Environmental Obesogens: Mechanisms and Controversies

Abstract

Obesity is a worldwide pandemic in adults as well as children and adds greatly to health care costs through its association with type 2 diabetes, metabolic syndrome, cardiovascular disease, and cancers. The prevailing medical view of obesity is that it results from a simple imbalance between caloric intake and energy expenditure. However, numerous other factors are important in the etiology of obesity. The obesogen hypothesis proposes that environmental chemicals termed obesogens promote obesity by acting to increase adipocyte commitment, differentiation, and size by altering metabolic set points or altering the hormonal regulation of appetite and satiety. Many obesogens are endocrine disrupting chemicals that interfere with normal endocrine regulation. Endocrine disrupting obesogens are abundant in our environment, used in everyday products from food packaging to fungicides. In this review, we explore the evidence supporting the obesogen hypothesis, as well as the gaps in our knowledge that are currently preventing a complete understanding of the extent to which obesogens contribute to the obesity pandemic. Expected final online publication date for the Annual Review of Pharmacology and Toxicology Volume 59 is January 6, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Association of urinary polycyclic aromatic hydrocarbons and obesity in children aged 3–18: Canadian Health Measures Survey 2009–2015

“…These associations were independent of exposure to ETS and robust to control for a variety of covariates. The findings build upon previous work reporting associations between urinary PAH metabolites and obesity in children aged [6][7][8][9][10][11][12][13][14][15][16][17][18][19][19][20][21] and contribute to the literature highlighting young children as a population of concern. Childhood obesity is associated with increased risk of morbidity and mortality in adulthood from cardiovascular disease, hypertension, and type 2 diabetes and carries substantial societal and economic implications.…”

“…Thus associations observed in early childhood could possibly reflect effects of both prenatal and postnatal exposures. Multivariable linear regression association between waist circumference (cm) and quartiles of urinary levels of PAH metabolites, by age group, household population aged [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][2007][2008][2009][2010][2011][2012][2013][2014][2015]. Model-adjusted means and 95% confidence intervals are presented for each PAH quartile.…”

“…6 Although the rise in obesity rates has historically been thought to be largely driven by increased caloric intake and insufficient physical activity, there is mounting evidence that exposure to synthetic chemicals in our environment, called obesogens, plays an important role in the global obesity epidemic. 7 Moreover, studies suggest that exposures that occur during early life may have profound life-long impacts on body weight homeostasis. 8 To date, epidemiological studies have shown an association between exposure to environmental chemicals including pesticides, phthalates, flame retardants, bisphenol A, and polycyclic aromatic hydrocarbons (PAHs) and an increased risk of obesity.…”

Genome-wide association study of morbid obesity in Han Chinese

“…The involvement of epigenetic modifications in the development of obesity is becoming increasingly evident [56,57]. Obesity is associated with environmental pollutants (obesogens) [58], gut microbiota [59], and unbalanced food intake, all of which may result in weight gain, and altered metabolic consequences through epigenetic mechanisms. Further studies with a larger sample size are warranted to examine the interactions between genes and environmental factors, particularly dietary factors.…”

Bisphenol A enhances adipogenic signaling pathways in human mesenchymal stem cells

“…Endocrine disruptors possibly act as obesogens, by stimulating adipogenesis via promoting fat accumulation or developing a positive energy balance [6,7]. Endocrine disrupters can interfere with the endocrine system by mimicking or modifying the synthesis, transportation, metabolism, excretion or action of endogenous hormones [8,9].…”