A study by doctors at German and Swiss hospitals suggests that use of intravenous feeding systems containing a well-known phthalate can increase the risk of liver problems in babies.
But the chemical industry said that the study did not consider all potential factors and dismissed some that could have contributed to differing results between the test groups.
You have to challenge the conclusions, based on the data that was presented, said Steve Risotto, senior director of the phthalates ester panel of the American Chemistry Council, in a July 29 phone interview.
The data is not highly reliable, [researchers] didn't look at all the factors, and they didn't make a cogent argument as to the cause and effect, he said.
The study, published July 27 in the medical journal Pediatrics, found that 15 of 30 premature and newborn infants who received intravenous nutrition through IV tubes containing di(2-ethylhexyl)phthalate [DEHP] developed signs of cholestatic jaundice [resulting from abnormal bile flow in the liver].
The study said that only six of 46 infants who were fed through DEHP-free tubing got jaundice.
Arlington, Va.-based ACC pointed to differences in treatment that it said were not taken into account in the study's conclusions.
For example, the infants in the phthalate group received treatments that lasted longer 26.2 days compared to 22.2 days for the non-phthalate group.
In addition, the phthalate group received an average of 16.6 treatments, or nearly five times as many as the non-phthalate group, which received an average of only 5.6 treatments.
There is a higher incidence [of jaundice], but the study didn't take into account other factors that could have contributed to that, Risotto said.
He said the study also dismissed in non-defensible ways two other factors surgical interventions and systemic infections that researchers said increased the risk of patients contracting cholestatic jaundice.
The study calculated that systemic infections could cause a fivefold increase in the risk of developing cholestasis [blockage of bile flow] and that conditions requiring surgical interventions could increase that risk nearly 34 times.
According to ACC, the study dismissed the potential for increased risk from systemic infections as statistically not significant, and ignored the risk factor from surgical interventions.
The study also claimed that a 5.6 times increase in risk for hepatobiliary [liver and gallbladder] dysfunction from the use of IVs with DEHP was statistically significant without giving supporting data, the council said.
It took a great leap of faith on [the researchers'] part to say DEHP is the cause, Risotto said.
He said that the study did not measure DEHP exposure and also did not address what types of drugs were administrated to the premature babies a significant omission, because penicillin-derived drugs, in particular, can increase the risk of contracting cholestasis.
Phthalates are used to soften chemicals and are found in bath toys, teethers and bibs.
The U.S. Consumer Product Safety Improvement Act, which went into effect Feb. 10, bans the sale of toys for children 12 or younger or child-care articles for children 3 and under when those items contain more than 0.1 percent of any of three phthalate types: DEHP, dibutyl phthalate and butyl benzyl phthalate.
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