Transcript People Safe: The Link Between Declining Fertility and Environmental Contaminants Amanda Bowes Reproductive Health Technologies Project Summer Intern Bryn Mawr College July 31, 2009

People Safe: The Link Between Declining
Fertility and Environmental
Contaminants
Amanda Bowes
Reproductive Health Technologies Project
Summer Intern
Bryn Mawr College
July 31, 2009
Contents
– Introduction:
– What is environmental health?
– The Chemical Connection
– How do we define fertility?
– Related health conditions for infertility
– Endocrine disruptors: an introduction
– Current Regulatory Framework - TSCA
– Proposed Regulatory Framework - KSCA
– Key chemical vocabulary
– A filter
– Male reproductive health:
– Low sperm count/decreased sperm quality
– Hypospadias
– Cryptorchidism
– Shortened/lengthened ano-genital distance
Contents
– Female reproductive health:
– Recurrent miscarriage/fetal loss
– Endometriosis
– Polycystic ovarian syndrome (PCOS)
– Conclusion:
– Discussion
– Recommendations – Research
– Recommendations – Industry
– Recommendations – Policy
– Acknowledgements
– Works Cited
Introduction
What is environmental health and justice?
– The “environmental health movement” dates at least to Progressive
Era urban reforms including clean water supply, more efficient
removal of raw sewage and reduction in crowded and unsanitary
living conditions. Today’s movement is more related to nutrition,
preventive medicine, aging well, etc..17
– “Environmental justice”, by contrast, began in the 1980s as an effort
to minimize the disparate impact of air pollution as well as water
and food chemical contamination on minority and poverty-stricken
populations.17
– Groups from both the environmental health and environmental
justice campaigns have emphasized chemical contaminants in our
environment and consumer products as a key concern.
The Chemical Connection
–
While chemical production has increased, human and
animal health has declined, particularly reproductive
health. The sudden and steep rates for physical and
behavioral sexual abnormalities suggests an environmental
component is at work.4
–
Although many of these chemicals have demonstrated a
negative effect on cancer incidence and various
developmental processes, I would like to focus on infertility
as a result of toxic chemical exposure.
How do we define infertility?
–
The Centers for Disease Control and Prevention defines
infertility as the inability to get pregnant after trying for one
year.
–
The CDC reports that in 2002, of the 62 million American
women of reproductive age, about 1.2 million, or 2%, had
an infertility-related medical appointment within the
previous year, and 8% had an infertility-related medical visit
at some point in the past.
–
7% of married couples in which the woman was of
reproductive age (2.1 million couples) were classified as
infertile according to the CDC definition.3
Infertility and related conditions
– There are various conditions that either directly or indirectly result
in infertility or reduced-fertility:
– Lower sperm count/decreased sperm quality
– Hypospadias
– Cryptorchidisms
– Shortened/lengthened ano-genital distance
– Recurrent miscarriage/Fetal loss
– Endometriosis
– Polycystic ovarian syndrome (PCOS)
Researchers cite exposure to endocrine disruptors as a possible cause
of these illnesses.
Endocrine Disruptors: an introduction
–
Endocrine disruptor is a term used to describe thousands of
chemicals that interfere with the endocrine system, or “an
integrated system of hormone-producing glands that
control various body functions”.6
–
Researchers point to endocrine disrupting chemicals, or
endocrine disruptors, as the cause for conditions such as
decreased sperm quality. Endocrine disruptors are present
in food, the environment, and consumer products.
–
Many endocrine disruptors affect not only the exposed
individual, but also his/her offspring and future
generations.6
Current Regulatory Framework
Toxic Substances Control Act (TSCA)
– TSCA was passed in 1976.
– TSCA holds the EPA solely responsible for demonstrating the
dangers of a particular chemical.1 Thus companies are not required
to prove the safety of the chemicals used in their products before
they are placed on the market.
– Without manufacturers’ data for the production and use of a
chemical, the EPA is often ill-equipped to effectively regulate a
potentially dangerous product.
