathology biomarkers

Dr. Paul Winchester, a pediatrician, and several other researchers including Michael Skinner, professor of biology at Washington State University’s Center for Reproductive Biology, conducted a study to see if there was a link between atrazine in drinking water and birth defects, EcoWatch reports.

“The most alarming (finding) to me is that almost every chemical tested including atrazine reduced fertility in the third generation of offspring.”

2017 Study Abstract

Ancestral environmental exposures to a variety of environmental toxicants and other factors have been shown to promote the epigenetic transgenerational inheritance of adult onset disease. The current study examined the potential transgenerational actions of the herbicide atrazine.

Atrazine is one of the most commonly used herbicides in the agricultural industry, in particular with corn and soy crops. Outbred gestating female rats were transiently exposed to a vehicle control or atrazine. The F1 generation offspring were bred to generate the F2 generation and then the F2 generation bred to generate the F3 generation. The F1, F2 and F3 generation control and atrazine lineage rats were aged and various pathologies investigated. The male sperm were collected to investigate DNA methylation differences between the control and atrazine lineage sperm. The F1 generation offspring (directly exposed as a fetus) did not develop disease, but weighed less compared to controls. The F2 generation (grand-offspring) was found to have increased frequency of testis disease and mammary tumors in males and females, early onset puberty in males, and decreased body weight in females compared to controls. The transgenerational F3 generation rats were found to have increased frequency of testis disease, early onset puberty in females, behavioral alterations (motor hyperactivity) and a lean phenotype in males and females. The frequency of multiple diseases was significantly higher in the transgenerational F3 generation atrazine lineage males and females. The transgenerational transmission of disease requires germline (egg or sperm) epigenetic alterations. The sperm differential DNA methylation regions (DMRs), termed epimutations, induced by atrazine were identified in the F1, F2 and F3 generations. Gene associations with the DMRs were identified. For the transgenerational F3 generation sperm, unique sets of DMRs (epimutations) were found to be associated with the lean phenotype or testis disease. These DMRs provide potential biomarkers for transgenerational disease.

The etiology of disease appears to be in part due to environmentally induced epigenetic transgenerational inheritance, and epigenetic biomarkers may facilitate the diagnosis of the ancestral exposure and disease susceptibility. Observations indicate that although atrazine does not promote disease in the directly exposed F1 generation, it does have the capacity to promote the epigenetic transgenerational inheritance of disease.

The Dangers of Plastic Food Packaging : Food Additives and Child Health Report

Chemicals in Food May Harm Children, Pediatricians’ Group Says

In their Policy Statement and Technical Report, the American Academy of Pediatrics is urging families to limit the use of plastic food containers, cut down on processed meat during pregnancy and consume more whole fruits and vegetables rather than processed food.

Such measures would lower children’s exposures to chemicals in food and food packaging that are tied to health problems such as obesity, Roni Caryn Rabin reports. Featured image credit from Pexels.

2018 Technical Report Abstract

Increasing scientific evidence suggests potential adverse effects on children’s health from synthetic chemicals used as food additives, both those deliberately added to food during processing (direct) and those used in materials that may contaminate food as part of packaging or manufacturing (indirect). Concern regarding food additives has increased in the past two decades in part because of studies that increasingly document endocrine disruption and other adverse health effects. In some cases, exposure to these chemicals is disproportionate among minority and low-income populations. This report focuses on those food additives with the strongest scientific evidence for concern. Further research is needed to study effects of exposure over various points in the life course, and toxicity testing must be advanced to be able to better identify health concerns prior to widespread population exposure. The accompanying policy statement describes approaches policy makers and pediatricians can take to prevent the disease and disability that are increasingly being identified in relation to chemicals used as food additives, among other uses.