Even relatively low levels of lead exposure may increase children’s likelihood of developing strep throat, according to a new study conducted by researchers at the University at Buffalo. The findings suggest that exposure levels below established public health intervention thresholds could still be associated with increased susceptibility to respiratory infections.
Researchers analyzed medical records and blood lead screening data from more than 13,000 children aged 14 and younger in Philadelphia, Pennsylvania. The study covered the period between 2010 and 2020 and examined the relationship between lead concentrations in children’s blood and clinical diagnoses of strep throat and croup.
The results showed that children with blood lead concentrations between 1 and 3.4 micrograms per deciliter had approximately 2.5 times the odds of receiving a strep throat diagnosis compared with children whose levels were below 1 microgram per deciliter. For children with concentrations of 3.5 micrograms per deciliter or higher, the odds were approximately 2.7 times greater.
The researchers also observed that higher blood lead concentrations were associated with more frequent strep throat diagnoses. However, they found no clear relationship between lead exposure and croup infections.
Even Low Lead Concentrations May Affect Children’s Immune Systems
The findings highlight potential health risks associated with childhood lead exposure, including concentrations below the threshold used by the Centers for Disease Control and Prevention (CDC) to guide public health action.
The CDC’s blood lead reference value is currently used to identify children with blood lead concentrations that warrant increased clinical attention and potential intervention. In this study, however, researchers observed an association with strep throat even among children whose blood lead concentrations were below that threshold.
According to the researchers, environmental lead exposure can interfere with the development and maturation of a child’s immune system, potentially increasing vulnerability to infectious respiratory illnesses. Although previous research has suggested that lead can affect immune function, scientific evidence connecting childhood lead exposure with specific respiratory health outcomes has remained inconclusive.
The new findings add to existing evidence linking environmental lead exposure with potential damage to the developing immune system. They also indicate that health concerns may emerge at exposure levels lower than established public health action thresholds.
Older Housing and Income Inequality Could Increase Lead Exposure Risks
The researchers also highlighted the role of housing conditions and socioeconomic inequalities in determining children’s exposure to environmental lead.
Marina Oktapodas Feiler, the study’s corresponding author and an assistant professor of epidemiology and environmental health at the University at Buffalo’s School of Public Health and Health Professions, said the research addresses health inequalities and structural challenges affecting residents of older cities, including Buffalo.
“This work is directly related to health inequities and structural barriers faced in many older cities, including Buffalo,” says Feiler. “Homes and other residences in these cities have historical lead paint that can chip, making dust and deteriorating windows specifically problematic.”
Older residential buildings can contain deteriorating lead-based paint, which may release contaminated dust and paint particles into living spaces. Children can be exposed to lead through contact with these materials, particularly when paint deteriorates or surfaces are disturbed.
Feiler also pointed to the disproportionate burden faced by renters and lower-income households, which may have fewer resources to address hazardous housing conditions.
“Renters and those of lower income are disproportionately affected as they cannot maintain the homes or make appropriate renovations which remove lead,” she added.
Study Highlights Need for Greater Attention to Childhood Lead Exposure
The study, titled Environmental lead exposure and clinical infectious respiratory disease in a sample of urban and disadvantaged children, was published in the Journal of Exposure Science and Environmental Epidemiology on September 19.
The research included contributions from Eva Odiko, Rebecca Stutz, Jing Nie and Heather K. Lehman. Odiko is a master’s student in epidemiology at the University at Buffalo, while Stutz graduated from the programme in May 2025. Nie is a research assistant professor in the Department of Epidemiology and Environmental Health. Lehman is a clinical associate professor in the Department of Pediatrics and division chief of allergy, immunology and rheumatology at the Jacobs School of Medicine and Biomedical Sciences.
While the study establishes an association between blood lead concentrations and strep throat diagnoses, it does not establish that lead exposure directly causes the infection. Nevertheless, the findings raise concerns about the potential effects of even relatively low levels of environmental lead exposure on children’s developing immune systems.
The researchers’ findings also highlight the importance of addressing lead hazards in residential environments, particularly in older housing and communities where economic barriers can make remediation more difficult.
Read More :