– There has been a 30% increase in U.S. chemical production since
1979, with 80,000 chemicals now approved for commercial use,
many of which exhibit endocrine disrupting qualities.1
Proposed Federal Regulatory Frameworks
Kid-Safe Chemical Act (Kid-Safe)
– In January 2009, the Government Accountability Office placed
chemical safety to its “high risk list” of areas that should be addressed
immediately.1
– Kid-Safe was introduced in 2008 as an update/reform for TSCA.
Advocacy coalitions such as Safer Chemicals, Health Families would
like it to be reintroduced in 2009.
– Kid-Safe would require “pre-market testing” by companies and would
expand the list of chemicals researched and regulated by the FDA and
EPA.1
Other Chemical Specific Legislation
– Additionally, there has been federal chemical-specific regulation
proposed, including legislation introduced in March 2009 that would
remove bisphenol A from all food containers.
Key Chemical Vocabulary
Kid-Safe encourages the EPA and other agencies to regulate
chemical production using the following terms to describe the
risk a chemical poses to health:
– Persistence- how long the chemical remains in the
atmosphere or environment before being broken down. This
is measured by the chemical’s “half-life”, or “the interval
required for the quantity to decay to half of its initial value”.2
– Ubiquitous- the chemical or toxin is everywhere or at least in
many different elements of our environment.
– Bioaccumulative- a chemical or chemicals accumulate in an
organism. This occurs when an organism absorbs a toxic
substance at a rate greater than that at which the substance is
lost. 16
A filter
– For the purposes of my research and this presentation, I will
examine the relationship between individual or specific
groups of chemicals and these conditions.
– I have highlighted man-made contaminants specifically noted
in Kids-Safe to demonstrate the importance of passing this
piece of legislation.
– All of the substances described, including phthalates,
polychlorinated biphenyls, dioxins, bisphenol A,
diethylstilbestrol are considered endocrine disruptors.
Male Reproductive Health and
Infertility
Low sperm count/decreased sperm quality
–
Sperm counts in Western countries appear to have declined
by half in the past 50 years.4
–
In addition to lower sperm concentrations, DNA damage in
sperm contributes to poorer embryo development and
lower pregnancy rates among partners of men undergoing
assisted reproductive treatments.5
Phthalates
–
Phthalates are a family of endocrine disrupting chemicals
that are used in many consumer products to soften plastics,
from flooring and wall coverings, to medical devices and
personal-care products such as perfumes, lotions and
cosmetics.6 About a billion pounds of phthalates are
produced each year.1
Phthalates and semen quality
–
There are only a few epidemiological studies on phthalates
and semen quality. One large study from an infertility clinic
in Massachusetts found associations between monobutyl
phthalate (MBP) and decreased sperm motility and sperm
concentration.4
–
In a study by the Harvard School of Public Health, at least
90% of the male partners in a cohort of infertile couples
tested positive for MBP.5
–
Men exposed to DBP and/or DEHP (two other phthalates)
during puberty or adulthood experienced decreased sperm
production.5
PCBs
– Polychlorinated biphenyls (PCBs) are persistent compounds
that were widely used in industrial and consumer products for
decades until they were banned in the late 1970s.
– Used in cutting oils, lubricants, and electrical insulators.4
PCBs and semen quality
– In studies done in several different countries, including the
U.S., the evidence suggests an “inverse association of PCBs
with reduced semen quality, specifically reduced sperm
motility,” or the mobility of the sperm towards the egg.4
– Because the associations were found across a broad range of
PCB levels, there is believed to be no threshold of
exposure/vulnerability.4
– PCBs can also bioaccumulate up the food chain, so that fish,
meat, and dairy products we consume may increase our risk
of exposure.4
Dioxins
– Dioxins are a class of chemical contaminants that are formed
during combustion processes such as waste incineration,
forest fires, and backyard trash burning, as well as during some
industrial processes such as paper pulp bleaching and
herbicide manufacturing.7
Dioxins and semen quality
– Most exposure to dioxins (roughly 95%) occurs through eating
foods contaminated with these toxins. 7,1
– Recent studies suggest that the timing of exposure may have
an impact upon semen quality. Exposure at some ages may
result in decreased sperm count or sperm motility, whereas at
other ages there may be a stimulatory or increased effect.4
Hypospadias
– Hypospadias is a condition in which the opening to the
urethra (the tube through which urine and semen travel)
forms on the underside of the penis or below the penis.
