{"id":1722,"date":"2012-02-10T09:12:57","date_gmt":"2012-02-10T14:12:57","guid":{"rendered":"http:\/\/blogs.edf.org\/nanotechnology\/?p=1722"},"modified":"2026-03-16T15:21:04","modified_gmt":"2026-03-16T20:21:04","slug":"linking-everyday-chemicals-to-disease-new-science-keeps-on-intensifying-the-writing-on-the-wall","status":"publish","type":"post","link":"https:\/\/blogs.edf.org\/health\/2012\/02\/10\/linking-everyday-chemicals-to-disease-new-science-keeps-on-intensifying-the-writing-on-the-wall\/","title":{"rendered":"Linking everyday chemicals to disease: New science keeps on intensifying the writing on the wall"},"content":{"rendered":"<p><em>Richard Denison, Ph.D.<\/em><em>, is a Senior Scientist.<\/em><\/p>\n<p>As a Washington policy geek, it\u2019s sometimes hard not to let the ups and downs of political prospects for achieving real improvements in public health protections from toxic chemicals get me down.\u00a0 The tenacity with which some stakeholders insist on throwing wrenches into the works to block efforts to reach middle ground is indeed depressing.<\/p>\n<p>But through it all, there is one constant that continually restores my optimism that we\u2019ll eventually get where we need to get to:\u00a0 Science keeps moving forward and inexorably points toward the need for reform.\u00a0 I will use this post to briefly highlight four recent studies that demonstrate the changing landscape of our knowledge of how environmental factors, including toxic chemical exposures, are affecting our health.\u00a0 What\u2019s noteworthy about these studies is that they all identified adverse health effects in <em>human populations<\/em>, and linked those effects to early-life exposures.\u00a0 They all also illustrate the complex interplay between chemical exposures and social or other environmental factors that directly challenges the overly simplistic and non-scientific approach to causation that our chemicals policies have taken for decades.<\/p>\n<p>Below are summaries of and links to these new studies:<\/p>\n<ul>\n<li><strong><em>Early-life exposure to PCE is associated with later-life risky behaviors<\/em><\/strong>.<\/li>\n<li><strong><em>Phthalate exposure is associated with excess weight in New York City children<\/em><\/strong>.<\/li>\n<li><strong><em>Exposure to perfluorinated chemicals may interfere with childhood vaccine effectiveness<\/em><\/strong>.<\/li>\n<li><strong><em>Epigenetic changes are associated with socio-economic status and biomarkers for cardiovascular disease.<\/em><\/strong><\/li>\n<\/ul>\n<p><strong><em><!--more--><\/em><\/strong><\/p>\n<p>Here are the summaries:<\/p>\n<ul>\n<li><strong><em>Early-life exposure to PCE is associated with later-life risky behaviors<\/em><\/strong>.<\/li>\n<\/ul>\n<p style=\"padding-left: 30px;\">It is well-established that acute and chronic exposures to solvents like perchloroethylene (PCE) can affect one\u2019s cognitive abilities as well as mental disposition and behavior.\u00a0 So it should probably not come as a great surprise that epidemiologists are finding links between such exposures and problematic social behaviors such as alcohol and drug abuse and smoking.<\/p>\n<p style=\"padding-left: 30px;\">A <a href=\"http:\/\/www.ehjournal.net\/content\/pdf\/1476-069X-10-102.pdf\">major new retrospective cohort study (Aschengrau et al. 2011)<\/a> published in <em>Environmental Health<\/em> compared a group of more than 800 people who had been exposed either prenatally or in early childhood to PCE in contaminated drinking water to an unexposed group of more than 500 people.\u00a0 These researchers at Boston University School of Public Health found a 50-60% increase in the extent of drug use as teenagers or adults in those individuals who were highly exposed to PCE early in life, and a 30-60% increase in risky drinking and smoking behaviors.\u00a0 The study employed extensive statistical analysis to identify and control for many other potentially confounding factors, including the subjects\u2019 mothers\u2019 behaviors and health status and a history of learning disabilities or mental illness.\u00a0 While the authors appropriately note that \u201cThese findings should be confirmed in follow-up investigations of other exposed populations,\u201d this study ought to be a real wake-up call.<\/p>\n<ul>\n<li><strong><em>Phthalate exposure is associated with excess weight in New York City children<\/em><\/strong>.<\/li>\n<\/ul>\n<p style=\"padding-left: 30px;\">We\u2019ve <a href=\"http:\/\/blogs.edf.org\/nanotechnology\/?s=obesity\">blogged here before<\/a> about the increasing evidence that certain chemicals may act as \u201cobesogens,\u201d in some cases interacting with dietary, lifestyle and other environmental factors to increase the proclivity toward obesity.