September 5, 2008
NIH Podcast Episode #0066
Balintfy: Welcome to the 66th episode of NIH Research Radio with news about the ongoing medical research at the National Institutes of Health--the nation's medical research agency. I'm your host Joe Balintfy. Coming up in this episode, how a foster care program reduces delinquency and improves school work for girls; and an in-depth interview with two experts on bisphenol A (BIS-fen-nall). But first a report that 4th- and 8th-graders' math and reading scores are rising, but so are teen births. That's next on NIH Research Radio.
(BREAK FOR PUBLIC SERVICE ANNOUNCEMENT)
4th and 8th Graders' Math and Reading Scores Rising, but so are Teen Births
Balintfy: A recent federal report shows both good news and bad news about America’s youth. Wally Akinso brings us the story:
Akinso: The nation's fourth and eighth graders scored higher in reading and mathematics than they did during their last national assessment.
Alexander: This year, the things that are getting better included, first of all, reading and math scores for children in this country in the 4th grade and again in the 8th grade.
Akinso: Dr. Duane Alexander is the Director of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
Alexander: This is particularly exciting finding because it suggest that we are effectively translating some of our research findings and how better to teach reading and math skills to children into practice in the schools.
Akinso: Not all of the findings were positive. This year's federal report also saw an increase in teenage births. The birth rate among adolescent girls ages 15 to 17 increased, from 21 live births for every 1,000 girls in 2005, to 22 per 1,000 in 2006.
Dr. Alexander explains some of the risks and possible complications associated with teenage births.
Alexander: Teens having babies disadvantage both themselves and their infant. They're more likely to drop out of high school and never complete it, have difficulty getting jobs in the future, and live a life in poverty. And their children are less likely to do well. Their kids are more likely to be born prematurely and have these things that are associated with that.
Akinso: Dr. Alexander says another trend shown on the report was an increase in low birthweight infants.
Alexander: That's gone up again this year from 8.2 percent of all births to 8.3 percent. We don't know quite why this is happening.Akinso: Although not all the reasons for the increase are known, Dr. Alexander says infertility therapies, delayed childbearing and an increase in multiple births may be contributing factors. The report was compiled by the Federal Interagency Forum on Child and Family Statistics. For more information, visit www.childstats.gov. This is Wally Akinso at the National Institutes of Health Bethesda, Maryland.
Foster Care Program Reduces Delinquency and Improves School Work for Girls
Balintfy: In this next report, Wally Akinso explains how a study shows the importance of foster care programs for juvenile delinquent girls.
Akinso: Parental abuse during childhood increases the risk of involvement with the juvenile justice system, according to a study funded by the National Institute on Drug Abuse.
Compton: This study is a long term follow up of girls who are treated in juvenile justice.
Akinso: Dr. Wilson Compton is the Director of the Division of Epidemiology, Services and Prevention Research at NIDA.
Compton: It's comparing a therapeutic foster care to the standard group home approach for treating these juvenile delinquent girls.
Akinso: The study of the Multidimensional Treatment Foster Care intervention for delinquent teenage girls with histories of maltreatment, showed that girls enrolled in the foster care were more likely to be engaged with school work, and as a result, less likely to spend time in locked settings such as jail, compared with girls placed in standard group care. Dr. Compton highlights the findings.
Compton: We've known for several years that therapeutic foster care can be a very useful treatment approach for juvenile delinquent boys. And based on the results of this study we can be quite optimistic about its use for juvenile delinquent girls as well. They previously had reported the one year findings. But what's very exciting is that when you follow up these girls, two years after they were initially found in juvenile courts, that their outcomes continue to improve. So they're even better at two years. And the differences between the standard group home treatment and the therapeutic foster care are even greater at two years than they were in one year.
Akinso: In addition, the biological families of the Multidimensional Treatment Foster Care girls participated in family therapy where they received information on parenting skills that they participated during home visits with their daughters. Dr. Compton says that improving the outcomes for adolescents in this demographic, is a necessary goal.
Compton: We're always looking for ways to improve the outcomes of these very high risk adolescents. So this is a market improvement in our ability to take care of delinquent girls. We've had a fair amount of success in improving the outcomes of delinquent boys and this adds to the information regarding the other gender.
Akinso: Dr. Compton says that the only limitation he sees is that the study was relatively small; he would like to have a large replicated study. This is Wally Akinso at the National Institutes of Health Bethesda, Maryland.Balintfy: Coming up: what you need to know about bisphenol A and the latest report on its safety.
(BREAK FOR PUBLIC SERVICE ANNOUNCEMENT)
Bisphernol A Interview
Balintfy: Bisphenol A or BPA, is a chemical used in many polycarbonate plastics and epoxy resins. According to a final report released September 3rd by the National Toxicology Program or NTP, current human exposure to BPA is of “some concern” for effects on development of the prostate gland and brain, and for behavioral effects in fetuses, infants and children.
For more on this important topic, we turn to two experts from the National Institute of Environmental Health Sciences: Dr. John Bucher (BU-ker), Associate Director of the NTP, and Dr. Michael Shelby, Director of the Center for the Evaluation of Risks to Human Reproduction, or CERHR (SEAR), also from the NTP.
Thank you both for being here. First, Dr. Shelby can you explain what exactly is BPA and how are people exposed to it?
