Scientists urge action against prenatal and early infancy exposures

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Posted by Sharon Kramer

Environmental Science and Technology, June 27, 2007

A scientific consensus statement targets pervasive chemicals.

" Public-health officials are concerned about early exposures, even at very

low concentrations, to certain chemicals that might be linked to major health

problems later in life. These afflictions include cancer; diabetes; obesity;

and impaired immune, reproductive, cardiovascular, neurological, endocrine,

and respiratory systems. "

Faced with a cumulative body of evidence that links serious health problems

with prenatal and early infancy exposures to various chemicals, an

international assembly of scientists, doctors, and researchers says it’s time

to take

action.

The public proclamation came at the end of a conference held May 20–24 in

the Faroe Islands located in northern Europe between the Norwegian Sea and the

North Atlantic Ocean. The multidisciplinary support of the _“Faroes

Statementâ€

_ (http://www.pptox.dk/Consensus/tabid/72/Default.aspx) from nearly 200

people from five continents—including toxicologists, biologists, chemists,

epidemiologists, nutritionists, pediatricians, and environmental health

specialists—

adds considerable weight to several decades of diverse science on the effect

of pollutants at these early stages of development.

Dolinoy et al.

Fetal exposure of mice to nutrient supplements (genistein or various

combinations of vitamin B12, folic acid, choline, and betaine) contributed to

epigenetically induced changes, such as obesity in the larger mice and variable

fur

color. Image from Dolinoy et al. (Environ. Health Perspect. 2006, 114 [4],

_567–572_ (http://www.ehponline.org/members/2006/8700/8700.html) ).

The statement refers to the growing number of substances that affect

developing embryos and infants, including the pesticides DDT, atrazine,

methoxychlor, and vinclozolin. Other suspects include the plastics and epoxy

resin

ingredient bisphenol A, plasticizing agents called phthalates, and the drug

diethylstilbestrol, once used to prevent miscarriages and other pregnancy

problems,

as well as mercury, lead, arsenic, organotins, PCBs, carbon monoxide, fine

particulates, tobacco smoke, and alcohol.

“Until now, it’s been difficult to know if there’s a consensus on the

issue,

†says Bruce Lanphear, a pediatrics professor at Cincinnati Children’s

Hospital Medical Center who attended the conference.

The declaration highlights the results of many studies of humans, laboratory

animals, or both. Public-health officials are concerned about early

exposures, even at very low concentrations, to certain chemicals that might be

linked

to major health problems later in life. These afflictions include cancer;

diabetes; obesity; and impaired immune, reproductive, cardiovascular,

neurological, endocrine, and respiratory systems.

The statement also shines a light on the relatively new field of

epigenetics, which finds that numerous heritable changes occur through

alterations of a

gene’s function and not just changes in its structure. Research in

epigenetics by Skinner, director of the Center for Reproductive Biology

at

Washington State University, and his colleagues has found that disorders—for

example, breast tumors, kidney disease, and immune abnormalities—caused by

prenatal exposure in rats to the fungicide vinclozolin can extend through at

least

four generations even without direct exposure to the fungicide by subsequent

generations (Endocrinology 2006, 147 [12], _5515–5523_

(http://endo.endojournals.org/cgi/content/abstract/147/12/5515) ; _5524–5541_

(http://endo.endojournals.org/cgi/content/abstract/147/12/5524) ).

Skinner and his team have also found in a published study (Proc. Natl. Acad.

Sci. U.S.A. 2007, 104 [14], _5942–5946_

(http://www.pnas.org/cgi/content/abstract/104/14/5942?maxtoshow= & HITS=10 & hits=10\

& RESULTFORMAT= & fulltext=vinclozolin

& searchid=1 & FIRSTINDEX=0 & resourcetype=HWCIT) ) that females at least three

generations removed from the brief initial exposure preferred males who were

not exposed, suggesting implications for mate selection and evolution.

The declaration calls for governments to make changes in policies and

regulations to help prevent exposures; improve and expand baseline testing to

assess human exposures and environmental occurrences; and conduct more research

on

topics such as disease processes, mechanisms, exposure timing, effects of

chemical mixtures, and nonchemical influences, such as socioeconomic factors.

The statement was developed by a 28-person international committee before

the conference, but it wasn’t officially signed by any group. Still, the

sponsors of the meeting included the World Health Organization (WHO); the

European

Environment Agency; the U.S. Centers for Disease Control and Prevention

(CDC); and the National Institutes of Health and two of its members, the

National

Institute of Environmental Health Sciences (NIEHS) and the National Institute

of Child Health and Human Development (NICHD).

WHO already has begun to circulate the declaration among organizations it

works with, says Philippe Grandjean, co-chair of the conference, who holds

positions at the University of Southern Denmark and the Harvard School of

Public

Health.

The architects of the _U.S. National Children’s Study_

(http://www.nationalchildrensstudy.gov/) (NCS) say they will consider the

statement. The study,

scheduled to begin in mid-2008 and funded by NICHD, NIEHS, CDC, and the U.S.

EPA, is being designed to provide long-term and case-control studies of 100,000

children from preconception to age 21 for a wide range of health issues.

Keim, NCS coordinator, says, “We will always update our plans to reflect

the latest thinking and hope to answer a lot of the questions that were raised.

â€

Yet, incorporating the information addressed by the proclamation into

policies and regulations is likely to be a slow, incremental process, Lanphear

says. In Europe, new chemical regulations known as REACH (the Registration,

Evaluation, and Authorisation of Chemicals), which went into effect on June 1,

address prenatal and early infancy exposures in only a limited way, Grandjean

says. However, he says it’s possible that the European Parliament may

consider

this issue as it works through its reauthorization of pesticides.

The final statement is expected to be posted on the website of the journal

_Basic & Clinical Pharmacology & Toxicology_

(http://www.blackwell-synergy.com/loi/pto) by late June, Grandjean says.

—ROBERT WEINHOLD

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