\u00a0 Of particular concern are studies in laboratory animals that indicate prenatal and early-life exposures to such chemicals appear to increase life-long susceptibility.<\/p>\n<p style=\"padding-left: 30px;\">A <a href=\"https:\/\/sciencedirect.com\/science\/article\/pii\/S0013935111003112\" target=\"_blank\" rel=\"noopener\">new study (Teitelbaum et al., 2011)<\/a> just published in <em>Environmental Research<\/em> lends greater weight to these findings.\u00a0 The authors, who work at the Centers for Disease Control and at Mt. Sinai School of Medicine, measured body mass index (BMI) and weight circumference of 387 Hispanic and Black New York City children who were between six and eight years old.\u00a0 They also measured the concentrations in the children\u2019s urine of nine breakdown products (\u201cmetabolites\u201d) of phthalates, including both high- and low-molecular-weight phthalates.\u00a0 Of these, the urinary concentration of one of the metabolites \u2013 that of monoethyl phthalate \u2013 as well as the sum of all of the low-molecular-weight phthalate metabolites showed a strong dose-response relationship with both measures of body size in overweight children among the cohort. While such associative studies do not prove causality, the results are wholly consistent with other laboratory animal and human epidemiological studies.\u00a0 All of this research increasingly points to the <a href=\"http:\/\/en.wikipedia.org\/wiki\/Antiandrogen\">anti-androgenic effects<\/a> of certain phthalates as the biological basis for physiological changes leading to increased body size (among other effects such as interference with normal reproductive development).<\/p>\n<ul>\n<li><strong><em>Exposure to perfluorinated chemicals may interfere with childhood vaccine effectiveness<\/em><\/strong>.<\/li>\n<\/ul>\n<p style=\"padding-left: 30px;\">Perfluorinated chemicals (PFCs) are widely used as surfactants and as water, grease and stain repellants in everything from upholstery textiles and clothing to paper food packaging.\u00a0 As a class they are environmentally persistent and in some cases bioaccumulative, which has led to contamination of water and food.\u00a0 Two of the most infamous PFCs are perfluorooctanoic acid (PFOA, <a href=\"http:\/\/www.epa.gov\/oppt\/pfoa\/\">now being phased out<\/a>), the basis for the Teflon brand of products; and perfluorooctane sulfonic acid (PFOS), the <a href=\"http:\/\/yosemite.epa.gov\/opa\/admpress.nsf\/0\/33aa946e6cb11f35852568e1005246b4\">former basis<\/a> for the Scotchgard brand of products.\u00a0 Both chemicals have been routinely detected in people through biomonitoring.<\/p>\n<p style=\"padding-left: 30px;\">A <a href=\"http:\/\/jama.ama-assn.org\/content\/307\/4\/391.short\">new study (Grandjean et al., 2012)<\/a> just published in the <em>Journal of the American Medical Association<\/em> followed a group of about 600 babies born in the Faroe Islands (part of Denmark) through early childhood.\u00a0 This location was selected because a high fish diet was expected to lead to higher levels of PFC exposure.\u00a0 The children had received routine tetanus and diphtheria vaccines, and then at 5 and 7 years old were tested for associated antibody levels, which are correlated with the ability to fight off the disease if a child becomes infected.\u00a0 The study found that the level of PFCs in the children\u2019s blood was inversely correlated with the level of antibodies produced and maintained in response to the two vaccines:\u00a0 the higher the levels of PFCs, the lower the antibody count.\u00a0 In addition, the expectation that these children would carry higher levels of PFCs in their bodies due to higher fish consumption was not borne out; their levels were the same as or even slightly lower than those of children living in the U.S.<\/p>\n<ul>\n<li><strong><em>Epigenetic changes are associated with socio-economic status and biomarkers for cardiovascular disease<\/em><\/strong>.<\/li>\n<\/ul>\n<p style=\"padding-left: 30px;\">A growing body of research is identifying changes in epigenetic patterns in our DNA as a key mechanism that mediates the effects of exposure to a wide array of environmental factors, leading to changes in gene expression.\u00a0 We\u2019ve <a href=\"http:\/\/blogs.edf.org\/nanotechnology\/2011\/04\/20\/could-these-chemicals-make-my-grandchild-look-fat\/\">blogged here before<\/a> about evidence suggesting that such epigenetic perturbations may explain how early-life exposures to toxic chemicals can lead to adverse health outcomes later in life.