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spaceWindham GC, Pinney SM, Sjodin A, Lum R, Jones RS, Needham LL, Biro FM, Hiatt RA and Kushi LH. (2010) Body burdens of brominated flame retardants and other persistent organo- halogenated compounds and their descriptors in US girls. Environ. Res 2010

Article summary

Background: During the last few decades, concern has grown about the possible health effects of environmental contaminants that may act like, or interfere with, hormones in the body. Hormones control many bodily functions, including the reproductive system, and growth and development in children. Some of the chemicals of original concern were banned in many Western countries (such as the pesticide, DDT, and the PCBs), but they stay in the environment and the food chain for many years. More recently, chemicals used as flame retardants (the PBDEs) have been found to be increasing in the environment and in humans, but little data has been available on children. Exposure to these persistent chemicals in children is thought to be through the diet (including breast feeding), as well as in dust for PBDEs. The goal of this paper was to report measures of PBDEs (polybrominated diphenyl ethers), PCBs (polychlorinated biphenyls), and certain chlorinated pesticides, such as DDT, and its by-product, DDE, in children, and to describe how they vary by factors such as race, geographic location, parents’ education, age  and breast-feeding.

Study Design: To study possible reasons for a trend towards earlier puberty in girls and a link of early puberty to higher breast cancer risk, a national study (called the Breast Cancer and the Environment Research Centers, or BCERC) is being conducted, sponsored by the National Institutes of Health. The Centers include studies of animals, as well as humans, in which 6-8 year old girls are being followed annually to assess growth and pubertal development.  The study protocol includes physical exams, interviews with parents, and collection of urine and blood samples.  One of the many factors of interest is exposure to chemicals. Nearly 600 blood samples from the California and Ohio sites were analyzed for 35 types (called congeners) of PCBs, 11 PBDE congeners, and 9 pesticides at the Centers for Disease Control and Prevention.  We looked at which chemicals were most frequently detected by the laboratory, the range and average of their levels, and how they compare across sub-groups and to another national sample.

Results:

  1. PBDEs: Seven congeners were found in greater than 60% of girls, with BDE-47 having the highest concentration (median 42.2, range 4.9-855 ng/g lipid). Girls in California had higher average levels of these than girls in Ohio, even accounting for the other factors. Furthermore, Blacks had higher average PBDE levels than Whites, and Hispanics had intermediate values. Levels also tended to be lower among more obese girls, but did not vary much by the other factors.
  2. PCBs: Ten PCBs were detected in more than 60% of girls, with five found in nearly all girls.  In contrast to PBDEs, the PCBs detected most often showed lower average levels among Black and Hispanic than among White girls.  Levels of the PCBs were also consistently lower among girls who were more obese, not breastfed, whose mothers were younger, or whose caregivers (usually parents) were less educated. Girls in California had higher levels than those in Ohio for most PCBs, but the opposite for two PCB congeners (CB-99 and -118).
  3. Chlorinated Pesticides: Three pesticides were detected in more than 60% of the girls, with DDE found in nearly all and at far higher levels than the other two pesticides (t-nonachlor and hexachlorobenzene).  The same patterns with the other factors and PCB levels were generally found for these pesticides.
  4. Compared to the National Health and Nutrition Examination Survey (NHANES), the average levels of PBDEs in our study were higher, while levels of PCBs and pesticides were similar. This may in part be due to our study looking at more recent years and younger children than NHANES (12-19 yrs in 2003-2004), because young kids may be more likely exposed to dust, and thus PBDEs, from certain play behaviors.

Conclusions: Several of these persistent chemicals that may act like hormones were detected in nearly all of these young girls. The laboratory methods used have become quite sensitive, so low levels can be detected. Levels varied by geographic location and other factors that may reflect exposure pathways. This is the first study to examine individual PBDE levels in elementary school-aged children in the U.S., reporting higher average values than earlier studies. The higher PBDE levels in California than in Ohio suggest greater exposure, as the difference was not explained by other factors examined. A recent study of dust samples taken from homes in California and Massachusetts found PBDE levels were 3-9 times higher in CA. Unlike other states, California has a history of more stringent regulations regarding flammability of upholstered furniture that can only be met by the addition of flame retardants, such as PBDEs. Some PCBs and pesticides also tended to be higher in California than Ohio girls, although generally lower than 10-20 years ago. Pesticide exposure patterns differ in countries outside the U.S. A larger influx of immigrants (e.g. the parents) to CA from countries in Latin America and Southeast Asia, where some of these persistent pesticides are still used, may partly explain higher levels in their offspring, from transfer during pregnancy or breast-feeding. However, we did not measure levels in mothers. Breast-feeding is still recommended because of the many other benefits to babies. In future analyses, we will examine the relationship of chemical levels to growth and obesity in more detail, as well as to age at puberty.

Article citation:
Body Burdens of Brominated Flame Retardants and Other Persistent Organohalogenated Compounds and their Descriptors in U.S. Girls.
Gayle C. Windham, Susan M. Pinney, Andreas Sjodin, Raymond Lum, Richard S. Jones, Larry L. Needham, Frank M. Biro, Robert A. Hiatt, Lawrence H. Kushi.
CA Department of Public Health, Richmond, CA; University of Cincinnati College of Medicine, Cincinnati, OH; Centers for Disease Control and Prevention, Atlanta, GA; Impact Assessment Inc., San Diego, CA, USA; University of California San Francisco, CA;  Kaiser Permanente Northern California, Oakland, CA.
Environmental Research online Feb 2, 2010

Address correspondence to Dr. Gayle Windham, CA Dept of Public Health, DEODC, 850 Marina Bay Pkwy, Bldg P, Richmond, CA 94804. Phone: 510-620-3638, e-mail: gayle.windham@cdph.ca.gov

Link to article: doi:10.1016/j.envres.2010.01.004

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