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Housing Conditions and Outdoor Air Pollution Together Affect Children’s Asthma Risk, New ECHO Study Shows

Posted on by Jodi Snare

Children growing up in homes with water damage or dampness and exposed to higher levels of outdoor air pollution during early childhood face a greater risk of developing asthma, according to new research supported by the NIH’s Environmental influences on Child Health Outcomes (ECHO) Program. The large multisite study found that early-life exposure to fine particulate matter (PM2.5) and indoor housing problems each independently raised asthma risk, while having a dog during infancy was linked to reduced risk.

Asthma affects millions of U.S. children, yet the environmental origins of the disease are complex. While previous research has tended to study exposures such as pollution or indoor allergens separately, this study shows that evaluating them together offers a more accurate picture of children’s risk. The ECHO Program, which brings together data from diverse U.S. populations, made this integrated analysis possible.

Drawing on data from 6,413 children across nine U.S. ECHO Study Sites, the research provides one of the clearest looks yet at how multiple early-life environmental factors interact to influence childhood asthma. The findings underscore the importance of assessing both indoor and outdoor environments together, rather than in isolation — an approach that prior studies often could not address due to limited sample sizes.

“Our research shows that to truly understand and prevent childhood asthma, we need to look at a child’s full environment—both the air they breathe outside and the conditions inside their home,” said Akihiro Shiroshita, a study author from Vanderbilt University School of Medicine. “Considering these factors together gives us a much clearer picture of what puts children at risk and how we can better protect them.”

Key Findings

  • Outdoor air pollution matters: Higher early life exposure to PM2.5 was associated with increased asthma risk.
  • Indoor environments matter too: Home dampness or water damage independently raised asthma risk, even after accounting for pollution exposure.
  • Pets may offer protection: Having a dog in the home during infancy was linked to a lower risk of developing asthma.
  • Large, diverse dataset: The study combines data from multiple U.S. ECHO Study Sites, offering a comprehensive view of environmental impacts on children’s respiratory health.

Researchers evaluated children’s exposure to PM2.5 during the first three years of life and combined that information with detailed data on early life housing conditions — including water damage, dampness, pet exposure, and dust mites. Childhood asthma was identified based on caregiver reports or physician diagnosis between birth and age five. The analysis also controlled for family and neighborhood factors to isolate the effects of environmental exposures.

The findings signal the need for additional research into how indoor and outdoor exposures interact and how early life interventions could help reduce asthma risk in children nationwide.

This collaborative research was published in Environmental Epidemiology.

About ECHO
The ECHO Cohort Consortium is a research program supported by the National Institutes of Health (NIH) with the mission to enhance the health of children for generations to come. ECHO Cohort investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

Media Contacts

For information or to request an interview, contact Rebekah Yeager,  rebekah.yeager@nih.gov.

If you are not a member of the media, but have a general inquiry, please contact  NIHKidsandEnvironment@od.nih.gov.

Connect With Us

echo connector

Check out the recent issues of our bi-monthly newsletter, the ECHO Connector, for program news and the latest research findings.

To receive the ECHO Connector through email, subscribe here.

Follow the ECHO Program on LinkedIn and X for the latest updates.

Exposure to Certain Flame-Retardant Chemicals During Pregnancy Associated with Child Cognition

Posted on by Jodi Snare

Exposure to certain organophosphate esters (OPEs)—chemicals commonly used as flame retardants and plastic softeners in a variety of household and industrial products—during pregnancy was associated with slightly lower scores on tests of mental skills in young children, according to a new ECHO Cohort study led by Akhgar Ghassabian, MD, PhD of New York University Grossman School of Medicine.

