Healthcare (Commonwealth Union) – Parents often worry about lead because of its well-known effects on a child’s learning and development. A new study suggests another possible concern: even small amounts in the blood may make children more likely to get strep throat.
The research comes from the University at Buffalo and was released on October 23, 2026. It was published on September 19 in the Journal of Exposure Science and Environmental Epidemiology.
What the researchers did
The team studied medical records for more than 13,000 children aged 14 or younger in Philadelphia, Pennsylvania, covering the years 2010 to 2020. They used routine blood lead tests, which are commonly done as a screening measure. They then checked the same records to see which children had been diagnosed with strep throat or with croup, another childhood respiratory illness.
What they found
The children were grouped by blood lead level, measured in micrograms per deciliter. Those with the lowest levels, under 1, served as the comparison group. That level is below the point at which public health officials step in.
Children with levels between 1 and 3.4 had about 2.5 times the odds of a strep diagnosis compared with that lowest group. Children at or above 3.5 had about 2.7 times the odds. The 3.5 mark is the threshold the U.S. Centers for Disease Control and Prevention (CDC) uses to prompt public health action.
In other words, the jump in risk appeared even among children whose lead levels were below that official trigger point. Higher lead levels were also tied to children being diagnosed with strep more often. The researchers found no clear link between lead and croup.
Odds is a statistical measure of how likely something is in one group compared with another. It is not the same as saying a child is 2.5 times as likely to get sick, but it does point to a meaningful difference.
Why it might happen
The researchers say lead exposure can interfere with how a child’s immune system develops and matures, which may leave children more vulnerable to respiratory infections. They also note that earlier evidence connecting lead to childhood breathing-related illness has been inconclusive, so this study adds to a picture that is still taking shape. It is also worth remembering that this type of study shows a link, not proof that lead directly causes strep throat.
The CDC’s 3.5 figure is a reference value that alerts doctors to watch a child more closely and consider steps to reduce exposure at home. According to the university, it is not a measure of what is safe. The new findings add to the evidence that effects can show up below it.
A problem tied to where people live
Marina Oktapodas Feiler, the study’s corresponding author, is an assistant professor of epidemiology and environmental health at UB’s School of Public Health and Health Professions. She said the findings relate directly to unequal health outcomes and the built-in obstacles that many older cities, Buffalo among them, continue to face.
She explained that homes in these cities often contain old lead paint, which can chip and create dust. Deteriorating windows are a particular trouble spot. She added that renters and lower-income families bear the heaviest burden, since they frequently lack the ability to maintain their homes or pay for the renovations that would get rid of lead.
What families can take from this
The study does not suggest that every child with a sore throat has lead exposure. Strep throat is a common bacterial infection and has many causes. But the findings strengthen the case for taking low-level lead seriously, particularly in older housing. As general guidance rather than part of the study, parents in homes built before lead paint was banned may want to ask a pediatrician about blood lead testing, and keep an eye on peeling paint and dusty window areas. Renters worried about conditions can also raise concerns with a landlord or local health department.
