The Centers for Disease Control and Prevention's biomonitoring studies, issued every two years, reports that incidences of testicular cancer, autism, attention deficit hyperactivity disorder, and male birth defects have all increased dramatically over the past few decades. Researchers are trying to learn if low levels of industrial chemicals might be responsible for these disturbing health trends.

Date:   8/26/2005 4:28:59 PM ( 19 y ago)

Over the past 30 years, the number of male babies born with hypospadias--a condition in which the urethra opens at the side rather than the end of the penis--has increased from a very rare condition to one affecting one in 250 boys. Another birth defect that has become more common recently is undescended testicles. Males with this condition are likely to develop low sperm counts and have an 11-fold increased risk of testicular cancer in early adulthood. The incidence of testicular cancer has doubled since the 1930's.

New research shows that declining male fertility has become a clear trend in the industrialized world. New studies of 19-year old men in Denmark, for example, show that about 25% have very low sperm counts--so low that they are considered essentially infertile. Sperm counts in the U.S. have declined, but not consistently across all regions.

Many researchers speculate that these male problems are caused by fetal exposure to environmental hormones--endocrine-disrupting chemicals that mimic or block the action of the human sex hormones estrogen and testrosterone. One study published in July shows a strong link between phthalate exposure in pregnant women and damage to their male babies' reproductive tracts. Phthalates are used in cosmetics and perfumes and as plasticizers in polyvinyl chloride products. Studies on rodents show that some phthalates block the action of testosterone.

Other chemicals suspected of disturbing the male reproductive tract are bisphenol A and polybrominataed diphenyl ethers (PBDEs) used as flame retardants, and perfluorooctanoic acids (PFOAs) use as surfactants in manufacturing DuPont's Teflon.

There are two other worrying trends. According to the CDC, reported cases of autism rose from one in 5,000 children in the late 1980's to one in 166 today. Some experts say thimerosal--the mercury-containing preservative that was used until recently in most childhood vaccines--may be responsible for the rising incidence. Others conclude there is little evidence linking thimerosal to autism.

And about one-third of the children in some schools now have asthma. Air pollution increases the number of severe asthmatic episodes that require emergency room treatment. But the primary cause for the escalating incidence of asthma is not known. Some studies show a link to phthalate or pesticide exposure.

CDC's biomonitoring studies alone will not give us answers to these medical mysteries, but they can provide a starting point. Substances that have declined sharply in blood and urine, such as dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin), mirex, dieldrin, and lead, though not completely off the hook, are probably not responsible for current disturbing trends. Other chemicals, however, appear in concentrations near thresholds of concern and should prompt further study.

One troubling finding in the recent survey is that about 5% of the population 20 years and older have cadmium levels in their urine that may be associated with kidney dysfunction.

Another disturbing discovery is that 5.7% of women have levels of mercury within a factor of 10 of what has been defined as the health threshold effect, which means that their levels fall between 5.8 and 58 ug/L. Mercury levels above 58 ug/L are associated with neurodevelopmental effects on the fetus. The current survey measures only total mercury, so it can not distinguish between the methylmercury from fish and the ethylmercury from thimerosal. The upcoming 2007 study will isolate the two forms of mercury.

To enable more rapid progress in discovering what is responsible for the disturbing medical trends, Congress should fully fund the National Children's Study. It is designed to correlate children's development from conception to age 21 with exposure to environmental chemicals. In fiscal 2004 and 2005, it was funded at only $12 million, when $26 million is needed annually.

For 2006, the organizers at the National Institutes of Health (NIH) have requested a total of $69 million to make up for the shortfalls in previous years and to implement the plans developed over several years. Only from such a thorough project as the children's study will researchers ever be able to learn if environmental exposures are the reasons for our health concerns.

Article summarized from "BIOMONITORING: CDC's surveys can be an important first step in demystifying medical trends."
by Bette Hileman
Chemical & Engineering News, August 15, 2005

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Toxins in Newborns: http://curezone.com/blogs/m.asp?f=309&i=98
Toxins in Cosmetics: http://curezone.com/blogs/m.asp?f=309&i=2
Toxins in Perfume: http://curezone.com/blogs/m.asp?f=309&i=65
Household "Products Cause Bad Air" http://curezone.com/blogs/m.asp?f=309&i=1
Pesticides: Body Burden: http://curezone.com/blogs/m.asp?f=309&i=61
Mercury/Autism Link: http://curezone.com/blogs/m.asp?f=309&i=66
Increased Male Mammaries, Decreased Sperm Count: http://curezone.com/blogs/m.asp?f=309&i=74

CALIFORNIANS: TAKE ACTION! Biomonitoring Bill http://curezone.com/blogs/m.asp?f=309&i=99




 

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