Children's Health in the News
2011
Last updated 12/05/2011
CONCLUSIONS: Exposure to some phthalates in utero may decrease child mental and motor development and increase internalizing behaviors (emotionally reactive, anxious/depressed, somatic complaints, withdrawn).
METHOD:Over the study period, 2003–2004, 763 cases – children diagnosed with one of the cancers observed in this study -- and 1,681 controls – children free of cancer -- less than 15 years old were included. Age and sex distribution of the controls were the same as the cases. The ESCALE data were collected by a standardized telephone interview of the mothers of qualified participants for this study. Various indicators of exposure to traffic and pollution were determined using the geocoded addresses at the time of diagnosis for the cases and of interview for the controls. Indicators of the distance from, and density of, main roads and traffic nitrogen dioxide (NO2) concentrations derived from traffic emission data were used.
December 2011
Title
Prenatal Concentrations of PCBs, DDE, DDT and Overweight in Children: A Prospective Birth Cohort Study
Author(s)
Damaskini Valvi, Michelle A. Mendez, David Martinez, Joan O. Grimalt, Maties Torrent, Jordi Sunyer, Martine Vrijheid
Citation
Environmental Health Perspectives (2011), http://dx.doi.org/10.1289/ehp.1103862
Abstract
BACKGROUND: Recent experimental evidence suggests that prenatal exposure to endocrine-disrupting chemicals may increase postnatal obesity risk, and that these effects may be sex- or diet-dependent.
GOAL: This study explored whether prenatal organochlorine compound (OC) concentrations (polychlorinated biphenyls (PCBs), dichlorodiphenyl-dichloroethylene (DDE) and dichlorodiphenyl-trichloroethane (DDT)) were associated with overweight at age 6.5 years and whether child sex or fat intakes modified these associations.
METHOD: 344 children were observed from a Spanish birth cohort established in 1997/98. Overweight at 6.5 years was defined as a body mass index (BMI) greater than 18.2 kg/m2 of the World Health Organization (WHO) reference. Cord blood OC concentrations were measured. Children’s diet was assessed by food frequency questionnaire.
RESULTS: Results showed an association between increased risk of overweight and exposure to PCB and DDE. No association with DDT exposure in the population overall was observed although DDT was associated with overweight in boys. Associations between overweight and PCB and DDE concentrations were strongest in girls.
CONCLUSIONS: This study suggests that prenatal OC exposures may be associated with overweight in children and that sex may influence susceptibility.
Policy Implications
The production and use of PCB, DDT, and DDE (a metabolite of DDT), have been banned or restricted by the Stockholm Agreement, along with several other persistent organic pollutants (POPs) considered to be the most hazardous to human health and the environment. However, these chemicals persist for many years in the environment, accumulating as they progress up through the food chain. Thus, most of current human exposure is through food.
In addition to the Stockholm Agreement, the U.S. has played a leading role in the reduction and elimination of POPs at a global level. Efforts include the active support of the Convention on Long-Range Transboundary Air Pollution and the Basel Convention, as well as the establishment of the Commission for Environmental Cooperation and the Chemicals Information Exchange and Networking Project.
While the Basel Convention addresses the protocol surrounding POPs waste, the signed Parties to the Stockholm Convention are not required to remediate sites contaminated with POPs. This puts populations residing in or near these areas at disproportionately greater risk for exposure and associated adverse health effects.
To better protect human health, and especially that of children, the U.S. needs to adopt a more proactive and preventive approach to chemical policy that includes adequate testing of chemicals using exposure models based on the most vulnerable subsets of the population.
Web link
Full article courtesy of Environmental Health Perspectives here .
Keyword(s)
body mass index, dichlorodiphenyl-dichloroethylene (DDE), dichlorodiphenyltrichloroethane (DDT), environmental obesogens, high-fat intakes, obesity, persistent organic pollutants, polychlorinated biphenyls (PCBs)
November 2011
Title
Climate Extremes and the Length of Gestation
Author(s)
Payam Dadvand, Xavier Basagaña, Claudio Sartini, Francesc Figueras, Martine Vrijheid, Audrey de Nazelle, Jordi Sunyer, and Mark J. Nieuwenhuijsen
Citation
Environmental Health Perspectives 119:1449–1453 (2011). http://dx.doi.org/10.1289/ehp.1003241
Abstract
BACKGROUND: Although future climate is predicted to have more extreme heat conditions, the available evidence on the impact of these conditions on pregnancy length is very scarce and inconclusive.
GOAL: To investigate the impact of maternal short-term exposure to extreme ambient heat on the length of pregnancy.
METHOD: This study was based on a cohort of births that occurred in a major university hospital in Barcelona during 2001–2005. Three indicators of extreme heat conditions based on 1-day exposure to an unusually high heat–humidity index were applied. Each mother was assigned the measures made by the meteorological station closest to maternal residential zipcodes. A two-stage analysis was developed to quantify the change in pregnancy length after maternal exposure to extreme heat conditions adjusted for a range of factors. The second step was repeated for lags 0 (delivery date) to 6 days.