– Hypospadias is the second most common birth defect in the
U.S.6 The Centers for Disease Control and Prevention (CDC)
reported a doubling of hypospadias cases from 1968 to 1993
in the U.S.. Rates are currently highest among whites and
lowest among Hispanics.8
– Reports of increased rates of hypospadias have coincided with
increased rates of testicular cancer, cryptorchidism, and
decreasing semen and sperm quality.8
Chemicals associated with hypospadias
– It is believed that phthalates could interfere with the ability of
testosterone to masculinize the male reproductive tract, resulting
in many different genital malformations including hypospadias.10
– Animals treated with either DBP or DEHP (phthalates) developed
hypospadias.9
– Diethylstilbestrol (DES), a chemical prescribed to pregnant women
as a means of preventing spontaneous abortions and promoting
fetal growth, instead caused women to give birth to daughters with
increased risk for breast, vaginal and cervical cancers, and
grandsons with a 20-fold increase in the development of
hypospadias.9
Cryptorchidism
– Cryptorchidism is a condition in which one or both of the
testes are missing from the scrotum at birth. This usually
suggests that the testes have failed to “descend” from the
abdominal area during fetal development.11
– Again, increased rates of cryptorchidism have coincided with
increased rates of testicular cancer, hypospadias, and
decreasing semen and sperm quality.8
Chemical contaminant exposure and cryptorchidism
– Studies show that the prevalence of cryptorchidism is variable
and geographically specific, with increasing trends in some
studies but not in others.4 The strongest data suggests that
people that either live in primarily agricultural areas or whose
parents were exposed to various nonorganochlorine
pesticides are at greater risk for cryptorchidism.
– Cryptorchidism has been observed following exposure to
DEHP and DBP (phthalates).9
Shortened/lengthened ano-genital distance
–
Ano-genital distance is the “measurement of the length of
the area between the anus and the genitals”6 and is usually
twice as large for males versus females.12
–
Because testosterone triggers this area to lengthen as a part
of normal male development, a shorter ano-genital distance
often suggests an interference with either the production
or action of testosterone.6
–
The condition is also associated with un-descended testes
and/or decreased sperm quality.
Bisphenol A
–
BPA is a chemical used in clear and shatter-proof plastic food
and drink containers, the lining of metal food and drink cans,
pacifiers and baby toys, computers, cell phones, paints,
adhesives, enamels and varnishes.6 Recent studies show
that BPA can migrate from the container into the contents,
especially when heated.10 About 6 billion pounds of BPA are
produced each year.1
The Trouble with BPA
–
In a 2003-2004 bio-monitoring study by the Centers for
Disease Control, 92.6% of over 2500 Americans had BPA in
their urine.4,1
–
BPA has a longer half-life in humans than previously
thought.4
–
Also, BPA appears to have an unusual dose-effect, showing
an inverted-U dose-response curve.14
Bisphenol A and ano-genital distance
–
Bisphenol A (BPA) has been shown to increase ano-genital
distance in a study of rats.6
–
Although the FDA currently describes BPA as “safe”, Canada
and many U.S. states and cities have banned the chemical.
