Environmental Levels of Phthalates Adversely Affect Male Reproductive Development

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May 27, 2005

Contact: Jim Tobin

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Environmental Levels of Phthalates Adversely Affect

Male Reproductive Development in Humans, Study Finds

Report in Environmental Health Perspectivessuggests

that exposure to a common class of chemicals poses

serious health concerns

[RESEARCH TRIANGLE PARK, NC] For the first time,

researchers have identified an association between

pregnant women's exposure to a nearly ubiquitous class

of chemicals known as phthalates and adverse effects

on genital development in their male children. The

findings, reported in a study published today in the

online edition of the peer-reviewed journal

Environmental Health Perspectives, are the first to

" support the hypothesis that prenatal phthalate

exposure at environmental levels can adversely affect

male reproductive development in humans, " the authors

write.

Most previous studies focusing on phthalate prenatal

exposure were in rodents. The current study analyzed

human exposure to phthalates, which are commonly used

in consumer products as solvents and to soften

plastics. Phthalates are also found in soft vinyl

plastic toys, medical tubing and fluid bags, and a

variety of cosmetics such as perfume, lotion, shampoo,

make-up, nail polish, and hairspray. Often, the

presence of these chemicals is not noted on labels. A

1999-2000 national study found that the majority of

the general population of the United States had

measurable exposure to multiple phthalates.

Researchers collected data from 85 eligible mother-son

pairs. All mothers had previously participated in a

multicenter pregnancy cohort study. Prenatal urine

samples were analyzed for the presence and quantity of

nine phthalate metabolites at the Division of

Laboratory Sciences, National Center for Environmental

Health, Centers for Disease Control and Prevention.

The 85 male children were examined for genital

characteristics that serve as markers of normal sexual

development. These measurements were then correlated

with the mothers' prenatal urinary phthalate levels.

The findings suggest that some phthalates have

antiandrogenic effects, meaning they may suppress the

hormones involved in male sexual development.

Higher levels of four phthalate metabolites

(mono-ethyl phthalate [MEP], mono-n-butyl phthalate

[MBP], mono-benzyl phthalate [MBzP], and mono-isobutyl

phthalate [MiBP]) were found to correlate with a

higher-than-expected number of abnormalities in

genital development including smaller anogenital

distance, scrotum, and penis, and an increased

likelihood of undescended testicles.

These findings were consistent with those from

previous rodent studies on phthalate exposure. " These

changes in humans associated with prenatal exposure to

some of the same phthalate metabolites that cause such

alterations in male rodents suggest that these widely

used phthalates may undervirilize humans as well as

rodents, " the authors write.

The study also noted that the median concentration of

phthalate metabolites associated with adverse male

genital development was below the levels found in one

in four women in the United States, based on a

nationwide sample.

The lead author of the study was Shanna H. Swan of the

University of Rochester, Department of Obstetrics and

Gynecology. Other authors included Katharina M. Main,

Fan Liu, Sara L. , Robin L. Kruse, Antonia M.

Calafat, S. Mao, J. Bruce Redmon,

L. Ternand, Sullivan, and J. Lynn Teague.

Funding sources for the research as reported by the

authors included the Environmental Protection Agency,

the National Institute of Environmental Health

Sciences, and the State of Iowa. The article is

available free of charge at

http://ehp.niehs.nih.gov/docs/2005/8100/abstract.html,

and will be published in an upcoming print edition of

the journal.

EHP is published by the NIEHS, part of the U.S.

Department of Health and Human Services. EHP is an

Open Access journal. More information is available

online at http://www.ehponline.org/. Brogan & Partners

Convergence Marketing handles marketing and public

relations for the publication, and is responsible for

creation and distribution of this press release.

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