Previous studies have suggested that OPEs may affect child brain development. With increasing human exposure to these chemicals, especially during sensitive periods like pregnancy, there has been concern about the potential impact on child cognitive development. This study included data from 831 mother-child pairs from three ECHO Cohort Study Sites in the United States. When pregnant women had higher urine levels of diphenyl phosphate (DPHP), a compound produced during the breakdown of certain OPEs in the human body, their children tended to have slightly lower scores on tests of mental skills at ages 4–6. This pattern was seen in boys and girls. Unexpectedly, boys whose mothers had higher levels of certain other chemicals linked to OPE exposure during pregnancy scored higher on these tests, but this was not true for girls.

“Results from this study suggest that OPE exposure during pregnancy may be associated with minor decreases in cognitive functioning in offspring,” said Dr. Ghassabian. “Considering that DPHP is a widely detected OPE metabolite in the U.S. population, the overall population impact of this modest effect size can be significant.”

Additional studies could help researchers better understand the biological pathways underlying these associations. Additional studies could also help clarify the association between some chemical markers of OPE exposure and higher cognitive scores among boys.

This collaborative research, titled “Prenatal exposure to organophosphate ester flame retardants and child cognition: findings from the Environmental influences on Child Health Outcomes cohort,” is published in Environmental Pollution. Read the research summary.

Prenatal and Early-Life Pollution Exposures May Influence Childhood Blood Pressure Patterns, ECHO Study Finds

Posted on by Jodi Snare

A child’s blood pressure may be influenced by exposure to air pollution before and shortly after birth, according to a new study from the NIH-funded Environmental influences on Child Health Outcomes (ECHO) Program. The study focused on fine particulate matter (PM2.5) and nitrogen dioxide (NO2), common pollutants from vehicles, power plants, and other industrial sources.

High blood pressure in children is becoming more common worldwide and can lead to long-term health problems, including heart disease and impaired kidney function. Over the past two decades, childhood hypertension has increased by nearly 80 percent, particularly in countries with higher obesity rates, such as the United States. Because the roots of adult hypertension often begin in childhood, ECHO researchers examined whether early exposure to outdoor air pollution may influence blood pressure in children.

Air pollutants such as PM2.5 and NO2 are known contributors to cardiovascular disease in adults, but their effects on children’s blood pressure are less well understood. Previous studies have produced mixed results and were often limited to single locations. This ECHO study leveraged data from multiple cohort sites across the United States to better clarify these associations.

Researchers analyzed data from 4,863 children ages 5 to 12 from 20 ECHO Cohort Study Sites. They estimated outdoor air pollution exposure at participants’ home addresses during each trimester of pregnancy, across the full pregnancy, and during the child’s first two years of life. Children’s blood pressure was measured during study visits and compared with typical values for children of the same age, sex, and height. Blood pressure was considered high if it fell within the top 10 percent of these values.

Key Findings

  • PM2.5 exposure and higher blood pressure: Children who were exposed to higher levels of PM2.5 before and after birth had higher blood pressure on average between ages 5 and 12.
  • Early pregnancy as a sensitive period: Higher PM2.5 exposure during the first trimester was associated with a more pronounced systolic blood pressure and a greater likelihood of high blood pressure in childhood, indicating that early pregnancy may be a particularly sensitive period.
  • Unexpected findings for NO2: Higher maternal exposure to NO2 during pregnancy was associated with slightly lower blood pressure in children. This association was strongest during mid- to late pregnancy, particularly the second trimester, and was not linked to an increased risk of high blood pressure.
  • Timing matters: The results suggest that the timing of pollution exposure during pregnancy may be important for understanding its impact on children’s cardiovascular health.

“These findings add to growing evidence that early-life exposure to fine particulate air pollution may affect children’s cardiometabolic health, even at relatively low levels,” said study author Yu Ni, PhD, of San Diego State University. “The unexpected findings related to nitrogen dioxide suggest that more research is needed to understand how this type of air pollution may affect children’s developing bodies, as well as whether other environmental factors could be playing a role, such as transportation noise.”

This collaborative research was published in Environmental Research.

Media Contacts

For information or to request an interview, contact Rebekah Yeager,  rebekah.yeager@nih.gov.