RESULTS: This study included data from 7,585 pregnant women. A 5-day reduction in average gestational age at delivery after an unusually high heat–humidity index on the day before delivery was estimated.
CONCLUSIONS: Extreme heat was associated with a reduction in the average gestational age of children delivered the next day, suggesting an immediate effect of this exposure on pregnant women.
Implications
Reduced gestational age at delivery is a leading cause of infant mortality in the U.S. Those pre-term babies who survive are at higher risk for adverse health and developmental outcomes, some of which have been found to be associated with as little as a one week reduction in gestational age.
The findings from this study indicate a negative association between maternal exposure to extreme heat and gestational age at delivery in humans, supporting similar existing research on animals, as well as a study of pre-term labor rates in relation to heat-humidity indices.
Increased frequency, intensity and severity of extreme heat episodes are expected with climate change, and thus, this study’s findings contribute to the mounting evidence that global climate change represents a serious human health hazard, especially to already vulnerable populations.
Policy Implications
Individual, state- and regional-level actions and policies adopted to address climate change are insufficient without a larger, comprehensive framework. Strong federal and international systematic efforts are necessary to effectively reduce heat-trapping gasses. The U.S. Environmental Protection Agency’s (EPA’s) current approaches to greenhouse gas reduction initiatives involve primarily voluntary partnerships with industry through programs such as Climate Leaders and Energy Star. EPA is also in the process of developing and issuing emissions standards for both mobile (vehicular) and stationary (industry) sources under the existing Clean Air Act. A 2009 bill passed by the House that would have set the first-ever emissions limits on these polluting gasses did not pass the Senate. Federal legislation effectively addressing global climate change must be enacted. It is also essential for the U.S. to fully participate in international climate negotiations to develop and honor a new global treaty of greenhouse gas reductions to better protect the health of future generations worldwide.
Web link
Full article courtesy of Environmental Health Perspectives here.
Keyword(s)
climate, climate change, gestational age, global warming, hot temperature, perinatal mortality, pregnancy outcome, preterm birth
October 2011
Title
Maternal Prenatal Urinary Phthalate Metabolite Concentrations and Child Mental, Psychomotor and Behavioral Development at Age Three Years
Author(s)
Robin M. Whyatt, Xinhua Liu, Virginia A. Rauh, Antonia M. Calafat, Allan C. Just, Lori Hoepner, Diurka Diaz, James Quinn, Jennifer Adibi, Frederica P. Perera, Pam Factor-Litvak
Citation
Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.1103705
Abstract
BACKGROUND: Phthalates are a class of more than 50 high production volume chemicals added to a wide variety of consumer products including plastics, solvents, vinyl flooring, adhesives, and personal care products. Biomonitoring studies indicate that phthalate exposure is widespread in the U.S. population, and phthalates have also been shown to cross the placenta, thereby exposing unborn children.
Research suggests prenatal phthalate exposures affect child executive function and behavior.
GOAL: To evaluate associations between phthalate metabolite concentrations in maternal prenatal urine and mental, motor and behavioral development in children at age 3 years.
METHOD: Four phthalate metabolites (mono-2-ethylhexyl phthalate, MiBP - mono-isobutyl phthalate, MnBP - mono-n-butyl phthalate, mono-benzyl phthalate) were measured in a spot urine sample collected from 319 women during the 3rd trimester of pregnancy. The children of these pregnancies were assessed at 3 years of age. The Mental Development Index (MDI) and Psychomotor Development Index (PDI) were measured using the Bayley Scales of Infant Development II, and behavior problems were assessed by maternal report on the Child Behavior Checklist.
RESULTS: MnBP and MiBP metabolite concentrations during pregnancy were significantly associated with decreases in psychomotor development and with increased odds of psychomotor delay. In girls, but not boys, maternal prenatal MnBP was also associated with a significant decrease in mental development at 3 years of age. Boys had significantly higher scores than girls on attention problems. Further, MnBP, MiBP, and MBzP were significantly associated with increases in a number of behavioral problems in the internalizing domains which include symptoms of withdrawal, anxiety and depression. Significant sex differences were seen in these associations, particularly with MnBP and MBzP.
CONCLUSIONS: Exposure to some phthalates in utero may decrease child mental and motor development and increase internalizing behaviors (emotionally reactive, anxious/depressed, somatic complaints, withdrawn).
Policy Implications
This study by Whyatt et al. is consistent with existing literature that shows an association between prenatal exposure to phthalates and postnatal cognitive and behavioral deficits.
Regulation of phthalates in the United States (US) has been developed largely in response to the compelling findings of adverse effects on the development of the reproductive system in males prenatally exposed to phthalates.
In 2008 the Consumer Product Safety Improvement Act was enacted into law. Under this law the concentrations of 3 specified phthalates in children’s toys and other child care related articles manufactured, imported, distributed or sold in the US are limited to no more than 0.1 percent of the total mass of the entire product. An additional 3 phthalates are similarly limited in child care articles and in toys, but only in those toys that can be placed in or brought to a child’s mouth for sucking or chewing.
