Interventions needed to reduce exposure to obesity-promoting chemicals
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Exposure to three common endocrine-disrupting chemicals can increase the risk for obesity, and their elimination may improve public health while also producing economic benefits, according to a speaker.
Leonardo Trasande, MD, MPP, the Jim G. Hendrick Professor of Pediatrics, vice chair for pediatric and director of environmental pediatrics, and professor of environmental medicine and population health at the New York University School of Medicine, said exposure to chemicals that increase risk for obesity and cardiometabolic diseases with repeat exposure plays just as important of a role in the development of obesity as diet and physical activity. However, while diet and physical activity interventions can be difficult to maintain, Trasande said, people can take easy action steps to reduce exposure to these obesogens.
“We know that regulatory, as well as manufacturing changes, can induce substantial changes in exposure, that thereby reduce substantial levels detected in humans, thereby reducing potential disease burden associated with obesity and diabetes, as well as other conditions early in life that are linked to these chemicals,” Trasande said during a presentation at the European Society for Paediatric Endocrinology virtual meeting. “We know that the cost that can be traced to these exposures are substantial at a societal level, with the safer alternatives potentially producing health and economic benefits that outweigh the potential costs.”
Chemical exposure and childhood obesity
Studies have identified three types of endocrine-disrupting chemicals as obesogens:
- Bisphenols are commonly found in the lining of aluminum cans and thermal paper receipts.
- Phthalates are often found in shampoos, soaps, lotions, flooring and food wrap.
- Perfluoroalkyl substances (PFAS) are found in nonstick cooking items, carpet and upholstery and microwave popcorn bags.
In a population-based prospective birth cohort study conducted at Erasmus Medical Center in Rotterdam, the Netherlands, bisphenols and phthalate metabolites were measured in spot urine samples during the first, second and third trimester of a mother’s pregnancy, and at age 6 years in children. There were 1,431 mother-infant pairs included in the study.
During pregnancy, exposure to phthalic acid was associated with lower fetal weight through 40 weeks postpartum. Mothers who were exposed to mono(2-ethyl-5-oxohexyl) phthalates had an increased risk for preterm birth (OR = 1.43; 95% CI, 1.03-1.97). Exposure to monobenzyl phthalates was associated with higher odds for small for gestational age at birth (OR = 1.32; 95% CI, 1.04-1.68).
In addition, postnatal growth was hampered by obesogen exposure. Pregnancy-averaged total bisphenol exposure was associated with lower childhood BMI, with a stronger association found among girls. First trimester bisphenol S exposure was associated with lower bone mineral density and bone mineral content at age 10 years. Youths exposed to high-molecular-weight phthalates had a higher BMI standard deviation score at age 10 years, and dioctyl phthalate exposure at age 6 years was associated with a greater likelihood for overweight at age 6 years (OR = 1.47; 95% CI, 1.11-1.93) and age 10 years (OR = 1.48; 95% CI, 1.12-1.96).
PFAS have also been associated with childhood overweight. In a meta-analysis of 24 studies, maternal or cord blood exposure to 1 ng/mL of perfluorooctanoic acid was associated with a mean 10.5 g decrease in birth weight. In another meta-analysis of 10 studies, every 1 ng/mL of perfluorooctanoic acid found in maternal blood increased the likelihood of childhood overweight by 25% and BMI z score by 0.1 U.
Limiting obesogen exposure
Trasande said there are several steps families can take to limit exposure to obesity-promoting chemicals:
- Limit the intake of canned or processed foods.
- Avoid microwaving plastic containers or washing them in dishwasher.
- Avoid plastic bottles with recycling numbers 3, 6 or 7.
- Do not reuse single-use plastic bottles.
- Plastic food containers should be thrown away if they are etched.
- Use stainless steel or cast-iron cookware.
- Replace old furniture with exposed foam, or cover it.
- Recirculate indoor air with outdoor air for a few minutes each day.
- Prevent dust by vacuuming regularly with a HEPA filter and mopping.
Policymakers can also take action to reduce obesogen exposure, according to Trasande. In one study, researchers estimated the cost of replacing bisphenol A (BPA) in aluminum cans with oleoresin, a safer substitute. The cost of replacing BPA with oleoresin was about $0.022 per can. It would cost about $2.2 billion for oleoresin to replace BPA in the 100 billion aluminum cans produced annually worldwide. Researchers estimated replacing BPA would save $1.74 billion in costs from the prevention of childhood obesity and adult cardiovascular disease. The estimate does not include other health effects, and sensitivity analyses suggest cost savings as high as $13.8 billion.
Trasande noted the benefits are predicated on finding a healthy alternative lining for aluminum cans. Instead, he said, companies have replaced BPA with other similar chemicals.
“There are now 40-some chemically similar replacements of BPA now in use,” Trasande said. “These would include bisphenol S, which is just as estrogenic, as persistent in the environment, and has toxic embryos. What we’ve done in practice, because of a weak regulatory framework, is whacked the mole and regrettably substituted, undermining the potential benefits that can be attained.”
Trasande also noted larger studies on the effects of obesogens on the health of children are needed. Several projects around the world are currently taking place to obtain larger sample size data, including the NIH’s Environmental Influences on Child Health Outcomes (ECHO) program and the LifeCycleEU Child Cohort Network.
“Perhaps we might unite these data together with the Japan Environment and Children’s Study, the Chinese birth cohort designs, as well as Australian and other studies, to examine chemical exposure data and identify mechanisms by which these chemicals contribute to obesity, diabetes as well as other downstream consequences,” Trasande said.
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Trasande L. WGS 4.1. Presented at: European Society for Paediatric Endocrinology Annual Meeting; Sept. 22-26, 2021 (virtual meeting).
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