If you are not a member of the media, but have a general inquiry, please contact  NIHKidsandEnvironment@od.nih.gov.

Connect With Us

echo connector

Check out the recent issues of our bi-monthly newsletter, the ECHO Connector, for program news and the latest research findings.

To receive the ECHO Connector through email, subscribe here.

Follow the ECHO Program on LinkedIn and X for the latest updates.

Exposure to Certain PFAS Associated with Maternal Depression & Stress for Pregnant and Postpartum Mothers, ECHO Study Finds

Posted on by Jodi Snare

Exposure to certain per- and polyfluoroalkyl substances (PFAS)  was associated with changes in depression and stress for pregnant and postpartum mothers, according to a new ECHO Cohort study led by Susanna Mitro, PhD and Lyndsay Avalos, PhD, MPH of Kaiser Permanente Northern California.

PFAS are a large, complex group of synthetic chemicals found in some household products such as cookware and stain-resistant fabrics. These substances are often referred to as “forever chemicals” because they don’t break down easily, causing them to build up over time in water, soil, and air. Previous studies have shown that PFAS can negatively affect the brain, and there is conflicting evidence about their potential effects on depression and perceived stress during and after pregnancy. This study included 4,403 pregnant participants from 16 ECHO Cohort study sites across the United States. Researchers measured the levels of seven PFAS in the mother’s blood during pregnancy, and participants reported on their depression and stress symptoms before and after giving birth.

Key Takeaways include:

  • Higher levels of N-methyl perfluorooctane sulfonamido acetic acid (N-MeFOSAA) were associated with slightly higher depressive symptoms and perceived stress, especially postpartum, while higher perfluorodecanoic acid (PFDA) levels were associated with a lower risk of diagnosed depression and lower prenatal perceived stress.
  • Exposure to perfluorooctanesolfonic acid (PFOS) showed a mixed pattern where moderate exposure was associated with increased depression risk, but the highest exposure was associated with lower depression risk.
  • When looking at all seven PFAS types as a group, there was generally no strong link to depression diagnosis or severity, but the data did show higher stress at low to moderate exposures, but lower stress as high exposure.
  • The effects of PFAS were different depending on social factors. For example, people who were not born in the U.S. or who had higher social vulnerability sometimes showed stronger links between PFAS and depression or stress.

“This study adds to mounting evidence that PFAS exposure during pregnancy may have negative health impacts on the pregnant individual, reinforcing the importance of minimizing exposure to PFAS during this sensitive time,” said Dr. Mitro.

Overall, the associations observed in this study were small, so more research is needed to fully understand the effects of PFAS on pregnancy mental health. Future studies could also help researchers clarify the biological mechanisms linking PFAS exposure to depression and stress and explore the role of social factors in influencing these associations.

This collaborative research, titled “Gestational PFAS concentrations in association with maternal depression and perceived stress during pregnancy and postpartum in the ECHO cohort,” is published in Environmental Research.

Pregnancy Stress Can Influence Relationship Between Chemical Exposures & Birth Outcomes, ECHO Study Finds

Posted on by Jodi Snare

Stress, anxiety, and depression during pregnancy and maternal adverse childhood experiences may influence the relationship between certain chemical exposures and birth outcomes, according to a new ECHO Cohort study led by Stephanie Eick, PhD, MPH and Anne Dunlop, MD, MPH of Emory University.

Most previous research on the effects of chemical exposures on birth outcomes has focused on a small number of well-established chemicals, such as bisphenol A (BPA) and certain phthalates. However, there are over 350,000 chemicals registered for global use, and the impact of many emerging or understudied chemicals on birth outcomes is not well understood. Additionally, prior studies have not adequately considered how different kinds of maternal stress (such as anxiety, depression, and adverse childhood experiences) might influence the effects of chemical exposures during pregnancy.