In 2010 the US Environmental Protection Agency (EPA) initiated rulemaking to add 8 phthalates to the Concern List under the Toxic Substances Control Act (TSCA) and to add 6 phthalates not already on the Toxics Release Inventory (TRI) as part of its overall phthalate action plan. The plan also includes initiating rulemaking in 2012 under TSCA section 6(a) to regulate the 8 phthalates of concern. The proposed regulation will be informed by assessments conducted by the US Food and Drug Administration, the Consumer Product Safety Commission’s Chronic Hazard Advisory Panel, and EPA’s Integrated Risk Information System.
EPA will evaluate the potential for disproportionate impact on children as part of the rulemaking. Meanwhile, more research is needed, particularly concerning multiple exposures, such as multiple phthalates exposures, and research on the approximately 42 phthalates that will remain unregulated.
Slow action at the national level has led numerous state legislators to introduce legislation to limit children’s exposure to phthalates.
A more proactive approach toward toxicity testing and regulation of all chemicals prior to manufacture and use in the US would better protect children’s health.
Web link
Full article courtesy of Environmental Health Perspectives here.
September 2011
Title
Formaldehyde Exposure and Lower Respiratory Infections in Infants: Findings from the PARIS Cohort Study
Author(s)
Célina Roda, Isabelle Kousignian, Chantal Guihenneuc-Jouyaux, Claire Dassonville, Ioannis Nicolis, Jocelyne Just, Isabelle Momas
Citation
Environmental Health Perspectives doi:10.1289/ehp.1003222
Abstract
BACKGROUND:Certain chemical pollutants can exacerbate lower respiratory tract infections (LRI), a common childhood ailment. Although formaldehyde is one of the most common air pollutants found in indoor environments, its impact on infant health is uncertain.
GOAL: To determine the impact of formaldehyde exposure on the LRI incidence during the first year of life of infants from the PARIS birth cohort. (The PARIS cohort consists of 3,840 healthy newborns recruited in five Paris maternity hospitals from 2003 to 2006.)
METHOD: Formaldehyde was measured in a random sample of 196 infants’ dwellings, and exposure to this pollutant was estimated for 2,940 infants. Health data were collected from parents by regular self-administered questionnaires. Associations between formaldehyde exposure and the occurrence of (wheezy) LRI were also estimated.
RESULTS: During the first year of life, 45.8% of infants had at least one LRI, and LRI occurred simultaneously with wheezing in 48.7% of cases. Calculations for prediction correctly classified 70% of dwellings as having high or low exposure, and it was estimated that 43.3% of infants were exposed throughout the first year to levels of formaldehyde above 19.5 Kg/m3. Formaldehyde exposure was significantly associated with (wheezy) LRI.
CONCLUSIONS: The findings of this study suggest that infants exposed to formaldehyde at an early age have an increased incidence of LRI.
Policy Implications
It is well-established that formaldehyde is an irritant to upper and lower respiratory airways, in non-occupational (e.g., domestic) as well as occupational settings. This chemical is ubiquitous in indoor environments, which is where infants spend the majority of their time. This study found an association between chronic exposure to formaldehyde and the occurrence of lower respiratory infection during the first year of life in a large birth cohort. Previous studies suggest that infections during infancy, an important period of lung growth, may have deleterious effects on later respiratory function, such as the development of asthma.
Much of the general population’s exposure to formaldehyde is through pressed-wood products. The promulgation of strict emissions standards for these products and the materials used in their construction are needed to protect children’s health. In 2010 President Obama signed the Formaldehyde Standards for Composite Wood Products Act into law. This legislation, modeled on standards adopted by the state of California, amends the Toxic Substances Control Act (TSCA) through the addition of Title VI. It mandates regulation of formaldehyde emissions from hardwood plywood, medium-density fiberboard, and particleboard that is sold, supplied, offered for sale, or manufactured in the U.S. It also calls for regulation of the manufacture and sale of finished goods produced from these composite wood products.
How effective this legislation will be at protecting human health remains to be seen. Congress has directed EPA to implement the final regulations by January 1, 2013. EPA has been trying to update its chemical risk assessment for formaldehyde since 1998. Included in this assessment would be research findings sufficient to classify formaldehyde as a human carcinogen, consistent with reports and classifications of both the International Agency for Research on Cancer (IARC) and the Department of Health and Human Services’ National Toxicology Program. Industry continues to delay the release of EPA’s assessment, which could therefore affect the stringency of the 2013 regulations. The health of our population, especially our most vulnerable, is at stake.
Web link
Full article courtesy of Environmental Health Perspectives here.
Keyword(s)
Wheeze, LRI, Formaldehyde
Wheeze, LRI, Formaldehyde
August 2011
Title
A Geospatial Analysis of the Effects of Aviation Gasoline on Childhood Blood Lead Levels
Author(s)
Marie Lynn Miranda, Rebecca Anthopolos, Douglas Hastings
Citation
Environmental Health Perspectives doi:10.1289/ehp.1003231
Abstract
BACKGROUND: Aviation gasoline, commonly referred to as avgas, is a leaded fuel used in small aircraft. Recent concern about the effects of lead emissions from planes has motivated the U.S. Environmental Protection Agency (EPA) to consider regulating leaded avgas.
