The study drew on 289 children enrolled in the PROGRESS cohort in Mexico, a long-running birth cohort designed to examine how environmental exposures shape child health. Rather than relying on blood or urine samples, which capture only recent exposure, the researchers turned to deciduous teeth, the baby teeth that children naturally shed. Teeth grow in layers much like tree rings, and the dentine that forms during specific developmental periods locks in a chemical record of what circulated in the child’s bloodstream at the time. By segmenting dentine along growth lines, the team was able to retrospectively quantify arsenic exposure for every week from sixteen weeks before birth through fourteen weeks after birth, an unprecedented temporal resolution for an immunotoxicology study.

When the children returned for a follow-up visit around age four to five, the investigators measured serum levels of immunoglobulin G antibodies directed against six vaccine antigens: measles, mumps, and rubella from the MMR vaccine, and diphtheria, tetanus, and pertussis from the DTP series. These antibodies are the immune system’s memory of vaccination, the molecular shield that prevents re-infection, and their concentrations in blood are a standard benchmark of how well a vaccine has taken hold. The measurements were performed using a multiplexed Luminex bead-based immunoassay, a technique that allows all six antibody targets to be quantified simultaneously from a small serum sample.

The statistical challenge was considerable. Because arsenic exposure was estimated for thirty consecutive weeks, the researchers needed a method that could detect when in that timeline exposure mattered, not just whether it mattered overall. They employed Distributed Lag Non-linear Models, or DLNMs, a framework originally developed in environmental epidemiology for studying delayed and time-varying effects of air pollution and temperature. The models related log2-transformed dentine arsenic concentrations to log2-transformed antibody levels across every week of the perinatal period, while adjusting for the child’s age, maternal education, parity, and child sex. The log2 transformation means the reported effects can be read as the change in antibody level associated with a doubling of arsenic exposure during a given week.

The results converged on a single, well-defined period. A doubling of arsenic exposure in the window spanning one week before birth to six weeks after birth was associated with significantly lower anti-measles antibody levels, with an estimated effect of minus 5.62 on the log2 scale and a 95 percent confidence interval running from minus 8.39 to minus 0.83. The same perinatal window showed a significant association for anti-rubella antibodies, with an effect estimate of minus 3.85 and a confidence interval from minus 6.99 to minus 0.63. In practical terms, children with higher arsenic exposure in the weeks surrounding delivery carried measurably weaker antibody defenses against measles and rubella years later, even though their vaccinations occurred long after the exposure itself.

Just as telling was what the analysis did not find. Arsenic exposure during the perinatal window showed no significant association with antibody levels against mumps, diphtheria, tetanus, or pertussis. Nor did earlier or later periods of prenatal and early postnatal exposure produce significant signals for any antigen. This selectivity is biologically intriguing. It suggests that the immune pathways supporting long-term antibody maintenance against measles and rubella may be more sensitive to arsenic’s interference than those supporting the other four antigens, or that different vaccine antigens rely on differently timed developmental programs of B-cell and plasma-cell maturation that vary in their vulnerability to toxic insult.

The timing of the susceptible window makes biological sense. The weeks surrounding birth are a period of profound immunological transition. The fetus must shift from the sterile, maternally protected environment of the womb to an microbe-rich world, and neonatal immune cells are actively learning to distinguish threat from tolerance. Maternal antibodies transferred across the placenta are waning while the infant’s own antibody production is just beginning. Arsenic is known to disrupt immune signaling, generate oxidative stress, and interfere with methylation processes that regulate gene expression, and a toxic exposure during this delicate choreography could plausibly leave a lasting imprint on how well vaccine memory is established and maintained.

The researchers also probed whether the effects differed between boys and girls, or between children who were breastfed at one month postpartum and those who were not, since both factors can shape immune development and arsenic dynamics. They found no heterogeneity by either sex or breastfeeding status, indicating that the association between perinatal arsenic and reduced measles and rubella antibodies appears to operate similarly across these subgroups. That consistency strengthens the case that the finding reflects a general biological vulnerability rather than an effect confined to a particular subset of children.

The methodological innovation deserves particular attention. Traditional exposure assessment in environmental health has long been hampered by the difficulty of reconstructing what a person was exposed to years or decades earlier. Baby teeth offer a solution that is both retrospective and precise, and their use here demonstrates how naturally shed biomaterials can transform the study of developmental toxicology. Combined with the DLNM framework, which treats exposure timing as a variable to be mapped rather than averaged, the approach allowed the team to draw a temporal map of vulnerability with weekly resolution, something conventional single-biomarker studies simply cannot achieve.