This study included 1,556 mother-child pairs from eleven ECHO Cohort Study Sites across the United States. Researchers analyzed urine samples from pregnant participants for 113 different chemicals from 10 chemical classes. Participants also reported on their stress, depression, anxiety, and adverse childhood experiences, allowing researchers to evaluate how these factors affect the relationship between different chemical exposures and birth outcomes.

Key Takeaways include:

  • Exposure to chemicals found in certain consumer and industrial products (such as phthalates, bisphenols, and insecticides) was associated with shorter pregnancies among women who experienced anxiety during pregnancy or in the early postpartum period.
  • Depression modified how exposure to certain chemicals (such as phthalates, parabens, and insecticides) affected birthweight and length of pregnancy.
  • Some chemicals positively correlated with length of pregnancy (duration) for mothers with more depression, while others were associated with lower birthweights when mothers had more depression symptoms.
  • The effects of a mother’s stress on the relationship between chemical exposures and birth outcomes depended on the type of chemical and type of stressor experienced.

“These findings suggest that screening for depression and anxiety during pregnancy could help identify women who may be at a higher risk of adverse birth outcomes,” said Dr. Eick.

Additional studies looking at the combined effects of multiple combined exposures could help researchers better understand the role of these factors in influencing birth outcomes. Future research could also further investigate potential biological effects of maternal adverse childhood experiences.

This collaborative research, titled “Psychosocial Stressors as Modifiers of the Associations Between Well-Studied and Understudied Chemicals and Birth Outcomes in the ECHO Cohort,” is published in Environmental Pollution.

Read the research summary.

Community Gun Violence Linked to Poorer Child Health, ECHO Study Finds

Posted on by Jodi Snare

Children living in neighborhoods with high levels of gun violence were 20% less likely to be reported in excellent or very good health compared with children in areas with lower levels of gun violence, according to a new study from the ECHO Cohort. The association was consistent across age groups and especially pronounced in high-poverty neighborhoods, where children exposed to gun violence were 23% less likely to be reported in excellent health.

The study included more than 13,450 children from birth to age 17 from 56 ECHO Cohort Study Sites across the United States. Researchers linked data on neighborhood gun violence, collected from the Gun Violence Archive, with parent-reported child health measures, while accounting for individual and neighborhood sociodemographic factors.

“This research highlights the profound impact of gun violence on the well-being of children, underscoring the critical importance of community-level violence prevention efforts and policies in fostering safer and healthier communities,” said study author Nandita Somayaji, MHS, MEd, of the Bloomberg School of Public Health at Johns Hopkins University.

These findings point to the importance of gun violence prevention strategies that can create safer environments for children.

This collaborative research titled “Associations between neighborhood-level gun violence and child general health status: An ECHO Cohort analysis” was published in Injury.

ECHO Symposium 2025: Slides and Full Videocast Now Available

Posted on by Jodi Snare

On September 15, 2025, the NIH Environmental influences on Child Health Outcomes (ECHO) Program hosted its inaugural ECHO Symposium: Translating Science to Action on the NIH campus in Bethesda, Maryland, and online. This free, one-day event brought together more than 1,000 researchers, clinicians, policymakers, advocates, community leaders, and families to explore how early environmental factors influence child health—and how to translate science into meaningful action.

The symposium featured a keynote address by Dr. Susan Kressly, President of the American Academy of Pediatrics; opening remarks by Dr. Matt Gillman, Director of the NIH ECHO Program, and former ECHO Cohort participant Jadine Benjamin; and a closing address by Dr. Michael Warren, Chief Medical and Health Officer of the March of Dimes.

Across three sessions—Chemical Exposures, Social and Neighborhood Factors, and Community Experiences—speakers highlighted research and perspectives on topics such as replacement chemicals and child health, environmental exposures in pregnancy, childhood trauma and toxic stress, neighborhood opportunity, media use, Indigenous community health, rural pediatric research, and parent experiences in pediatric studies.