GOAL: This study investigated the relationship between lead from avgas and blood lead levels in children living in six counties in North Carolina (NC).
METHOD: Geographic Information System (GIS) technology was used to approximate areas surrounding airports in which lead from avgas may be present in elevated concentrations in air and may also be deposited to soil. The relationship between residential proximity to airports and NC blood lead surveillance data in children aged 9 months to 7 years while controlling for factors including age of housing, socioeconomic characteristics, and seasonality was also examined.
RESULTS: The findings suggest that children living within 500 m of an airport at which planes use leaded avgas have higher blood lead levels than other children. This apparent effect of avgas on blood lead levels was evident among children living within 1000 m of airports.
CONCLUSIONS: Significant association between potential exposure to lead emissions from aviation gasoline and blood lead levels in children was observed. While the estimated increase was not especially large, the results of this study are nonetheless directly relevant to the policy debate surrounding the regulation of leaded avgas.
Policy Implications
Significant progress has been made in reducing human exposure to lead in the U.S. with the greatest gains made by banning leaded gasoline and lead-based paint. Efforts to reduce exposure continue, such as recent Federal legislation requiring stricter limits for lead and other hazardous substances in toys and children’s products. However, despite this progress, approximately 270,000 U.S. children aged 1-5 have blood lead levels (BLLs) at or above the CDC’s 10 ug/dL action level. Furthermore, research indicates that children whose BLLs are less than 10 ug/dL suffer considerably greater IQ loss with each additional 1 ug/dL BLL increase compared with children whose BLLs are ≥ 10 ug/dL. In fact the Centers for Disease Control and Prevention states that there is no “safe” blood lead level for children. In 1999-2002, the average BLL for U.S. children aged 1-5 years was 1.9 ug/dL.
Contributing factors to elevated BLLs may include sources of lead exposure that remain unregulated. Emissions from aircraft using unregulated leaded avgas account for approximately 50% of the national inventory of lead emitted to air in the U.S., and represent the single largest source of ambient lead. Prior research indicates that air and soil concentrations of lead are higher in areas that are in close proximity to airports where avgas is used. There are nearly 20,000 airport facilities in the U.S. where leaded avgas is used. Approximately 16 million people live, and 3 million children attend school, within 1000 m of these facilities. This study found that lead from avgas may have a 2.1% - 4.4% impact on the BLLs of children who live near to airports where avgas is used. This may be a relatively small impact; however, adverse cognitive and behavioral effects are linked to even slight increases in BLL.
The Environmental Protection Agency (EPA) strengthened the national ambient air quality standards (NAAQS) for lead in 2008. In 2010 the EPA issued an Advanced Notice for Proposed Rulemaking on leaded aviation fuel, and solicited public comments, but has not established regulatory action. Previous research has established the hazard, and this study contributes to the evidence of exposure. Federal standards to control lead emissions from aircraft that use leaded avgas will be an essential component of regulatory action to protect human health.
Web link
Full article courtesy of Environmental Health Perspectives here.
July 2011
Title
Road Traffic and Childhood Leukemia: The ESCALE Study (SFCE)
Author(s)
Amigou, A., Sermage-Faure, C., Orsi, L., Leverger, G. Baruchel, A., Bertrand, Y., Nelken et al.
Citation
Citation
Environmental Health Perspectives 119:566–572 (2011). doi:10.1289/ehp.1002429
Abstract
BACKGROUND:Traffic is a source of environmental exposures, which may be related to childhood leukemia.
GOALS: A national registry–based case–control study [ESCALE (Study on Environmental and Genetic Risk Factors of Childhood Cancers and Leukemia)] carried out in France was used to assess the effect of exposure to road traffic exhaust fumes on the risk of childhood leukemia.
METHOD:Over the study period, 2003–2004, 763 cases – children diagnosed with one of the cancers observed in this study -- and 1,681 controls – children free of cancer -- less than 15 years old were included. Age and sex distribution of the controls were the same as the cases. The ESCALE data were collected by a standardized telephone interview of the mothers of qualified participants for this study. Various indicators of exposure to traffic and pollution were determined using the geocoded addresses at the time of diagnosis for the cases and of interview for the controls. Indicators of the distance from, and density of, main roads and traffic nitrogen dioxide (NO2) concentrations derived from traffic emission data were used.
RESULTS:Acute leukemia (AL) was significantly associated with estimates of traffic NO2 concentration at the place of residence, and with the presence of a heavy-traffic road within 500 m compared with the absence of a heavy-traffic road in the same area. There was a significant association between AL and a high density of heavy-traffic roads within 500 m compared with the reference category with no heavy-traffic road within 500 m.
CONCLUSION:This study supports the hypothesis that living close to heavy-traffic roads may increase the risk of childhood leukemia.