The public health implications are significant. Measles remains one of the most contagious human pathogens, and even modest reductions in population-level antibody levels can erode herd immunity and fuel outbreaks, a concern made vivid by recent resurgences of measles in countries where the disease was once controlled. Arsenic contamination of groundwater affects an estimated hundreds of millions of people worldwide, and in regions such as Mexico, where the PROGRESS cohort is based, exposure often begins before birth. If the findings are confirmed in other cohorts, they would add vaccine-preventable disease susceptibility to the long list of harms attributable to early-life arsenic exposure, and they would sharpen the argument for reducing arsenic exposure among pregnant women and newborns, whether through water filtration, dietary interventions, or regulatory limits on contaminated sources. The study, funded by the National Institutes of Health and led by researchers at the Icahn School of Medicine at Mount Sinai together with collaborators at Mexico’s National Institute of Public Health and other institutions, was published open access, with the authors reporting no competing interests.

Subject of Research: Perinatal arsenic exposure and vaccine-specific antibody levels in children

Article Title: Susceptible perinatal windows to arsenic exposure and serum antibody levels in children

Article References: Scotti, A., India-Aldana, S., Martinez, M., Arora, M., McRae, N., Lamadrid-Figueroa, H., Quataert, S. A., Estrada-Gutierrez, G., Torres-Olascoaga, L., Téllez-Rojo, M. M., Wright, R. O., Jusko, T. A., & Colicino, E. (2026). Susceptible perinatal windows to arsenic exposure and serum antibody levels in children. Environmental Health. https://doi.org/10.1186/s12940-026-01331-6

Image Credits: AI Generated

DOI: 10.1186/s12940-026-01331-6

Keywords: arsenic exposure, perinatal window, vaccine antibodies, measles, rubella, immunotoxicology, baby teeth, dentine, PROGRESS cohort, DLNM, humoral immunity, environmental health

The research team set out to answer a question that has lingered at the margins of environmental health science for years. Animal experiments and cell studies have long indicated that lead can disrupt immune function, altering how immune cells respond to infection and how the respiratory tract handles invading bacteria and viruses. Epidemiological evidence in children, however, has been sparse and often limited to broad measures of general illness. By focusing specifically on clinically diagnosed infectious respiratory disease, conditions such as pneumonia, bronchitis, and other infections confirmed in medical settings, the new study provides one of the clearest pictures yet of how environmental lead exposure relates to real, documented illness in childhood.

The study population consisted of urban and disadvantaged children, a group chosen deliberately. Children in these settings face a constellation of overlapping risks: aging housing stock with deteriorating lead paint and lead-contaminated dust, proximity to traffic and industry, limited access to preventive healthcare, higher rates of crowding, and nutritional deficiencies that can themselves impair immunity. Disentangling the contribution of lead from this tangle of factors is one of the central methodological challenges of environmental epidemiology, and the researchers approached it with a battery of statistical adjustments designed to isolate the exposure of interest.

Technically, the investigators assessed lead exposure using biomarkers that reflect the body’s cumulative burden of the metal. Blood lead levels, the most common clinical measure, capture relatively recent exposure over the preceding weeks to months. Where available, the study also drew on measures that integrate exposure over longer periods, such as dentine lead levels in shed baby teeth, which record the lead a child absorbed during early development much as tree rings record growing conditions. Combining these biomarkers allowed the team to examine both contemporaneous and historical exposure, an important distinction because the immune consequences of lead may depend on when during development the exposure occurs.

Clinical infectious respiratory disease was identified through medical diagnoses rather than parental reports of symptoms, a design choice that reduces recall bias and anchors the outcome in verified healthcare encounters. The researchers then modeled the relationship between lead biomarkers and disease occurrence while accounting for a range of potential confounders, including household socioeconomic status, parental education, exposure to tobacco smoke, housing conditions, and other environmental co-exposures. The analytic strategy reflects a growing consensus in exposure science that single-pollutant models can be misleading in disadvantaged communities, where children are rarely exposed to one hazard at a time.