Watch the videocast and view the slides
Missed the event or want to revisit a session? The full videocast and presentation slides are now available:

Wildfire Smoke Exposure During Pregnancy Linked to Higher Risk of Preterm Birth, ECHO Study Finds

Posted on by Jodi Snare

Study highlights increased risk, especially in Western states and during intense smoke events

Exposure to wildfire smoke during pregnancy was associated with a higher risk of preterm birth, especially in the Western United States and during periods of intense or prolonged smoke, according to a study funded by the National Institutes of Health’s Environmental influences on Child Health Outcomes (ECHO) Program.

Wildfires are becoming more frequent and severe, raising concerns about their impact on public health. While previous studies suggested a link between wildfire smoke and preterm birth, ECHO’s research built on this by studying a diverse population from prospective cohort sites nationwide. Researchers also looked closely at the role of exposure intensity, duration, and timing.

“Our study adds to growing evidence that wildfire smoke is a concern for maternal and child health. Incorporating wildfire smoke considerations into prenatal care and public health guidance could help expecting parents protect themselves during smoke events, especially in areas where wildfires are common,” said Allison Sherris, PhD, of the University of Washington.

Researchers analyzed data from over 20,000 births between 2006 and 2020 at 30 study sites across the U.S. They matched daily levels of air pollution from wildfire smoke (fine particulate matter, or PM2.5) to each participant’s home address during pregnancy. They tracked both the average amount of smoke and the number of “smoke days,” as well as “smoke waves”—stretches of consecutive days with high smoke levels.

The team used statistical methods to compare pregnancies week by week and adjusted for many factors, including maternal age, race, ethnicity, neighborhood poverty, season of conception, birth year, and more.

Key Findings

  • Widespread Exposure: Nearly all pregnant participants (99.2%) experienced at least one day of wildfire smoke, with an average of 22 smoke days during pregnancy.
  • Preterm Birth Risk: The overall rate of preterm birth was 8.4%, with higher rates among Black (11.7%) and American Indian or Alaska Native (13.5%) participants compared to White (7.6%) and Asian, Native Hawaiian, or Pacific Islander (8.0%) participants.
  • Link Between Smoke and Preterm Birth: For every 1 microgram per cubic meter (µg/m³) increase in average wildfire PM2.5 during pregnancy, the odds of preterm birth increased by about 7%. The association was even stronger in the Western U.S., where wildfire smoke is more intense and frequent.
  • Intensity and Duration Matter: The risk of preterm birth was higher with more intense smoke and longer-lasting smoke events. The strongest associations were seen for mid-pregnancy exposure to lower levels of smoke and late-pregnancy exposure to high-intensity smoke days.
  • Critical Windows of Vulnerability: Certain periods during pregnancy—especially mid-pregnancy for lower-intensity smoke and late pregnancy for high-intensity smoke—were linked to the greatest risk increases for preterm birth.

“Preterm birth has strong implications for future child health. Better understanding of how to prevent preterm birth will pay off as a healthier population into the future,” said Catherine Karr, MD, PhD, of the University of Washington.

The study points to the need for more research on why some regions or groups may be more affected, how wildfire smoke combines with other risks like extreme heat, and which prevention strategies work best. It also highlights the importance of public health agencies and healthcare providers offering ways to help keep pregnant people safe during wildfire events.

This collaborative research was published in The Lancet Planetary Health.

About ECHO
The ECHO Cohort Consortium is a research program supported by the National Institutes of Health (NIH) with the mission to enhance the health of children for generations to come. ECHO Cohort investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

Media Contacts

For information or to request an interview, contact Rebekah Yeager,  rebekah.yeager@nih.gov.

If you are not a member of the media, but have a general inquiry, please contact  NIHKidsandEnvironment@od.nih.gov.

Connect With Us

echo connectorCheck out the recent issues of our bi-monthly newsletter, the ECHO Connector, for program news and the latest research findings.

To receive the ECHO Connector through email, subscribe here.

Follow the ECHO Program on LinkedIn and X for the latest updates.