According to Heather Patisaul and Heather Adewale, the
“fate of BPA may ultimately be decided by politics and
public perception, rather than a regulatory action based on
a measured evaluation of the scientific evidence”.10
Female Reproductive Health and
Infertility
Recurrent miscarriage/fetal loss
–
The number of miscarriages and stillbirths have increased
from 14 per 1,000 pregnancies during the 1980s to 16 per
1,000 in the 1990s and 2000s.1
–
About 40-70% of miscarriages are linked to chromosomal
abnormalities at conception, i.e. unusual numbers of
individual or entire sets of chromosomes.13
–
Adult humans exposed to dioxins, PCBs, heavy metals such
as lead, mercury and cadmium, and various phthalates
have demonstrated fetal loss.12
BPA and recurrent miscarriage/fetal loss
–
According to recent Japanese study, high in vivo (or after a
person is born) exposure to BPA may be associated with
recurrent miscarriage.
–
Because measurable amounts of BPA have been found in
the amniotic fluid and placental tissue of pregnant
women, it is believed that developing fetuses are readily
exposed to this chemical.4
Endometriosis
– Endometriosis is a chronic disease in which women develop
tissue that usually lines the uterus grows abnormally in other
locations, such as the ovaries and fallopian tubes, and even in
distant organs like the lungs and heart.12
– About 40% of women diagnosed with endometriosis also
suffer from infertility.12
– In 2002, the total health care costs in the U.S. for diagnosis
and treatment of endometriosis was approximately $22
billion.4
Chemicals associated with endometriosis
– Elevated serum levels of dioxin-like compounds such as PCBs
correlated strongly with endometriosis.14
– Rhesus monkeys treated with TCDD developed acute
endometriosis and women with endometriosis also had high
plasma concentrations of phthalates in a study in India.4
– In an Italian study, a similar association between plasma
concentrations of phthalates such as DEHP and endometriosis
was found.14
Polycystic ovarian syndrome (PCOS)
– Polycystic ovarian syndrome or PCOS can affect a woman's
menstrual cycle, ability to have children, hormones, heart,
blood vessels, and appearance. Women with PCOS have high
level of androgens (a typically male hormone), missed or
irregular periods, and many small cysts in their ovaries.15
– The Endocrine Society describes PCOS as a “leading cause of
subfertility”.4
– The cost to the health care system for PCOS diagnosis and
treatment totals $4.4 billion in the U.S. in 2004.4
PCOS and BPA
–
Women with PCOS also have higher levels of BPA.4
–
A 5-fold higher level of BPA in the amniotic fluid of mothers
of PCOS patients suggests prenatal exposure.4
Conclusions
Discussion
–
Many of the chemicals included in the Kid-Safe legislation
have a demonstrated and significant impact on humans’
reproductive health, particularly on their fertility.
–
Although we must consider the current research, more can
and should be done to fully understand the biological threat
these contaminants pose.
–
It is critical that government officials, advocates, and
manufacturers work to bring consumers’ expectations and
a product’s reality with regard to long-term use and safety
in synch by strengthening current chemical regulation.
Recommendations - Research
–
Because individuals or populations are constantly exposed
to multiple industrial chemicals, it can be difficult to
establish the effects of one compound at a time. Thus
more research should be conducted to explore the effects
of a combination of BPA and certain phthalates, for
example.
–
Research on possible “green” or safe alternatives must be a
priority. Current funding for green chemistry research
represents a very small portion of the federal budget.1
Recommendations – Industry
– Manufacturers must be required to provide the EPA and the
public with basic information with regard to a chemical’s
safety for consumers and workers.
– The chemical industry should be held responsible for
demonstrating their product’s safety, similar to
pharmaceuticals which are subject to stringent pre-market
testing. Such chemical safety data must be published and
disseminated to the wider public.
– Corporations should be encouraged to research “green” or
non-harmful alternative chemicals to be used in production.
Recommendations – Policy
– Rep. Ed Markey (D-MA) and Sens. Dianne Feinstein (D-CA) and
Chuck Schumer (D-NY) introduced legislation to ban BPA in all
food and beverage containers in March 2009.1 Similar
chemical-specific regulation and overall chemical regulation
reform is needed.