The results indicated that children with higher lead burdens experienced more clinically diagnosed infectious respiratory disease than their peers with lower exposures. While the observational design of the study cannot prove that lead caused the infections, the association persisted after adjustment for major confounding factors, and it aligns with a coherent biological story. Lead is known to interfere with several arms of the immune system. It can impair the function of macrophages, the scavenger cells that engulf bacteria and debris in the lung; it can alter the balance of T helper cell responses, shifting immunity away from patterns that effectively combat certain pathogens; and it can disrupt the production of antibodies and the integrity of epithelial barriers that line the airways. Any of these mechanisms, alone or in combination, could plausibly translate into increased susceptibility to respiratory infection.

The findings carry particular weight for immunology because they connect a ubiquitous environmental toxicant to a clinically meaningful outcome through mechanisms that laboratory science has already sketched out. In experimental systems, lead-exposed animals show diminished resistance to bacterial pneumonia and altered cytokine responses to viral challenge. Human studies have linked lead exposure with changes in circulating immune cell populations and reduced vaccine antibody titers in some contexts. The new study extends this evidence into the realm of everyday pediatric illness, suggesting that the immunological fingerprints observed in the laboratory may manifest as pneumonia and bronchitis diagnoses in children’s medical records.

For public health, the implications are sobering. Lead exposure remains far from a solved problem in many cities. Flint, Michigan, made headlines as an extreme case, but thousands of communities across the United States and around the world continue to grapple with lead in drinking water, soil, paint, and dust. Children in disadvantaged neighborhoods absorb disproportionately high exposures precisely because of the legacy of discriminatory housing and industrial siting policies. If lead additionally raises the risk of respiratory infections, then the true cost of these exposures extends beyond neurodevelopmental harm into the domain of infectious disease, a burden that falls on families, healthcare systems, and schools.

The study also arrives at a moment when respiratory infections have assumed renewed prominence in public consciousness. The COVID-19 pandemic demonstrated how sharply infectious respiratory disease can shape societies, and it highlighted the importance of understanding why some individuals, and some communities, suffer more severe outcomes than others. Environmental exposures such as air pollution have been implicated in worse COVID-19 outcomes, and the new lead findings fit into a broader picture in which the environments children inhabit quietly program the resilience of their immune systems. A child’s ability to fight off pneumonia may depend not only on nutrition, vaccination, and access to care, but also on the toxic legacy embedded in the dust on their windowsills.

Several questions remain open. The observational nature of the study means residual confounding cannot be excluded; unmeasured differences between more and less exposed children, such as healthcare access or viral exposure intensity, may contribute to the association. The dose-response relationship, the critical question of how much lead is needed to meaningfully alter infection risk, requires further quantification, particularly at the lower exposures now common in many countries. And the biological pathways in humans, rather than in animal models, remain to be fully characterized. Longitudinal birth cohorts that follow children from pregnancy through childhood, collecting repeated biomarkers and clinical outcomes, would be the natural next step.

Even so, the study strengthens the case for aggressive lead abatement as a respiratory health intervention, not merely a neurodevelopmental one. Replacing lead service lines, remediating lead paint in older housing, cleaning contaminated soils, and enforcing housing codes are interventions with well-established benefits for cognitive development. If they also reduce the incidence of childhood pneumonia and bronchitis, the health-economic calculus shifts further in favor of action. Every dollar spent removing lead from a child’s environment may return dividends not only in test scores and behavior, but in fewer nights in the emergency department, fewer courses of antibiotics, and fewer disrupted school years. In a sample of urban and disadvantaged children, the study reminds us that the environment they breathe and touch is inseparable from the immune defenses they carry within.

Subject of Research: The association between environmental lead exposure and clinically diagnosed infectious respiratory disease in urban and disadvantaged children.

Article Title: Environmental lead exposure and clinical infectious respiratory disease in a sample of urban and disadvantaged children

Article References: Odiko, E., Stutz, R., Nie, J., Lehman, H. K., Turella, J., Khan, A. I., & Feiler, M. O. (2026). Environmental lead exposure and clinical infectious respiratory disease in a sample of urban and disadvantaged children. Journal of Exposure Science & Environmental Epidemiology. https://doi.org/10.1038/s41370-026-00978-0

Image Credits: AI Generated

DOI: 10.1038/s41370-026-00978-0

Keywords: lead exposure, children's health, respiratory infection, environmental epidemiology, immunotoxicology, urban health, health disparities, blood lead levels, pneumonia, public health, toxicology, immune system