PFAS Exposures During Pregnancy Not Significantly Associated with Child Behavior Issues

Posted on by Jodi Snare

Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy was not significantly associated with behavior issues in children, according to a new ECHO Cohort study led by Catherine Bulka, PhD of the University of South Florida and Rebecca Fry, PhD of the University of North Carolina, Chapel Hill.

PFAS are man-made chemicals used in some consumer and industrial products like cookware, stain-resistant fabrics, and foams used to fight fires. They are often referred to as “forever chemicals” because they don’t break down easily, causing them to build up in water, soil, and air. Previous findings on the effects of prenatal PFAS exposure on child behavior have been inconclusive due to small sample sizes, limited exposure variability, and differing measures of child behavior. This study included children from nine ECHO Cohort study sites across the United States, including 1,723 preschool-age children (1.9-5.9 years) and 627 school-age children (6-15 years). Researchers measured mothers’ PFAS exposure through blood samples collected during pregnancy (between 2- and 42-weeks’ gestation) and assessed children’s behavior using the Child Behavior Checklist (CBCL).

Key Takeaways include:

  • Most of the PFAS detected in pregnant mothers were not clearly linked to behavior problems in their children overall.
  • Children whose mothers had medium levels of exposure to perfluorohexane sulfonate (PFHxS) during pregnancy showed more emotional problems, like being easily upset or withdrawn, especially when they were preschoolers. This pattern was not seen at very high or low levels of PFHxS exposure.
  • There were no strong connections between PFAS exposure before birth and behavior problems when the children were older (school-age).
  • Looking at combined exposures to multiple PFAS also did not show any clear relationship with child behavior.

“While most PFAS showed no association with behavioral problems, some suggestive, non-linear relationships emerged, indicating that these exposures may influence neurodevelopment in complex and unexpected ways,” said Dr. Bulka.

Additional studies could help researchers assess the effects of PFAS exposure during the postnatal period, which may be a more relevant window for childhood brain development and behavioral issues. Also, as some PFAS are being phased out of consumer products and replacements are emerging, future studies could help researchers understand the potential effects of exposures to these newer replacement chemicals.

This collaborative research, titled “Prenatal Exposure to Per- and Polyfluoroalkyl Substances: Association with Child Behavior in the Environmental influences on Child Health Outcomes (ECHO) Cohort,” is published in Environment International.

Read the research summary.

ECHO Participants and Investigators Featured in The Washington Post

Posted on by Jodi Snare

The Washington Post recently featured the Environmental influences on Child Health Outcomes (ECHO) Program in a story on phthalates—chemicals commonly found in plastics and personal care products—and how they may affect babies’ development during pregnancy.

The article highlighted ECHO participants who are helping researchers understand how chemical exposures during pregnancy and throughout the life course may influence pregnancy outcomes and child health. ECHO participants Arica Nyamsi and Cassondra Perez shared a range of experiences with chemical exposures, from making significant lifestyle changes to expressing uncertainty and a need for clearer guidance.

Sheela Sathyanarayana, a professor of pediatrics at the University of Washington, explained that determining safe levels of phthalate exposure is challenging because individual health risks vary based on genetics and susceptibility.

The story also featured ECHO investigator Dr. Leonardo Trasande of NYU Grossman School of Medicine, who noted in the article:

“Endocrine-disrupting chemicals are one of the biggest global health threats of our time. And 2 percent of us know about it — but 99 percent of us are affected by it.”

Chemical exposures will be a focus at the ECHO Symposium: Translating Science to Action on September 15, 2025. During the first session, Dr. Trasande will discuss phthalate exposure in pregnancy and early childhood, focusing on the evidence, knowledge gaps, and opportunities to inform policies, practices, and programs. Mrs. Perez will also speak during the third session on her experience as an ECHO participant.

Learn more about ECHO’s ongoing research on chemical exposures. Also, review the full symposium agenda for details and register to attend this free event either in-person or virtually.