New studies add to the extensive body of research showing the many risks that lead poses to youngsters.
The association between lead exposure and children's IQ is well-documented, but these University of Pennsylvania studies revealed how lead affects children's stress responses and behavior.
One study found a significant association between lead exposure in early childhood and poorly regulated heart rate variability during a stress-triggering task in early adolescence. This suggests an abnormal ("dysregulated") stress response.
The findings have implications for heart health and overall growth and development, according to the study authors.
"The biological mechanisms underpinning the relationship between lead and physiological stress functionality are relatively unknown," study co-author Olivia Halabicky said in a university news release. She worked on the study while a doctoral student at the university's School of Nursing.
Dysregulated stress responses are associated with a range of health issues, including heart and metabolic diseases and impaired brain development.
"Understanding these relationships could help to develop interventions to target this biological mechanism and thereby reduce the harmful effects of lead exposure for children at greatest risk," said co-author Jianghong Liu, a professor in healthy transitions.
Liu is also director of a U.S. National Institutes of Health-funded project that follows more than 1,000 children in Jintan, China, to understand how lead exposure, nutrition and psychosocial factors affect their behavior.
In another study, Liu and colleagues found that lead in the blood of kids aged 11 to 12 in Philadelphia was associated with a greater risk of behavior problems and social struggles.
"These findings have potentially important implications for public health and environmental regulation as well as understanding biological mechanisms that link social inequality with health outcomes, especially in youth from low-income, urban areas," Liu said.
Both studies appear in the journal Environmental Research.
Children can come in contact with lead through chipping paint, dust from lead paint and old lead pipes. Exposure is more likely to occur in poorer communities.
The American Academy of Pediatrics explains how to protect children from lead exposure.
SOURCE: University of Pennsylvania, news release, April 11, 2022