Grantee links early lead exposure with behavioral problems in children
DERT Success Story
Jianghong Liu, Ph.D.
NIEHS grantee Jianghong Liu, Ph.D., is working to understand how early exposure to lead can affect a child’s brain in a way that leads to emotional and behavioral problems.
“Scientists as well as society have traditionally viewed children’s behavior problems, such as anti-social behavior, as stemming from psychosocial factors rather than having a physiologic basis in the brain,” explained Liu, an associate professor at the University of Pennsylvania School of Nursing. “After Herbert Needleman’s 1996 landmark paper showing the effects of lead on juvenile delinquency, I became interested in lead as an early health factor that could shape the trajectory of brain development.”
Studying lead exposure in China
During her postdoctoral fellowship, Liu began to assemble a study cohort in Jintan, China, to see whether U.S. lead studies could be replicated there. In 2004, the study recruited 1,600 preschool children, and just over 1,200 are still being followed more than 10 years later.
Liu received a K01 Mentored Research Scientist Award from NIEHS in 2007 and gained valuable mentorship from Herbert Needleman, M.D., an NIEHS-funded researcher at the University of Pittsburgh. “This funding not only helped protect my research time, but also allowed me to gain additional training in environmental health research methods, collect pilot data, and build an interdisciplinary team that included neuroscientists and environmental health scientists.” Liu also received guidance from NIEHS grantee Linda McCauley, Ph.D., of the Nell Hodgson Woodruff School of Nursing at Emory University; McCauley was instrumental in mentoring her in using an epidemiological approach for studying how environmental toxicity affects children.
Liu’s subsequent K02 Independent Scientist Award and R01 Research Project Grant from NIEHS have helped move her research forward. In 2014, she published a paper in JAMA Pediatrics showing that blood lead concentrations measured in more than 1,300 preschool children from the China Jintan Child Cohort Study were associated with increased risk of behavioral and emotional problems, such as being anxious, depressed, or aggressive, at age 6. The investigators also found that as blood lead concentration increased, so did the risk of clinical-level behavioral problems, including internalizing disorders as well as anxiety and pervasive developmental problems.
The average blood lead level in the children was 6.4 micrograms per deciliter, which is above the new Centers for Disease Control and Prevention (CDC) action level of 5 micrograms per deciliter. The CDC action level was lowered because of the preponderance of studies showing that children with blood lead levels below the former cutoff level of less than 10 micrograms per deciliter were found to have associated IQ deficits, attention-related behaviors, and poor academic achievement. Liu’s work supports these findings, as well as the prevailing conclusion that there is no safe level of lead exposure.
Liu later published research showing that the children who ate breakfast regularly had lower blood lead concentrations than children who skipped breakfast. This work points to nutritional interventions as a possible prevention strategy to lessen the health effects from lead exposure. She also published findings from the cohort showing that sleep problems and fatigue are prevalent in Chinese kindergarten children and are associated with poor cognitive performance.
Liu continues to spend around three months each year in China collaborating with the maternal health center, Jintan hospital, and the Children Environmental Health Center at Shanghai Jiaotong University.
Supplementary NIEHS grants through the Summer Research Experiences for Students and Science Teachers Program have allowed Liu to bring small groups of nursing and pre-med students on these trips, where they have been involved in collecting data, helping conduct focus groups, and working at community health fairs.
“I am passionate about my research on environmental health of children,” said Liu. “I want my research to make a difference not just in the local community in China, but in communities around the world.”