Harsh Parenting and High Socioeconomic Stress May Be Associated with Higher Internalizing Problems Like Anxiety in Children, ECHO Study Finds

Authors: Lue Williams, Veronica Oro, Leslie Leve, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Internalizing problems in childhood such as chronic internal distress may be early indicators of problems associated with disorders such as depression and anxiety. Internalizing by children can be influenced by biological and environmental factors, including parent-child relationships and socioeconomic status.

This study examined the relationship between two early childhood stress factors, harsh parenting and socioeconomic stress, and children’s development from childhood through adolescence. For this study, the researchers characterized harsh parenting, or “parental hostility” as non-supportive and controlling parenting practices, displays of anger and disappointment in children, and discipline through punishment. Socioeconomic stress reflects disadvantages associated with factors like household income. Few studies have examined early childhood predictors of internalizing behavior development, so this research fills an important gap by examining the role of diverse risk factors in early life, between the ages of 18 months and 5 years, on patterns of internalizing symptoms later in childhood. The study design, which used data collected from participants over a long period, also allowed the research team to explore the long-range impact of early life influences across critical stages of children’s physical, social, and psychological development.

What were the study results?

Researchers observed that, within the study sample, children fell into three main groups based on the severity of their internalizing behaviors and how those behaviors progressed with age: low, moderate-increasing, and higher-increasing. Some of the internalizing behaviors reported include feeling anxious or depressed, being withdrawn, and complaining of aches and sickness. Parents who reported more negative interactions with children in early childhood had children who were more likely to be in the group with the highest internalizing behaviors. Children with more socioeconomic stress in their households were also most likely to be in the highest internalizing behaviors group, as compared with both the low- and moderate-internalizing symptoms groups.

Researchers also observed that household socioeconomic stress directly predicted children’s mental health. Study investigators did not find any significant relationship between child sex assigned at birth and how likely they would be to show internalizing behaviors.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was this study's impact?

The findings from this study suggest that in addition to focusing on children’s symptoms when treating internalizing problems, health service providers may also wish to consider the broader context of caregiver behavior and access to resources for care.

Who was involved?

The study included two samples—a nationwide sample of 481 children who were adopted at birth and a sample of 1,053 children from six predominantly low-wealth, rural communities in eastern North Carolina and central Pennsylvania. Adopted children from the Early Growth and Development Study (EGDS) have lived in their adoptive homes since birth and were recruited into the study between 2003 and 2009. Children from the Family Life Project (FLP) were raised by their biological parents and were recruited into the study at birth, between September 2003 and 2004. Results may not be representative of the general population.

What happened during the study?

The researchers analyzed data collected from children and families that participated in the EGDS and FLP. EGDS children and families completed assessments approximately every nine months when adoptees were under the age of 3, and every one to two years after that. FLP participant families completed an initial home visit assessment when children were 2 months old and participated in annual assessments thereafter.

What happens next?

Future studies are needed to further support programming and research efforts by exploring mechanisms that underlie the relationship between socioeconomic stress, parenting styles, and children’s internalizing behaviors identified in the current study.

Where can I learn more?

Access the full journal article, titled “Influence of Early Childhood Parental Hostility and Socioeconomic Stress on Children’s Internalizing Symptom Trajectories from Childhood to Adolescence,” in Frontiers in Psychiatry.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published April 16, 2024

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Harsh Parenting and High Socioeconomic Stress May Be Associated with Higher Internalizing Problems Like Anxiety in Children, ECHO Study Finds

ECHO Study Suggests Living Near Green Space Is Associated with Lower Anxiety and Depression in Preschool-Age Kids

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ECHO Study Suggests Living Near Green Space Is Associated with Lower Anxiety and Depression in Preschool-Age Kids

Authors: Nissa Towe-Goodman

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

While previous research has suggested that access to nature is important for mental health, there are a limited number of studies that have examined these effects on young children. ECHO investigators addressed this research gap by looking at whether exposure to green space was associated with internalizing symptoms (e.g., anxiety, depression) and externalizing symptoms (e.g., aggression, rule-breaking) among children.

What were the study results?