Dr. Shelby: Bisphenol A is a chemical that's used to produce polycarbonate plastics and epoxy resins. Polycarbonate plastic is used to make water bottles as well as baby bottles; and epoxy resin is used to line food cans - metal food cans. After producing this polycarbonate plastic and the epoxy resin there's some residual bisphenol A remaining in the product. And this bisphenol A, the individual molecules, can leech out of the plastic or the epoxy resin into food or drink that is contained within these bottles or cans. In addition, we believe that as the plastic or epoxy resin decomposes, that additional bisphenol A becomes available to leech out into food and drink.
Balintfy: Dr. Shelby could you please explain why the NTP decided to review bisphenol A research?
Dr. Shelby: There were four factors that led us to undertake this evaluation. First, bisphenol A is a high production volume chemical. Second, the vast majority of people in the United States are exposed to bisphenol A. Third, there is a large scientific literature reporting studies on the developmental and reproductive toxicity of bisphenol A. And fourth, there's a high level of public concern about potential public health effects of bisphenol A.
Balintfy: Now, Dr. Bucher in some cases the NTP report concluded there is "some concern" about bisphenol A exposure. What does "some concern" mean?
Dr. Bucher: Well the evidence that we evaluated during the CERHR review for reproductive and developmental effects of bisphenol A is comprised of a large number of studies in animals, as well as a very, very small number of studies actually looking at the effects of bisphenol A in humans. The studies in humans are really inadequate to reach any kind of a conclusion, but the studies in animals have shown a variety of effects at very, very low levels. Where when bisphenol A is given to pregnant animals, the offspring of these animals have shown some effects on development and behavioral effects; and although these are not completely understood with regard to how these effects might translate into human, actual human effects and human risks, the fact that we're seeing these at levels of bisphenol A exposures that are not particularly far different from those that are experienced by humans, would indicate to us that these effects can not be completely dismissed at this point. So "some concern" is actually in the middle part of a 5-level concern scale that we have that ranges from "negligible concern" to "serious concern" and it reflects the fact that the scientists that have looked at this information recognize that there is something really going on here, but it's not exactly clear.
Dr. Shelby: Our evaluation of bisphenol A is the most difficult and challenging evaluation that we have ever conducted.
Balintfy: And Dr. Shelby, why would you say that?
Dr. Shelby: There is a vast amount of literature that we took under consideration. The expert panel report cited over 500 references. But I think the main problem that we encountered, the problem that kept repeating itself, was having a body of information, of literature on a specific topic, that was in disagreement, that reported conflicting results, that conducted experiments using protocols that prevented us from making valid comparisons of results from one experiment to another.
Balintfy: Dr. Shelby, what exactly was it that allowed you to reach some conclusions concerning the specific exposures to infants and children?
Dr. Shelby: Ultimately it was a few areas where there was some consistency among the effects reported and the exposure levels at which those effects were observed. We felt that the literature available to us justified the conclusions that we reached; and the reasons for that are spelled out in the brief on bisphenol A.
Balintfy: So, Dr. Bucher, are some people more likely than others to have effects from bisphenol A?
Dr. Bucher: Well, bisphenol A is metabolized by enzyme systems that change in their activity as humans age and as animals age, so we found that the ability of the body to metabolize and eliminate bisphenol A is much greater in adults than it is in infants and children, so this is one of the reasons that we've expressed some concern over exposures to infants and children, primarily, and negligible concern for reproductive and developmental effects with exposures to adults.
Balintfy: Dr. Bucher, could you recap the overall conclusions that are in the final report on bisphenol A?
Dr. Bucher: The key conclusions of the report included expression of “some concern” over the potential for developmental toxicicty for fetuses, infants, and children. And this was based primarily on evidence from animal studies that would suggest that there might be effects on the development of the prostate gland, and the brain, and also for the potential for behavioral effects in developing organisms. There was also a lower level of concern, minimal concern, expressed over potential for changes in the development of the mammary gland and also for the age at which females attain puberty. There was also a level of minimal concern expressed for workers exposed in occupational settings. But with the exception of that, exposures to adults were considered to be not particularly risky for exposures to BPA.
Balintfy: Dr. Bucher this is a very long and detailed report, could you please tell us what is the take home message for people who want to know about the report on bisphenol A?
Dr. Bucher: Well, you're absolutely right - it is a long and detailed report and the reason it's long and detailed is that there are so many levels of uncertainty in the information that's been developed on BPA with regards to its risks for human reproduction and development. The fact that there are so many levels of uncertainty make it very difficult for us to make any kind of overall recommendations as to how exactly the U.S. public should view bisphenol A right at this point, but it clearly has also identified a number of research areas that we think need to be followed up on in great detail to give us a better handle and reduce some of these uncertainties and allow a clearer picture of exactly what we should be doing as a society with regards to exposures to BPA.
Balintfy: Dr. Bucher and Dr. Shelby, thank you very much. Also thanks to the NIEHS communications team for their production assistance. For more information about BPA, the National Toxicology Program and its report, start your search at www.niehs.nih.gov.
Balintfy: That's it for this episode of NIH Research Radio. Please join us again on Friday, September 19th when our next edition will be available for download. I'm your host, Joe Balintfy. Thanks for listening.
NIH Research Radio is a presentation of the NIH Radio News Service, part of the News Media Branch, Office of Communications and Public Liaison in the Office of the Director at the National Institutes of Health in Bethesda, Maryland, an agency of the US Department of Health and Human Services.