Lead in kids' blood is linked with behavioral and emotional problems, reports new research, "Blood Lead Concentrations and Children’s Behavioral and Emotional Problems: A Cohort Study" ("NIH...Turning Discovery Into Health®: Blood lead levels and children's behavioral and emotional problems: a cohort study,") published online June 30, 2014 in the journal JAMA Pediatrics. Emotional and behavioral problems show up even with low exposure to lead, and as blood lead levels increase in children, so do the problems, according to research funded by the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health.
"This research focused on lower blood lead levels than most other studies and adds more evidence that there is no safe lead level," explained NIEHS Health Scientist Administrator Kimberly Gray, Ph.D, according to the June 30, 2014 news release, Lead in kids' blood linked with behavioral and emotional problems. "It's important to continue to study lead exposure in children around the world, and to fully understand short-term and long-term behavioral changes across developmental milestones. It is well-documented that lead exposure lowers the IQ of children."
Other studies have linked low levels of lead in the blood to reading problems in children. You also may wish to check out the Los Angeles Times news article, "Kindergarten reading problems may be due to lead poisoning."
Sacramento has too many kids with measurable levels of lead in their bloodstream
To better characterize lead poisoning among children at high risk for lead exposure in California, the California Department of Health Services (CDHS) conducted lead-screening surveys that measured lead levels in children's blood, household paint, and soil in three selected high-risk areas in northern, southern, and central California. There's a report from the CDC, "Blood Lead Levels Among Children in High-Risk Areas -- California, 1987- 1999," that summarizes the survey findings and describes CDHS's efforts to reduce lead exposure among children in California, especially among those in high-risk areas.
CDHS selected three areas for the surveys based on the likelihood that old housing in these areas contained lead paint (42%-72% of the housing in the survey areas was built before 1950): Oakland in Alameda County (1987); Wilmington and Compton in Los Angeles County (1988); and Sacramento in Sacramento County (1990). In the Oakland and Sacramento survey areas, CDHS attempted to enroll all households with children aged 12-59 months.
In the two communities in Los Angeles County, a systematic sample of every fourth block was selected, and CDHS attempted to enroll all households with children aged 12-59 months in those sample blocks. The proportion of eligible households agreeing to participate in each area included 358 (71%) of 506 in Oakland, 350 (56%) of 621 in Wilmington/Compton, and 232 (47%) of 495 in Sacramento. Overall, these households included 973 families with 1397 children in the target age range (ages of children were equally distributed).
In Oakland, initial blood lead testing was performed by collecting capillary blood samples from the children. To reduce the possibility of sample contamination caused by lead on children's hands, their hands were vigorously washed before the capillary sample was obtained; a confirmatory venous sample was obtained from 74% of the Oakland children with an initial capillary BLL greater than or equal to 15 ug/dL. In Wilmington/Compton and Sacramento, venous blood samples were collected from 96% of the participating children; capillary samples were collected from the other 4% of children surveyed.
In Oakland and Wilmington/Compton, household paint samples were collected only when peeling or chipping paint was observed; in Sacramento, paint samples were collected from surfaces regardless of condition. At each household, soil samples of the top inch of soil were collected from one to five locations, (for example, the midsection of front, back, and side yards; directly beneath a rain drain; and near a building not attached to the house on the household property.) Soil lead level was defined as the geometric mean of all samples collected at the household. Paint lead levels reported were the maximum level found at a home. Lead content in blood and environmental samples was measured using graphite-furnace atomic-absorption spectrophotometry.
In these three areas, 40%-84% of children were Hispanic and members of families with reported annual family incomes of less than $15,000. BLLs of greater than or equal to 10 ug/dL were detected in 67% of children in Oakland, 32% in Wilmington/Compton, and 14% in Sacramento. BLLs greater than or equal to 20 ug/dL were detected in 5% of children in Oakland, 4% in Wilmington/Compton, and 1% in Sacramento.
Geometric mean lead levels in household paint were highest in Oakland and lowest in Wilmington/Compton (range for exterior paint: 3100-13,545 parts per million (ppm)) (Table 1). In all three areas, exterior surfaces were substantially higher in paint lead levels than were interior surfaces. However, lead levels for some interior paint samples exceeded 5000 ppm (37% in Oakland, 25% in Sacramento, and 13% in Wilmington/Compton). Soil lead levels were highest in Oakland where 46% of household soil lead levels exceeded 1000 ppm.
Blood lead concentrations were associated with increased risk of behavioral and emotional problems, according to the new 2014 study, "Blood Lead Concentrations and Children’s Behavioral and Emotional Problems: A Cohort Study"
Blood lead concentrations measured in more than 1,300 preschool children in China were associated with increased risk of behavioral and emotional problems, such as being anxious, depressed, or aggressive. The average blood lead level in the children was 6.4 micrograms per deciliter.
While many studies to date have examined health effects at or above 10 micrograms per deciliter, this study focused on lower levels. The CDC now uses a reference level of 5 micrograms per deciliter, to identify children with blood lead levels that are much higher than normal, and recommends educating parents on reducing sources of lead in their environment and continued monitoring of blood lead levels.
"Young children are particularly vulnerable to the toxic effects of lead, because lead can affect children's developing nerves and brains," said senior author Jianghong Liu, Ph.D., according to the June 30, 2014 news release, Lead in kids' blood linked with behavioral and emotional problems. Liu is with the University of Pennsylvania School of Nursing, Philadelphia.
Lead is a naturally occurring toxic metal, but sources of lead exposure are often due to human activities, including burning fossil fuels, mining, and manufacturing. In the United States, lead exposure usually comes from lead-containing products, such as paint, caulking, and pipe solder, in older homes. In China, lead exposure is more often related to air pollution.