The ECHO researchers found that higher levels of green spaces, up to three-fourths of a mile from a child’s home, were linked with lower symptoms of anxiety and depression from ages 2 to 5. Although green space was also linked with symptoms of aggression and rule-breaking in early childhood, this association was reduced after accounting for factors such as poverty levels, unemployment, and housing costs. Researchers found no significant association between residential green space and internalizing or externalizing symptoms in middle childhood, ages 6 to 11.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was this study's impact?

Most research evaluating the effect of green space on health so far has been limited in children and studied one or a few cities at a time. ECHO Program researchers were able to examine data from children in 199 counties across 41 U.S. states, exploring the connection between exposure to green spaces from birth and anxiety, depression, aggression, and other symptoms during early or middle childhood. These findings suggest that green initiatives such as parks, urban forest programs, or protected natural areas may influence early emerging anxiety and depression symptoms.

Who was involved?

The 2,103 children included in the study were born between 2007 and 2013 and ranged in age from 2 to 11, spanning early and middle childhood.

What happened during the study?

Researchers analyzed information from parents who completed the Child Behavior Checklist for their children from ages 2 to 11 and combined this data with the family’s residential address since the child was born and satellite-based imagery of vegetation density around their homes. Green space exposure was measured using the Normalized Difference Vegetation Index (NDVI), a widely used metric for quantifying vegetation density using sensor data. NDVI values range from -1 to 1. High NDVI values (approximately 0.6 to 0.9) represent dense vegetation, such as forests; values approaching 0 represent areas without live vegetation.

What happens next?

Future studies can explore the types of natural areas linked with early mental health and examine the role of green space around schools. Investigating how early exposure to nature influences mental health into adolescence and adulthood could also be an important area to study.

Where can I learn more?

Access the full journal article, titled “Green space and internalizing or externalizing symptoms among children,” in JAMA Network Open.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published April 10, 2024

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ECHO Study Suggests Living Near Green Space Is Associated with Lower Anxiety and Depression in Preschool-Age Kids

Study Finds Link Between Phthalate Exposure During Pregnancy and Development of Multiple Health Outcomes in Children

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Study Finds Link Between Phthalate Exposure During Pregnancy and Development of Multiple Health Outcomes in Children

Authors: Drew Day, Kaja Z. LeWinn, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Chronic health conditions, such as asthma and obesity, can develop together during childhood but are usually studied separately. ECHO researchers used new machine learning tools to explore patterns of health outcomes in children and then looked at how common exposures are associated with multiple health conditions.

The goal of this study was to use data from ECHO Cohort research sites across six U.S. cities to characterize “clusters,” or patterns of obesity-related, lung health, and brain development outcomes in children and to investigate how these patterns relate to mothers’ exposures to chemicals called phthalates during pregnancy. Phthalates are chemicals widely used in plastics, and maternal exposure to certain phthalates have been linked to preterm birth.

What were the study results?

The researchers identified three groups of children with a pattern of health outcomes that occurred together:

A group of relatively healthy children;
A group of children with lower IQ, elevated obesity,
and slightly elevated asthma-related outcomes such as asthma, wheezing, and allergies; and
Another group of children with high asthma-related outcomes along with elevated obesity and some increase in anxiety- and depression-related outcomes.

Compared to children in the healthy group, other groups had more male children, mothers with higher BMI and lower education attainment, and lower household incomes. The researchers found that children—particularly boys—were more likely to be in the third group if their mothers were exposed to phthalates during pregnancy.

What was this study's impact?

These findings suggest that exposure to phthalates during pregnancy might be associated with an increased risk of developing not only asthma and related lung outcomes, but also obesity and mental health issues such as anxiety and depression. This study also suggests that low-income households are at higher risk for worse childhood health outcomes.

The three patterns of health outcomes seen in this study also reveal more about how pediatric diseases might arise together, which could help inform future research on what biological processes contribute to those health outcome patterns as well as better treatments and interventions to enhance child health.

Who was involved?

Researchers looked at health outcomes in 1,092 children across six U.S. cities. Researchers were able to collect measurements of phthalate exposure during pregnancy from 856 of these children’s mothers.

What happened during the study?

