Critiques of the Children’s Amalgam Trials
In 2006, the Journal of the American Medical Association published two articles that have been widely regarded as proving that amalgam dental fillings are safe for children:
Timothy A. Rouen, et. Al., Neurobehavioral effects of dental amalgam in children, JAMA 295(15): 1784-92. 2006.
David C. Bellinger, et. al., Neuropsychological and renal effects of dental amalgam in children, JAMA 295(15): 1775-83. 2006
IAOMT members realized immediately that, once again, the fix was in. These studies were flawed in a myriad of ways, both scientifically and ethically. In the attached articles, Sandy Duffy, JD, finds that the process of informed consent in both studies fell far below recognized ethical standards. Boyd Haley, PhD, finds major scientific flaws in the study designs and conclusions. An editorial by Herbert Needleman, MD, cautioning readers not to draw “unwarranted conclusions from these limited studies,” was published in the JAMA along with the two articles.
These studies were designed to prove that amalgams are safe. In other words, they were designed to fail.
According to Dr. Haley’s critique, the major scientific problems with the studies are that they:
- Ignored measuring the amount of mercury exposure to children by first determining the amount of mercury emitted from an average sized amalgam outside of the mouth. No in vitro data is given to establish a possible dose.
- Used urine and blood mercury levels, when 90% -plus of mercury is excreted in the feces. This obviates any conclusions they make, as urine mercury levels are unreliable with regards to exposure, which is exactly what their own data shows.
- Did not select the most sensitive clinical testing parameters for detecting mercury toxicity but instead used testing parameters that are known to fluctuate without known cause, or parameters that require much longer-term low level exposure to show an affect.
- Did not state that their conclusions of amalgam safety should not include children with any prior neurodevelopmental or systemic illness, because that sensitive sub-population was excluded from the trials..
- Ignored the drop in mercury excretion in the urine after year 2 even though the mercury exposure from amalgams remained the same or increased. This is a sure sign of the subjects losing their ability to excrete mercury with continued exposure to this toxic metal.
- Suppressed their porphyrin profile data, which was collected but not published, and dismissed with an offhand comment.
These studies were poorly designed and tell us one thing of good value – that children with amalgams most likely slowly lose their ability to excrete mercury after about two years of amalgam exposure. This experiment should have been done on primates, not humans and present a serious question of ethics in medicine.
In fact, one of the study authors, James Woods, and others, published an analysis of the data in 2007, that showed evidence of renal damage and differences between boys and girls in the abiity to excrete mercury in the urine. (Woods JS, Martin MD, Leroux BG, DeRouen TA, Leitao JG, Bernardo MF, et al. 2007. The contribution of dental amalgam to urinary mercury excretion in children Environ Health Perspect 115:1527Ð1531). The study data demonstrate a declining ability for the male children’s kidneys to excrete mercury via the urine after the 2nd year of continued mercury exposure from their amalgam fillings.
Barregard (Barregard L, Trachtenberg F, McKinlay S.0, Renal effects of dental amalgam in children: the New England children’s amalgam trial. Environ Health Perspect. 2008 Mar;116(3):394-9) showed a “significantly increased prevalence of microalbuminuria in the children in the amalgam group (CAT study) in the years 3-5.” This is consistent with increased kidney damage and not consistent with a conclusion of safety for dental amalgams as previously stated by the authors of the CAT studies.
More recently, Gianpaolo Guzzi and Paolo Pigatto, leading metal toxicology researchers in Italy, critiqued and amplified the Woods article in a letter, attached below.
- CAT Duffy Legal Critique
- CAT Haley Scientific Critique
- Consumers for Dental Choice Brief
- Guzzi Letter
- Needleman Editorial