In the United States, blood lead concentrations increase with age in children up to 2-3 years old and then decline
"The sources of lead exposure may explain why concentrations of lead are different," explained Liu, according to the news release. "In China, we found that blood lead concentrations increased with age in preschool children. In the United States, however, blood lead concentrations increase with age in children up to 2-3 years old and then decline."
For the study, the researchers analyzed one blood sample taken from each child between the ages of 3-5. Behavioral problems were assessed at age 6 using standardized questionnaires. The questionnaires were filled out by the children's teachers and parents, which the authors noted is both a strength and limitation. "The study used scores from two sources, but the ratings do not provide a clinical diagnostic measure of behavioral problems," said Liu.
U.S. studies have reported that lead exposure causes what psychologists call externalizing behavior problems, such as aggressiveness and bullying, which may lead to truancy and even jail time as children get older
In this study, children with higher blood lead levels had internalizing problems, such as anxiety and depression, as well as some externalizing problems. Though not addressed in this study, Liu said these differences could be explained by cultural, genetic, or environmental variations, or research gaps.
The authors emphasized according to the news release, "Continuing monitoring of blood lead concentrations, as well as clinical assessments of mental behavior during regular pediatric visits, may be warranted." Authors of this 2014 study are Liu J, Liu X, Wang W, McCauley L, Pinto-Martin J, Wang Y, Li L, Yan C, and Rogan WJ.
The NIH/National Institute of Environmental Health Sciences (NIEHS) supports research to understand the effects of the environment on human health and is part of NIH. For more information on environmental health topics, visit the NIH.gov website.You also can subscribe to one or more of the NIEHS news lists to stay current on NIEHS news, press releases, grant opportunities, training, events, and publications.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit the NIH website.
Can omega-3 fatty acids help reduce hyperactivity in children on the autism spectrum?
In another recent study, "Internet-Based, Randomized, Controlled Trial of Omega-3 Fatty Acids for Hyperactivity in Autism," published online in the June 2014 issue of the Journal of the American Academy of Child and Adolescent Psychiatry, the research team concluded that omega-3 fatty acids did not lead to a statistically significant reduction in hyperactivity.
The first pediatric autism study now has been conducted entirely online. The University of California - San Francisco (UCSF) shows success of randomized clinical trial for kids with autism, establishing it as a time and cost effective tool. UC San Francisco researchers have completed the first Internet-based clinical trial for children with autism, establishing it as a viable and cost effective method of conducting high-quality and rapid clinical trials in this population.
There also are other articles about children's nutrition, autism, and hyperactivity online to ponder such as, "10 Ways to Help Reduce Hyperactivity in Children with ADHD," and "Special diets for Autism, PDD and ADHD - Treat Autism." For example, hunger and blood sugar peaks and valleys can influence how hyperactive a child may act. Or see, "Autistic Children Requirements for Diet Changes" and "For 64 Percent of Kids with ADHD, Food is the Cause."
In their study, "Internet-Based, Randomized, Controlled Trial of Omega-3 Fatty Acids for Hyperactivity in Autism," the researchers looked at whether an Internet-based trial was a feasible way to evaluate whether omega-3 fatty acids helped reduce hyperactivity in children with autism. The authors found that not only was it a valuable platform for conducting the randomized clinical trial, but that it was both cost and time effective, as well.
"Recruitment for clinical trials in children with autism is one of the biggest challenges we face in studying potential treatments, and we found that process to be accelerated and streamlined by using existing online communities for enrollment," said lead author Stephen Bent, according to the June 30, 2014 news release, "First pediatric autism study conducted entirely online." Bent is an associate professor of medicine at UCSF. "This trial can serve as a model for how to efficiently test potential treatments through the growing power of online communities."
You also may wish to take a look at the abstract of another study, "Biological Overlap of Attention-Deficit/Hyperactivity Disorder and Autism Spectrum Disorder: Evidence From Copy Number Variants," published online in the July 2014 issue of the Journal of the American Academy of Child and Adolescent Psychiatry.
Using the Interactive Autism Network's (IAN) robust online community of parents, the researchers enrolled 57 children from 28 states into the randomized trial
In the study on omega-3 fatty acids and hyperactive children who also are on the autism spectrum, the researchers enrolled children were randomly assigned to either receive 1.3 grams of omega-3 fatty acids or an identical placebo daily for six weeks. Once a week the participants' parents received an email asking them to complete outcome measures on how their child was doing and report on the child's level of hyperactivity. The children's teachers reported on changes in hyperactivity as well. The parent and teacher responses were submitted to a database, allowing the researchers to access the data immediately.
Because the IAN requires that parents complete a short questionnaire and verify that their child has been professionally diagnosed in order to participate in the online network, the researchers were able to confirm the participants met the diagnostic criteria for autism without a clinic visit.
While the researchers found that the omega-3 fatty acids did not lead to a statistically significant reduction in hyperactivity, they concluded the online trial was a promising technique for evaluating treatments for autism
"The entire study was completed in slightly more than three months from the start of enrollment, and demonstrates there are many advantages including low cost, rapid enrollment, high completion rate, convenience for participating families, and the ability to participate from virtually any location," said Bent, according to the news release. "We had 100 percent completion of all outcome measures from parents and teachers, indicating that there is an ease to this method of testing that engages parents at a higher rate than traditional trials."
A grant from the Simons Foundation and by the National Center for Research Resources and the National Institute of Health supported the study. Other authors of the study are senior author Paul Law, MD, Tara Zandi, MSW, Kiely Law, MD, Luther Kalb, MHS, and Jay Nestle, BS, all of the Kennedy Krieger Institute and Robert Hendren, PhD, Jae-Eun Choi, BA, and Felicia Widjaja, MPH, of the University of California, San Francisco.