PHTHALATE FEARS: The boys' birth defect hypospadias may not be on the rise, calling into question dangers posed phthalates and other endocrine disruptors.
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Hypospadias, one of the most common birth defects among baby boys, apparently is not increasing in the U.S., casting doubt on whether boys are harmed by phthalates and other endocrine-disrupting chemicals thought to trigger reproductive abnormalities.
Researchers have reported that the hypospadias rate stayed the same in New York State between 1992 and 2005. An earlier study also found no increase in California boys between 1984 and 1997.
Hypospadias, a condition in which the urethra opening is on the underside of the penis rather than the tip, occurs in roughly one of every 250 male births. Surgery is normally required or the condition can lead to infertility.
Some environmental scientists have suspected, based on studies of lab animals, that exposure to chemicals that block testosterone may be partially responsible for the birth defects.
In tests of lab rats, chemicals called phthalates, which are widely used in plastic and personal care products, cause several reproductive abnormalities that scientists have dubbed “testicular dysgenesis syndrome" or "phthalate syndrome." Included are hypospadias, undescended testes, reduced sperm counts and testicular cancer.
In the new study, New York Presbyterian Hospital urologists said that because hypospadias rates are stable, it casts doubt on whether human boys are harmed by phthalates or other endocrine-disrupting chemicals.
The researchers reported in the journal Urology that “these data suggest that the testicular dysgenesis syndrome described in animal models may not be evident in humans.” The lead author was Dr. Harry Fisch, director of the hospital’s Male Reproductive Center and a professor of clinical urology at Columbia University.
But other experts say the study does not invalidate the theory.
“The evidence seems to suggest that there hasn't been a big increase in hypospadias over recent years, which does weaken the argument that new endocrine disruptors in the environment are causing hypospadias,” said Kim Harley, a University of California, Berkeley epidemiologist who studies environmental exposures and human health but was not involved with the study.
Nevertheless, she added that it doesn’t rule out that phthalates or other chemicals have a role in causing the defects. Looking at how birth defect rates change over time is not an adequate way of examining environmental connections.
“Hypothetically, what if there were something that we were exposed to in the past that also was associated with hypospadias? If that other exposure were decreasing at the same time as phthalates were increasing, it might wash out the effect and make rates stable over time,” Harley said. “That is why a study like this can only hypothesize based on time trends, but can’t make a one-to-one link between a chemical and a disease.”
Russ Hauser, a Harvard School of Public Health professor of environmental and occupational epidemiology who studies phthalates and other endocrine-disrupting chemicals, agreed. “There are many reasons for why hypospadias may or may not have changed over time. Other risk factors also change over time," he said.
The cause of hypospadias is unknown, but medical experts suspect that something in the womb disrupts genes that regulate male hormones. A variety of factors, including the mother’s age, could be to blame. The New York study found that hypospadias is more common in boys born to mothers 35 years or older.
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9 Comments
Add CommentAnother unfounded alarmist theory shot down. Add it to the pile:
Reply | Report Abuse | Link to thisAlar
Acid rain
DDT
Breast Implants
Radiated Food
GM Foods
Landfill space shortages
Hey, SoccerDad, don't add it to the pile yet. One result does not a consensus make!
Reply | Report Abuse | Link to thisIt would be great if more research confirms that phthalates are not as dangerous as feared. But your tone almost suggests we should never worry about anything, it is all "alarmism". But there are clearly some man made problems that are very real. Minamata disease is a classic example. Or tobacco. Or all the radium poisonings back when radiation was fashionable.
There is always a difficult balance between caution and not damaging existing businesses, etc. But you only know what were false fears after the necessary research has been done. You can't just dismiss every possible danger as "unfounded alarmism".
The sad thing is that some of these continue to be problems in the popular imagination even after the science has pretty conclusively shown them not to be problems (e.g. vaccines and autism, mobile phones, Wi-Fi, ...)
Incidentally, it is not my area of expertise, but I suspect that acid rain is one of the things (like the millennium bug or SARS) that were real problems but were tackled succesfully and so appear to have been exaggerated.
the fact that this disorder is no more common now than it was in 1992 (when plastics had not yet been invented) is indisputable proof that there is no link between these chemicals and medical problems. we should continue exposing our children to them. the controlled experiments that show these chemicals cause problems in animals are obviously part of a communist conspiracy to destroy america. anyone who disagrees is an alarmist paranoid lunatic.
Reply | Report Abuse | Link to thisTino,
Reply | Report Abuse | Link to thisThe dose makes the poison. The fact these chemicals may cause problems in animals only proves they cause problems in animals at a specific dose. Period.
Tino, "plastics had not been invented" in 1992? Where have you been?
Reply | Report Abuse | Link to thiscool...
Reply | Report Abuse | Link to thisbut not coolll
Plastics were invented before 1992: they were mass produced as a replacement for rubber soles in soldier's boots when Japan seized The U.S.'s rubber supply in the forests of SE Asia during the 2nd World War. And I thought the Red Scare faded after the USSR's collapse.
Reply | Report Abuse | Link to thisBut the downside to America is that a chemical has to be proven to be dangerous for the U.S. to ban it's commercial use, whereas in the E.U., a chemical has to be proven to be safe before it is allowed.
Its true.There is always a difficult balance between caution and not true aging existing businesses, etc.
Reply | Report Abuse | Link to thisThanks for sharing..
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Tino,
Reply | Report Abuse | Link to thisI presumed you were kidding. What you said looked more like satire than your true opinion. But, others seem to have taken you seriously. Which is it?