Policy Implications
Occupational exposure to benzene is an established cause of AL in adults. Also, benzene is known to cross the placenta, and prenatal exposure has been associated with birth defects in other studies. A major source of the general population’s exposure to this aromatic compound is automobile exhaust. The International Agency for Research on Cancer (IARC) classifies
benzene, diesel, and gasoline exhaust fumes as “known”, “probable”, and “possible” human carcinogens, respectively. This study is consistent with several others that found associations between residential proximity to high-density traffic roads, or to high concentrations of NO2 and benzene, and childhood leukemia. Stricter motor vehicle emissions policies and regulations at the federal level are needed to reduce human exposure to these exhaust pollutants. In addition, adoption of innovative regional or local transportation policies, such as investment in sustainable transit programs, the creation of walkable neighborhoods and cities, and integrated bike paths, represent proactive approaches in reducing human exposure to benzene and other hazardous compounds from motor vehicle exhaust.
benzene, diesel, and gasoline exhaust fumes as “known”, “probable”, and “possible” human carcinogens, respectively. This study is consistent with several others that found associations between residential proximity to high-density traffic roads, or to high concentrations of NO2 and benzene, and childhood leukemia. Stricter motor vehicle emissions policies and regulations at the federal level are needed to reduce human exposure to these exhaust pollutants. In addition, adoption of innovative regional or local transportation policies, such as investment in sustainable transit programs, the creation of walkable neighborhoods and cities, and integrated bike paths, represent proactive approaches in reducing human exposure to benzene and other hazardous compounds from motor vehicle exhaust.
Web link
Full article courtesy of Environmental Health Perspectives here.
Keyword(s)
June 2011
Title
7-Year Neurodevelopmental Scores and Prenatal Exposure to Chlorpyrifos, a Common Agricultural Pesticide
Author(s)
Virginia Rauh, Srikesh Arunajadai, Megan Horton, Frederica Perera, Lori Hoepner, Dana B. Barr, Robin Whyatt
Citation
Environmental Health Perspectives doi:10.1289/ehp.1003160
Abstract
BACKGROUND: Researchers of a longitudinal birth cohort study of inner-city mothers and children (Columbia Center for Children’s Environmental Health) have previously reported that prenatal exposure to chlorpyrifos (CPF) was associated with neurodevelopmental problems at child age 3 years.
GOALS: The goal of this study was to estimate the relationship between prenatal CPF exposure and neurodevelopment among cohort children at age 7 years.
METHOD: In a sample of 265 children, participants in a prospective study of air pollution, prenatal CPF exposure using umbilical cord blood plasma (picograms/gram plasma) and 7-year neurodevelopment using the Wechsler Intelligence Scales for Children (WISC-IV) were measured and compared.
RESULTS: On average, for each, Full-Scale IQ declined by 1.4%, and Working Memory declined by 2.8% as CPF exposure increased. Final covariates included maternal educational level, maternal IQ, and quality of the home environment. There were no significant interactions between CPF and any covariates, including the other chemical exposures measured during the prenatal period (environmental tobacco smoke and polycyclic aromatic hydrocarbons).
CONCLUSION: This study reports evidence of deficits in Working Memory Index and Full-Scale IQ as a function of prenatal CPF exposure at 7 years of age. These findings are important in light of continued widespread use of CPF in agricultural settings and possible longer-term educational implications of early cognitive deficits.
Policy Implications
The U.S. Environmental Protection Agency initiated regulatory action to phase out residential use of CPF and other organophosphates (OPs) beginning in 2001. Prior to this, applications of CPF were heavy in urban areas, particularly in residential buildings, and studies found detectable levels in nearly all personal and indoor air samples of pregnant study participants in New York City, as well as in the majority of participants’ cord blood samples taken at delivery.1,2,3 Previous studies have shown that OPs cross the placenta, and this study is consistent with a growing body of evidence that prenatal OP exposure is associated with cognitive and neurobehavioral deficits in young children.4,5,6,7,8
Despite the ban on most residential uses, and despite the fact that OPs are not considered to be persistent organic pollutants, ongoing residential exposure to OPs persists.9 In addition, OPs are still used to control mosquitoes and other insect pests in public spaces, and are commonly sprayed on agricultural crops. Exposure may occur via consumption of conventionally-grown produce10 as well as via inhalation and dermal contact. These results indicate that further restrictions on the use of CPF should be considered.
Web link
Full article courtesy of Environmental Health Perspectives here.
Keyword(s)
pesticides, chlorpyrifos, neurodevelopment
May 2011
Title
A Comparison of PBDE Serum Concentrations in Mexican and Mexican-American Children Living in California
Author(s)
Brenda Eskenazi, Laura Fenster, Rosemary Castorina, Amy R. Marks, Andreas Sjödin, Lisa Goldman Rosas, Nina Holland, Armando Garcia Guerra, Lizbeth Lopez-Carillo, Asa Bradman
Citation
Environ Health Perspect (2011): doi: 10.1289/ehp.1002874
Abstract
BACKGROUND: Polybrominated diphenyl ethers (PBDE), which are used as flame retardants, have been found to be higher in residents of California than of other parts of the U.S.