<\/p>\n<p style=\"padding-left: 30px;\">Now, a <a href=\"http:\/\/ije.oxfordjournals.org\/content\/early\/2012\/01\/25\/ije.dyr215.short?rss=1\">new study (McGuinness et al., 2012)<\/a> from British researchers published in the <em>International Journal of Epidemiology<\/em> adds to evidence that socio-economic status can lead to alterations in epigenetic programming that are in turn tied to potential adverse health outcomes.\u00a0 In this study, a key type of epigenetic marking \u2013 methylation of DNA \u2013 was measured in about 240 people in Glasgow, Scotland.\u00a0 What was measured was not the methylation of specific genes but rather the total level of methylation of DNA (termed global DNA methylation).\u00a0 The authors note that \u201cChanges in global DNA methylation may be some of the earliest cellular events in disease onset,\u201d citing evidence linking decreases in DNA methylation to aging as well as various diseases, including cardiovascular and neuronal disorders and cancer.\u00a0 The Glasgow cohort used in the study was established originally to investigate \u201cthe associated variation in mortality, morbidity and the extreme socio-economic (SE) gradient of health inequality in this city which is not fully explained by conventional risk factors for disease.\u201d\u00a0 What the authors found is startling:\u00a0 A 17% reduction in global DNA methylation in the most socio-economically deprived group within the cohort compared with the least deprived group, and a 24% decrease in manual workers compared to non-manual workers that could not be explained by differences in age, gender or other factors beyond income level.\u00a0 These reductions also correlated with an increase in certain biomarkers of cardiovascular disease, indicating higher risk.<\/p>\n<p style=\"padding-left: 30px;\">The authors note that \u201cSuch global hypomethylation could be reflective of environmental exposures and\/or diet during life, or a direct consequence of developmental programming <em>in utero<\/em>, or a combination of both.\u201d \u00a0While noting that a larger study would be needed to distinguish among these options, they note that <em>in utero<\/em> epigenetic reprogramming has been associated in other studies with development of obesity, arteriosclerosis and diabetes.\u00a0 In any event, it should be very disturbing that low socio-economic status has now been shown to lead to readily measurable epigenetic changes associated with adverse health outcomes, potentially not only in individuals directly exposed but also in their children.<\/p>\n<p>So there you have it:\u00a0 Four studies that happened to come across my desk over just the last couple of weeks.\u00a0 While no single such study is ever definitive, the results support and add to the import of many other studies in both laboratory animals and people.\u00a0 Taken together, this growing body of research simply <em>must<\/em> move us to re-examine the impacts on our health arising from our shockingly laissez-faire approach to environmental exposures, especially those that disproportionately affect the most vulnerable among us.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Richard Denison, Ph.D., is a Senior Scientist. As a Washington policy geek, it\u2019s sometimes hard not to let the ups and downs of political prospects for achieving real improvements in public health protections from toxic chemicals get me down.\u00a0 The tenacity with which some stakeholders insist on throwing wrenches into the works to block efforts &#8230;<\/p>\n","protected":false},"author":100,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[56100,5009],"tags":[39168,25093,39208,39986,39174,39176,39163,39175],"coauthors":[],"class_list":["post-1722","post","type-post","status-publish","format-standard","hentry","category-emerging-science","category-health-science","tag-biomonitoring","tag-contamination","tag-methylation","tag-endocrine-disruption","tag-epigenetics","tag-obesity","tag-phthalates","tag-prenatal"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/1722","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/users\/100"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/comments?post=1722"}],"version-history":[{"count":2,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/1722\/revisions"}],"predecessor-version":[{"id":13648,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/1722\/revisions\/13648"}],"wp:attachment":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/media?parent=1722"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/categories?post=1722"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/tags?post=1722"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/coauthors?post=1722"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}