Lead is an environmental neurotoxicant that causes neurocognitive deficits and cardiovascular and metabolic disorders. It also disproportionately affects socially disadvantaged communities. The association between lead exposure and children’s IQ has been well studied, but few studies have examined the effects of blood lead on children’s physiological stress and behavior. Three Penn Nursing studies shed light on how lead can affect children and adolescents’ physiological stress and emotional/behavioral development.

Exposure to lead during childhood and adolescence is associated with a host of detrimental outcomes that persist into adulthood. Until now, however, few studies have tested the association between lead exposure and the physiological stress response, which in and of itself may act as a precursor to and/or underlying mechanism of detrimental health outcomes.

New evidence suggests that early childhood lead exposure is significantly associated with dysregulated heart rate variability during an induced stress task in early adolescence, indicative of a dysregulated stress response. These findings hold implications for cardiovascular health and overall growth and development.

“The biological mechanisms underpinning the relationship between lead and physiological stress functionality are relatively unknown,” says first-author Olivia M. Halabicky, who completed this work as a doctoral student at Penn Nursing. Dysregulated stress responses are associated with a host of health consequences including cardiovascular and metabolic diseases as well as impaired neurodevelopment and neurocognitive outcomes of general and higher-order cognition.

“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,” says senior-author and principal investigator Jianghong Liu, the Marjorie O. Rendell Endowed Professor in Healthy Transitions and the faculty director of Global Health Minor. Liu is also Director of the NIH-funded China Jintan Child Health Project, which follows more than 1,000 children in Jintan, China from pre-school into adolescence to understand the influence of exposure to environmental lead, nutrition, and psychosocial factors on their behavior.