GOALS: This study investigated the role of immigration to California on PBDE levels in Latino children.
METHOD: The research group compared serum PBDE concentrations in a population of first generation Mexican-American 7-year old children (n=264), who were born and raised in California, with 5-year old Mexican children (n=283), who were raised in the states in Mexico where most mothers, having participated in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, had originated.
RESULTS: On average PBDE serum concentrations in the California Mexican-American children were three times higher than their mothers’ levels during pregnancy and seven times higher than concentrations in the children living in Mexico. The PBDE serum concentrations were higher in the Mexican-American children regardless of length of time their mother had resided in California or the duration of the child’s breastfeeding. These data suggest that PBDE serum concentrations in these children resulted primarily from postnatal exposure.
CONCLUSION: In the first study to assess the relationship between environmental levels of BTEX and NTDs, we found an association between benzene and spina bifida. Our results contribute to the growing body of evidence regarding air pollutant exposure and adverse birth outcomes.
Policy Implications
Two of the three commercially produced preparations of PBDEs have been phased out in the U.S. and Europe since 2004. However, the semi-volatile compounds continue to be released from old furniture, materials and equipment, and are bioaccumulative, persisting in humans and the environment for years. In addition, one preparation, decaBDE, is still used in consumer electronics and wire insulation, among other applications. This study found that the high PBDE body burdens in the 7 year olds in California were primarily due to postnatal exposure sources, including house dust and food. Previous biomonitoring studies indicated that children living in California have some of the highest documented PBDE serum levels worldwide, and exposure studies have revealed higher PBDE levels in house dust collected in California compared with other parts of the U.S. and Canada. These findings may be an unintended consequence of California’s furniture flammability standards, some of which were developed in the 1970’s. The regulations resulted in the addition of millions of pounds of flame retardants to various product materials during manufacturing. Attempts in other regions of the U.S. to meet California’s flammability standards have resulted in the spread of products containing high levels of PBDE throughout the U.S. Some studies indicate that PBDE levels may be higher in lower-income homes due to the presence of poorly manufactured products, aging and deteriorating products, and poorer ventilation.
PBDE crosses the blood-brain barrier and negatively impacts brain development, interferes with thyroid hormone levels, and may cause liver toxicity. Strict regulations of decaPBDEs at the federal and state levels are needed, and local consumer outreach, especially targeted to vulnerable populations, should provide information on potential sources of continuing exposure. Mandatory toxicological testing of other halogenated flame retardants or replacement chemicals should be required of chemical manufacturers prior to commercial use.
Web link
Full article available courtesy of Environmental Health Perspectives here.
Keyword(s)
DDE, DDT, Human Exposure, PBDEs
April 2011
Title
Maternal Exposure to Ambient Levels of Benzene and Neural Tube Defects among Offspring: Texas, 1999–2004
Author(s)
Philip J. Lupo, Elaine Symanski, D. Kim Waller, Wenyaw Chan, Peter H. Langlois, Mark A. Canfield, and Laura E. Mitchel
Citation
2010 Maternal Exposure to Ambient Levels of Benzene and Neural Tube Defects among Offspring: Texas, 1999–2004. Environ Health Perspect 119(3): doi:10.1289/ehp.1002212
Abstract
BACKGROUND: Previous studies have reported positive associations between maternal exposure to air pollutants and several adverse birth outcomes. However, there have been no studies assessing the association between environmental levels of hazardous air pollutants, such as benzene, and neural tube defects (NTDs), a common and serious group of congenital malformations.
GOALS: To conduct a case–control study assessing the association between ambient air levels of benzene, toluene, ethylbenzene, and xylene (BTEX) and the likelihood of NTDs to occur among offspring.
METHOD: The Texas Birth Defects Registry provided data on NTD cases (spina bifida and anencephaly) delivered between 1999 and 2004. The control group was a random sample of unaffected live births, frequency matched to cases on year of birth. Census tract–level estimates of annual BTEX levels were obtained from the U.S. Environmental Protection Agency 1999 Assessment System for Population Exposure Nationwide.
RESULTS: Mothers living in census tracts with the highest benzene levels were more likely to have offspring with spina bifida than were women living in census tracts with the lowest levels. No significant associations were observed between anencephaly and benzene or between any of the NTD phenotypes and toluene, ethylbenzene, or xylene.
CONCLUSION: In the first study to assess the relationship between environmental levels of BTEX and NTDs, we found an association between benzene and spina bifida. Our results contribute to the growing body of evidence regarding air pollutant exposure and adverse birth outcomes.
Policy Implications
Benzene is known to cross the placenta. Previous studies found significant associations between maternal occupational exposure to benzene and other organic solvents and birth defects, including NTDs. This study found an association between prenatal exposure to benzene in ambient air and spina bifida, suggesting that adverse birth outcomes may not be limited to those whose mothers are occupationally exposed. Most of human exposure to benzene, aside from tobacco smoke, is from automobile exhaust and industrial emissions. Stricter industrial and motor vehicle emissions policies and regulations at the federal level are called for to reduce the general population’s exposure to benzene. In addition, adoption of innovative transportation policies, such as investment in sustainable transit programs, the creation of walkable neighborhoods and cities, and integrated bike paths, represent proactive approaches in reducing human exposure to benzene and other hazardous compounds from motor vehicle exhaust.