The researchers measured 15 health outcomes in children between the ages of 4 and 9 years—including body mass index (BMI), IQ, anxiety, depression, irritability, learning disabilities, speech problems, asthma, wheeze, and nasal allergies. The researchers evaluated how children developed multiple outcomes and investigated how the probability of being in a particular group was affected by exposure to 15 plastic-associated phthalate chemicals during pregnancy. The researchers measured phthalate exposure during pregnancy using urine samples collected from 2007–2014 from mothers during late pregnancy.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

This study’s multi-outcome approach can be used in future studies to identify public health risks that may affect central biological processes that result in multiple negative health outcomes. ECHO Cohort researchers are working to extend this method to include several additional U.S. research sites, which will allow them to evaluate whether similar patterns are observed in a larger dataset. Larger studies will also help researchers characterize how demographic differences like income and sex may influence the development of multiple health outcomes during childhood.

Where can I learn more?

Find the full research article, titled “Subpopulations of children with multiple chronic health outcomes in relation to chemical exposures in the ECHO-PATHWAYS consortium,” in the journal Environment International.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published March, 2024

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Study Finds Link Between Phthalate Exposure During Pregnancy and Development of Multiple Health Outcomes in Children

ECHO Study Evaluates Influence of Neighborhood-Level Poverty and Food Insecurity During Pregnancy on Birthweight

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ECHO Study Evaluates Influence of Neighborhood-Level Poverty and Food Insecurity During Pregnancy on Birthweight

Authors: Izzuddin Aris, Emily Oken, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Previous studies have shown that diet during pregnancy can impact the physical and mental health of the pregnant women. However, less is known about how food insecurity affects health outcomes for newborns. For this study, ECHO researchers analyzed data to understand what connections might exist between where a pregnant woman lives, their access to food, and birth outcomes.

What were the study results?

The study found that living in neighborhoods where residents have lower incomes, limited food access, or limited vehicle access was associated with lower birthweights and an increased risk of babies born small for gestational age. However, researchers didn’t find any association between individual experiences of food insecurity and birth outcomes.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was this study's impact?

Given the long-term effects of adverse birth outcomes on later cardiovascular disease risk and other conditions, more research is needed to evaluate whether interventions and policies that improve food access during pregnancy would be effective in improving birth outcomes and promoting child health. A variety of strategies could be effective at improving birth outcomes, including strategies to increase neighborhood food access, improve food affordability in neighborhoods with low food access, or directly provide healthy foods to individuals during pregnancy.

Who was involved?

This study included 22,206 pregnant participants enrolled in 53 ECHO research sites that collected information on neighborhood-level food access data and birth outcomes. Of these participants, 24% lived in a low-income neighborhood where a third or more residents lived over one mile from a grocery store (or more than 10 miles in rural areas). About 14% of the participants in this study lived in neighborhoods with high poverty rates where more than 100 households had no access to a vehicle and lived more than half a mile from the nearest grocery store.

What happened during the study?

To conduct this study, researchers matched pregnant individuals' home addresses with information about nearby food availability from the U.S. Food Access Research Atlas, which provided data on household income, the availability of a household vehicle, and where people can access food in different neighborhoods. Researchers also assessed individual-level food insecurity during pregnancy using the Crisis in Family Systems-Revised questionnaire.

What happens next?

Additional studies are needed to examine how health habits, chemical exposures, and other related factors may also influence birth outcomes.

Where can I learn more?

Access the full journal article, titled “Birth Outcomes in Relation to Neighborhood Food Access and Individual Food Insecurity During Pregnancy in the Environmental influences on Child Health Outcomes (ECHO)-Wide Cohort Study,” in American Journal of Clinical Nutrition.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published March 1, 2024

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ECHO Study Evaluates Influence of Neighborhood-Level Poverty and Food Insecurity During Pregnancy on Birthweight

ECHO Research Suggests Airborne Lead Exposure Affects Children’s Cognitive Development, Impacting Males More Than Females

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ECHO Research Suggests Airborne Lead Exposure Affects Children’s Cognitive Development, Impacting Males More Than Females

Authors: Amii Kress, Lisa Gatzke-Kopp, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Chemicals used in manufacturing, such as lead, are often released into the air and water. The government sets limits on the amount of pollution that is allowed based on what scientists believe are safe levels for humans. Studies suggest that there is no safe level of lead exposure for children. Despite a substantial decrease in children’s blood lead levels in recent decades, significant disparities in lead exposure still exist. Houses with old lead paint and areas with older and poorly kept housing or corroded pipes pose a higher risk of lead exposure. However, there is limited research on how airborne lead from industrial emissions affects children. This study tested whether lead pollution in the air, even at very low levels, is related to children’s intelligence and executive functioning.