– The EPA should coordinate more effectively with FDA and
other agencies to reduce the amounts of persistent, bioaccumulative toxicants (PBTs) in our environment and
consumer products.
– More resources and authority should be given to the FDA and
CPSC to protect us from harmful chemicals in cosmetics and
consumer products.
Acknowledgements
Invaluable input and feedback were provided by the entire
Reproductive Health Technologies Project staff, especially
Jenn Rogers, acting director, and Lydia Stuckey, my
“supervisor” for the summer.
I would also like to thank Bryn Mawr College’s Katharine
Houghton Hepburn Center and Susan Wood, PhD for the
opportunity to work with such an amazing organization these
past eight weeks.
Works Cited
1
Rushing, Reece. Center for American Progress. “Reproductive Roulette: Declining Reproductive Health,
Dangerous Chemicals, and a New Way Forward”. July 2009.
2 “Half-life”. Wikipedia article. http://en.wikipedia.org/wiki/Half-life. July 20, 2009.
3 Assisted Reproductive Technology, Home. Centers for Disease Control and Prevention, Department of Health
and Human Services. http://www.cdc.gov/ART/. July 20, 2009.
4 Diamanti-Kandarakis, Evanthia, et al., the Endocrine Society. Endocrine-Disrupting Chemicals: An Endocrine
Society Scientific Statement. 2009.
5 Hauser, R., et al. “DNA damage in human sperm is related to urinary levels of phthalate monoester and
oxidative metabolites”. Human Reproduction Vol. 22, No. 3, pp. 688-695. 2007.
6 Schwartz, Jackie M. et al. Shaping Our Legacy: Reproductive Health and the Environment. University of
California San Francisco, Program on Reproductive Health and the Environment.
7 “Dioxins”. National Institute of Environmental Health Sciences, National Institutes of Health.
http://www.niehs.nih.gov/health/topics/agents/dioxins/index.cfm. July 22, 2009.
8 Wang, Ming-Hsien et al. “Endocrine Disruptors, Genital Development, and Hypospadias”. Journal of
Andrology, Vol. 29, No. 5. September/October 2008.
9 David, Raymond M. “Proposed Mode of Action for In Utero Effects of Some Phthalate Esters on the
Developing Male Reproductive Tract”. Toxicologic Pathology, 34. pp. 209-219. 2006.
10 Patisaul, Heather B. and Adewale, Heather B. “Long-term effects of environmental endocrine disruptors on
reproductive physiology and behavior”. Fronteirs in Behavioral Neuroscience, Vol. 3, Article 10. pp. 1-18.
June 2009.
Works Cited Continued
11
“Cryptorchidism”. Wikipedia article. http://en.wikipedia.org/wiki/Cryptorchidism. July 23, 2009.
12 Luoma, Jon. Challenged Conceptions: Environmental Chemicals and Fertility. Stanford University School of
Medicine, Collaborative on Health and the Environment. October, 2005.
13 Sugiura-Ogasawara, Mayumi et al. “Exposure to bisphenol A is associated with recurrent miscarriage”.
Human Reproduction, Vol. 20, No. 8. pp. 2325-2329. 2005.
14 Caserta, D. et al. “Impact of endocrine disruptor chemicals in gynaecology”. Human Reproduction Update,
Vol. 14, No. 1. pp. 59-72. 2008.
15 Savabieasfahani, Mozhgan et al. “Developmental Programming: Differential Effects of Prenatal Exposure to
Bisphenol-A or Methoxychlor on Reproductive Function”. Endocrinoogy, Vol. 12, No. 147. pp. 5956-5966.
2006.
16 “Bioaccumulation”. Wikipedia article. http://en.wikipedia.org/wiki/Bioaccumulation. July 30, 2009.
17 “Environmental movement in the United States”. Wikipedia article.
http://en.wikipedia.org/wiki/Environmental_movement_in_the_United_States. July 30, 2009.
www.rhtp.org