Web link
Full article available courtesy of Environmental Health Perspectives here.
Keyword(s)
Benzene, toluene, ethylbenzene, xylene
March 2011
Title
Environmental Chemicals in Pregnant Women in the US: NHANES 2003-2004
Author(s)
Tracey J. Woodruff, Ami R. Zota, Jackie M. Schwartz
Citation
Woodruff TJ, Zota AR, Schwartz JM 2011. Environmental Chemicals in Pregnant Women in the US: NHANES 2003-2004. Environ Health Perspect :-. doi:10.1289/ehp.1002727
Abstract
BACKGROUND:
This study reviewed biomonitoring data from the National Health and Nutritional Examination Survey (NHANES) to characterize exposures in U.S. pregnant women to some chemicals linked to human health concerns. NHANES is a nationally representative sample of the U.S. population. Biomonitoring involves analyzing blood, urine and other samples from the survey participants for specific chemicals or their breakdown products. The chemicals analyzed included:
Polybrominated Diphenyl Ethers (PBDEs): a category of flame retardants commonly found in furnishings, computers and electrical appliances. PBDEs can be toxic to the liver, thyroid, and developing nervous system.
Perfluorinated compounds (PFCs): a family of commonly used synthetic compounds with many applications, such as stain repellants. PFCs accumulate in human tissues and emerging evidence suggests reproductive toxicity, neurotoxicity and hepatotoxicity, and some PFCs are considered to be likely human carcinogens. Exposure to PFCs is widespread and some subpopulations, such as living in proximity to fluorochemical manufacturing plants, are highly contaminated. #
Organochlorine pesticides: an older class of pesticides. Many of their uses have been banned due to their environmental persistence and potential adverse effects on wildlife and human health.
Phthalates: a class of chemicals used to soften some plastics, bind fragrances in products, and act as solvents and fixatives. Phthalates have been linked to hormone disruption, developmental and reproductive problems, and other health concerns. Some phthalates have been banned from children’s toys and products.
Polycyclic Aromatic Hydrocarbons (PAHs): a group of over 100 different chemicals that are formed during the incomplete burning of coal, oil and gas, garbage, or other organic substances like tobacco or charbroiled meat. PAHs are usually found as a mixture containing two or more of these compounds, such as soot.
Perchlorate: a naturally occurring and man-made chemical that is used to produce rocket fuel, fireworks, flares and explosives. Perchlorate can also be present in bleach and in some fertilizers. Perchlorate may have adverse health effects because scientific research indicates that this contaminant can disrupt the thyroid’s ability to produce hormones needed for normal growth and development.
Phenols: Phenol is a colorless-to-white solid when pure. Commercial phenol is a liquid that evaporates more slowly than water. Phenol has a distinct odor that is sickeningly sweet and tarry. Phenol is both a manufactured chemical and produced naturally. Phenol is used to make plastics. Phenol is also used as a disinfectant in household cleaning products and in consumer products such as: mouthwashes, gargles, and throat sprays.
METHOD:
Researchers analysed samples from 268 pregnant women from NHANES 2003-2004 . They looked for detectable levels of 163 chemical analytes in 12 chemical classes in the samples from these women. RESULTS: The percent of pregnant women with detectable levels of an individual chemical ranged from 0 to 100 percent. Certain PCBs, organochlorine pesticides, PFCs, phenols, PBDEs, phthalates, polycyclic aromatic hydrocarbons (PAHs) and perchlorate were detected in 99 to 100% of pregnant women. We found, generally, levels in pregnant women were similar or lower than levels in non-pregnant women, adjustment for covariates tended to increase levels in pregnant women compared to non-pregnant women.
CONCLUSION:
Pregnant women in the U.S. are exposed to multiple chemicals. Further efforts are warranted to understand sources of exposure and implications for policy-making.
Policy Implications
Fetal development is a particularly sensitive period of human development, and this analysis confirms the reality of multiple chemical exposures for pregnant women in the U.S. Other studies have shown that many chemicals can cross the placenta. More research on the effects of multiple exposures is necessary. The National Academy of Science recommends that chemical risk assessments, which inform policy, account for the multiple exposures and for exposures that occur during these vulnerable periods of development. This is not currently occurring. Reform of current Federal law that regulates industrial and consumer chemicals is needed to include a more protective approach to human health to better safeguard human health.
Web link
Full article available courtesy of Environmental Health Perspectives here.
Keyword(s)
chemicals, polybrominated diphenyl ethers (PBDEs), perfluorinated compounds (PFCs), organochlorine pesticides, phthalates.
February 2011
Title
Association of secondhand smoke exposure with pediatric invasive bacterial disease and bacterial carriage: a systematic review and meta-analysis.
Author(s)
Lee CC, Middaugh NA Howie SR Ezzati M.
