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Rodent study scares on endocrine disruptors do not pan out for humans

In what is surely disappointing news to researchers like Shanna Swan and Fred vom Saal, who have been capitalizing on the exaggerated fears of synthetic endocrine disruptors for years, an article just published in the Journal of Urology does the epi study, and can't find any effect. [Hypospadias rates in New York State are not increasing—J Urol. 2009 May;181(5):2291-4. Epub 2009 Mar 19]

Swan, vom Saal, and others have posited terrible urogenital consequences, based on in utero exposure of various chemicals in rodents. As has been well established, though, rodents are not humans. Therefore, any rodent results need to be looked at in a good human epidemiological study. And, that's just what Harry Fisch et al. did.

Yes, real scientists looking at real data on real humans have just blown in big hole in the "scientific" basis for the absurd bans of certain phthalates and BPA.

The rodent disruptor crew speaks of urogenital abnormalities associated with exposure to environmental endocrine disruptors such as phthalates:  Namely, decreased semen quality, increased rates of testis cancer, and hypospadias.

Hypospadias is a developmental anomaly characterized by a defect on the ventrum of the penis whereby the urethral meatus is more proximal than its normal glandular location. In essence, it means that the urinary opening is too low. The team picked hypospadias because there is lots of data on this condition.

To determine if hypospadias rates are increasing, the researchers retrospectively reviewed the total prevalence of hypospadias in New York State from 1992 to 2005, categorized by maternal age younger than 35 years and 35 years or older.

Their conclusions? Hypospadias rates have not changed in New York State from 1992 to 2005. Additionally, advanced maternal age continues to be a risk factor for hypospadias. Combined with previous studies that demonstrate sperm counts are not declining, these data suggest that the testicular dysgenesis syndrome described in animal models may not be evident in humans.

Bear in mind that there are plenty of naturally-occurring endocrine disruptors in food (phytoestrogens), and some data (from North and Golding) actually suggest that a vegetarian diet in pregnancy could adversely affect the developing male reproductive system. Vegetarians would tend to consume more phytoestrogens and pesticides. Soy, for example, contains the potent phytoestrogen genistein. Balance this, though, with the fact that genistein has several health benefits.

  • It is a potent antioxidant
  • It is protective against osteoporosis
  • It seems to reduce the risk for some hormone related cancers, principally breast cancer and prostate cancer

Wow! This is enough to make your head explode! Endocrine disruptors can have health benefits, and the rodent effects don't occur in humans.

Of course, no amount of exculpatory data will be enough to convince the true believers, and that's fine, as long as they are not in positions of authority.


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