Environmental chemical obesogens, what can we do?
Authors: Tim Lobstein
Journal: The Lancet Diabetes & Endocrinology (2024)

Virtually every country in the world has shown a dramatic increase in the prevalence of overweight and obesity since the 1980s. Rapidly changing dietary patterns, reductions in physical activity, and increased sedentary behaviour are assumed to be the main drivers of this rising trend, but there is increasing concern that they do not adequately explain the epidemic levels of obesity.1Mozaffarian D Perspective: obesity— an unexplained epidemic.Am J Clin Nutr. 2022; 115: 1445-1450Summary Full Text Full Text PDF PubMed Scopus (0) Google Scholar Another suspect has emerged in the past decade, namely human exposure to endocrine disrupting chemicals (EDCs), also referred to as chemical obesogens.2Lobstein T Brownell KD Endocrine-disrupting chemicals and obesity risk: a review of recommendations for obesity prevention policies.Obes Rev. 2021; 22e13332Crossref Scopus (18) Google Scholar There are multiple sources of EDCs, from agricultural chemicals and cosmetic products to plastic particles and plasticisers used in the building trade, furniture, electronics, children's toys, and food packaging. EDCs have been an area of concern for their potential carcinogenic and disruptive effects on fertility, sexual development, child growth, and neurological function, but there is now increasing evidence that EDCs influence weight regulation, adipose cell formation, and appetite control.3Flaws J Damdimopoulou P Patisaul HB Gore A Raetzman L Vandenberg LN Plastics, EDCs and Health: a guide for public interest organisations and policy-makers on endocrine disrupting chemicals & plastics. Endocrine Society, 2020https://ipen.org/sites/default/files/documents/edc_guide_2020_v1_6ew-en.pdfDate accessed: March 20, 2024Google Scholar These obesogenic effects have been shown to occur in animal models from quantities found in common food packaging and household products.3Flaws J Damdimopoulou P Patisaul HB Gore A Raetzman L Vandenberg LN Plastics, EDCs and Health: a guide for public interest organisations and policy-makers on endocrine disrupting chemicals & plastics. Endocrine Society, 2020https://ipen.org/sites/default/files/documents/edc_guide_2020_v1_6ew-en.pdfDate accessed: March 20, 2024Google Scholar There is also evidence of these obesogenic effects in human populations. The plastic additive bisphenol A (BPA) is one of the most often cited potential obesogenic EDCs, and a meta-analysis of epidemiological surveys4Wu W Li M Liu A et al.Bisphenol A and the risk of obesity a systematic review with meta-analysis of the epidemiological evidence.Dose Response. 2020; 18 (1559325820916949)Crossref Scopus (62) Google Scholar found that for every 1 ng/mL increase in the concentration of urinary BPA, the odds of obesity rose by 15% for adults and 17% for children. US Centers for Disease Control and Prevention surveys show that the US population typically has a concentration range from less than 1 ng/mL to greater than 10 ng/mL.5US National Center for Environmental HealthDivision of Laboratory SciencesFourth national report on human exposure to environmental chemicals updated tables, January 2019, volume one. US Centers for Disease Control and Prevention, 2019https://stacks.cdc.gov/view/cdc/75822Date accessed: March 20, 2024Google Scholar In a 2013 study, children with the lowest quartile of urinary BPA concentration showed obesity prevalence of 10%, while children in the upper three quartiles showed obesity prevalence of 17–23%.6Bhandari R Xiao J Shankar A Urinary bisphenol A and obesity in US children.Am J Epidemiol. 2013; 177: 1263-1270Crossref PubMed Scopus (130) Google Scholar These dose–response statistics can be compared with studies showing that the risk of obesity increased 13% per hour of television that children watch per day,7Zhang G Wu L Zhou L Lu W Mao C Television watching and risk of childhood obesity: a meta-analysis.Eur J Public Health. 2016; 26: 13-18Crossref PubMed Scopus (0) Google Scholar that unhealthy diets were associated with an increased risk of obesity by 5–14%,8Schlesinger S Neuenschwander M Schwedhelm C et al.Food groups and risk of overweight, obesity, and weight gain: a systematic review and dose-response meta-analysis of prospective studies.Adv Nutr. 2019; 10: 205-218Summary Full Text Full Text PDF PubMed Scopus (229) Google Scholar and that consumption of sugar-sweetened beverages increased obesity risk by 21% per 250 mL per day.9Fresán U Gea A Bes-Rastrollo M Ruiz-Canela M Martínez-Gonzalez MA Substitution models of water for other beverages, and the incidence of obesity and weight gain in the SUN cohort.Nutrients. 2016; 8: 688Crossref Scopus (0) Google Scholar However, whether it is the sugar in these beverages or the EDCs in plastic bottles and can linings that are more obesogenic remains to be seen. The case for taking action is strong, but what is the solution? There are three types of risk management that policy makers usually consider when faced with rising obesity levels. The first is to focus on individual action with the language of personal choice, health education, campaigns to raise public awareness, and advice for people with overweight and obesity. However, individuals cannot easily avoid invisible chemicals that could be in their food, water, cosmetics, or household furnishings. Secondly, risk management can be directed towards medical interventions, including screening for individual susceptibility to EDCs and treatment regimens to counter the effects of EDCs. However, screening individuals—either for the range of possible EDCs or for their susceptibility to them—is not a possibility, and nor are EDC-specific treatments, especially for people with exposure to multiple EDCs. Lastly, risks can be managed with population-level interventions, including regulation on the use of EDCs in industry, requirements for stringent risk assessments of novel compounds, and restricted product licensing and import controls. Regulation is already under consideration: the United Nations Sustainable Development Goals (SDGs) have several targets concerning the effects of chemical pollutants on health, although obesity is not included. The SDGs provide an opportunity to link obesity prevention with environmental improvements, including reduced use of agrichemicals, petrochemicals, and plastics, and cleaner water supplies. However, these goals depend on national support, which can be politically problematic in countries that have a substantial chemicals industry sector. For instance, many countries have declined to sign the Stockholm Convention on Persistent Organic Pollutants, including the USA, Italy, and Malaysia. This lack of national support highlights the need for stronger advocacy, including more frequent statements from professional bodies, citizen demands for labelling of products containing EDCs, trading restrictions with countries that are not parties to the Stockholm Convention, and perhaps some exemplary legal actions taken against major EDC producers or commercial users. TL is a Senior Policy Advisor for The World Obesity Federation. The World Obesity Federation receives occasional educational grants from suppliers of weight management products. I declare no other competing interests.