Citation
PLoS medicine. 2010;7(12):e1000374
Abstract
BACKGROUND:
A number of epidemiologic studies have observed an association between secondhand smoke (SHS) exposure and pediatric invasive bacterial disease (IBD) but the evidence has not been systematically reviewed. We carried out a systematic review and meta-analysis of SHS exposure and two outcomes, IBD and pharyngeal carriage of bacteria, for Neisseria meningitidis (N. meningitidis), Haemophilus influenzae type B (Hib), and Streptococcus pneumoniae (S. pneumoniae).
METHOD:
Two independent reviewers searched Medline, EMBASE, and selected other databases, and screened articles for inclusion and exclusion criteria. We identified 30 case-control studies on SHS and IBD, and 12 cross-sectional studies on SHS and bacterial carriage. Weighted summary odd ratios (ORs) were calculated for each outcome and for studies with specific design and quality characteristics.
RESULTS:
Children with SHS exposure were more likely to be found with invasive meningococcal, pneumococcal disease, and Hib disease compared to those unexposed to SHS. The association between SHS exposure and invasive meningococcal and Hib diseases was consistent regardless of outcome definitions, age groups, study designs, and publication year. The effect estimates were larger in studies among children younger than 6 years of age for all three IBDs, and in studies with the more rigorous laboratory-confirmed diagnosis for invasive meningococcal disease.
CONCLUSION:
When considered together with evidence from direct smoking and biological mechanisms, our systematic review and meta-analysis indicates that SHS exposure may be associated with invasive meningococcal disease. The epidemiologic evidence is currently insufficient to show an association between SHS and invasive Hib disease or pneumococcal disease. Because the burden of IBD is highest in developing countries where SHS is increasing, there is a need for high-quality studies to confirm these results, and for interventions to reduce exposure of children to SHS.
Policy Implications
CHILDREN’S EXPOSURE TO SECONDHAND SMOKE SHOULD BE ELIMINATED.
Web link
Full article available courtesy of PLoS Medicine here.
Keyword(s)
tobacco, infection
January 2011
Title
Lead and PCBs as Risk Factors for Attention Deficit/Hyperactivity Disorder
Author(s)
Paul A. Eubig, Andréa Aguiar, Susan L. Schantz
Citation
Environ Health Perspect 118(12): doi:10.1289/ehp.0901852
Abstract
BACKGROUND:
Attention deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder of childhood, with an estimated worldwide prevalence of 5.29% (Polanczyk et al. 2007). ADHD has an onset at early school age and is characterized by impulsive behavior and inattention.
This review highlights the parallels between the performance of ADHD children on tests of working memory, response inhibition, cognitive flexibility, planning, and attention and the performance of children and laboratory animals on similar tasks after developmental exposure to lead or polychlorinated biphenyls (PCBs).
OBJECTIVE:
Although attention deficit/hyperactivity disorder (ADHD) is the most frequently diagnosed neurobehavioral disorder of childhood, yet its causes are not well understood. The researchers present evidence that environmental chemicals, particularly polychlorinated biphenyls (PCBs) and lead, are associated with deficits in many neurobehavioral functions that are also impaired in ADHD.
METHOD:
Human and animal studies of developmental PCB or lead exposures that assessed specific functional domains shown to be impaired in ADHD children were identified via searches of PubMed, an online database of the U.S. National Library of Medicine, using “lead” or “PCB exposure” in combination with key words, including “attention,” “working memory,” “response inhibition,” “executive function,” “cognitive function,” “behavior,” and “ADHD.”
RESULTS:
Children and laboratory animals exposed to lead or PCBs show deficits in many aspects of attention and executive function that have been shown to be impaired in children diagnosed with ADHD, including tests of working memory, response inhibition, vigilance, and alertness. Studies conducted to date suggest that lead may reduce both attention and response inhibition, whereas PCBs may impair response inhibition to a greater degree than attention. Low-level lead exposure has been associated with a clinical diagnosis of ADHD in several recent studies. Similar studies of PCBs have not been conducted.
CONCLUSION:
The researchers speculate that exposures to environmental contaminants, including lead and PCBs, may increase the prevalence of ADHD.
Policy Implications
There is growing evidence that exposures to multiple toxicants, not just lead and PCBs, result in the same, or at least similar, outcomes. Exposure to mercury, alcohol in utero, arsenic, some pesticides, and some endocrine disrupting chemicals have all been associated with attention problems in animals and/or humans. Moreover, metals, inorganic compounds and various organic compounds including solvents, and some pesticides are all known to be neurotoxic, but there is rarely a specific neurotoxic syndrome that is linked to a specific chemical. Therefore, we need to prevent exposures to known toxicants and to identify the neurotoxicity of new compounds before they are brought to market. The current mechanism for regulating potential toxic substances, the Toxic Substances Control Act (TSCA), is totally inadequate for that purpose and is in urgent need of revision.
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Web link
Full article available courtesy of Environmental Health Perspectives here.
Keyword(s)
Lead - cehn.org/ lead