What were the study results?

Children who lived in areas with relatively more lead pollution in the air in the early years of their lives exhibited less impulse control and had slightly lower IQ scores when they reached preschool and school age. Each increase in the level of airborne lead exposure was linked to an average decrease of 0.74 points in children’s IQ scores. The association between lead exposure and executive function was less straightforward in this study, with the influence changing noticeably only at higher levels. This was especially true for boys, who were more sensitive to the effects of airborne lead. Cognitive flexibility, or the ability to adapt to changing situations, and memory did not appear to be affected.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should always consult with a qualified healthcare provider for diagnosis and for answers to your personal questions.

What was this study's impact?

These results suggest that the amount of lead in the air during early childhood may affect children’s brain development. These findings could contribute to a broader approach to children’s health by considering all of the ways that a child’s environment could pose invisible risks. This study suggests that, in addition to efforts to reduce environmental pollution in general, attention to factors like nutrition that may mitigate the impact of exposure on children’s development could reduce health disparities of lead exposure for vulnerable individuals.

Who was involved?

This study looked at over 3,000 children from across the United States who were part of a research study that contributed to the ECHO Cohort.

What happened during the study?

Researchers used children’s home addresses to create a timeline of all the places that they lived from the time they were born until they were 5 years old. They then matched those locations to a database provided by the Environmental Protection Agency (EPA) that estimates the relative amount of lead pollution in the air for every half-square mile yearly. Researchers determined the average amount of exposure over the course of five years for each individual child and then examined whether the level of exposure was related to how the children performed on cognitive and IQ tests when they were between 3 and 8 years old.

What happens next?

Future studies are needed to examine whether other factors in the child’s environment make the effects of lead pollution better or worse. For instance, children with a healthy diet may be less likely to suffer from the effects of air pollution. Furthermore, previous work has suggested that males are more vulnerable to the effects of adverse conditions during neurodevelopment generally. These findings, along with evidence that lead exposure may affect male and female children differently, warrant additional research.

Where can I learn more?

Learn more about the additional data supporting this study through the EPA’s Toxic Release Inventory program. The program offers a Toxics Tracker website that people can use to learn more about the sources of air pollution in their communities.

Access the full journal article titled “Airborne Lead Exposure and Childhood Cognition: The Environmental Influence on Child Health Outcomes (ECHO) Cohort (2003-2022)” in the American Journal of Public Health.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published March, 2024

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ECHO Research Suggests Airborne Lead Exposure Affects Children’s Cognitive Development, Impacting Males More Than Females

ECHO Study Shows Fish Consumption and Omega-3 Supplement Use Uncommon During Pregnancy

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ECHO Study Shows Fish Consumption and Omega-3 Supplement Use Uncommon During Pregnancy

Authors: Emily Oken, Kristen Lyall, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Omega-3 fatty acids are essential nutrients for supporting positive health outcomes. Getting enough of these nutrients during pregnancy is vital for child health and neurodevelopment and may also improve other pregnancy outcomes. Prior research on the demographic characteristics associated with fish and supplement use during pregnancy has been limited, involving fewer participants and older data that may not represent current intake.

What were the study results?

During the study, about 25% of pregnant participants did not eat any fish or ate it less than once per month. Older participants were more likely to eat fish. Participants who were non-Hispanic Black, non-Hispanic Asian, or Hispanic ate less fish on average when compared to those who identified as non-Hispanic White. Participants categorized as overweight were also less likely to eat fish. Only about 1 in 6 pregnant participants reported taking omega-3 supplements. Supplement use was more common in participants who were older and had more education, had a lower body mass index (BMI), and ate fish.

What was the study's impact?

One-quarter of participants in this large, nationwide study rarely or never consumed fish during pregnancy, and omega-3 supplement use was uncommon, even among those who did not consume fish. Given the role of omega-3 fatty acids in preventing preterm birth and supporting child health and neurodevelopment, experts recommend pregnant women get at least 500 mg of omega-3 fatty acids per day through supplements or consuming fish that is low in mercury.

Learn more about the FDA’s and EPA’s current recommendations for eating fish during pregnancy here.

Who was involved?

This study included 10,800 pregnant participants enrolled in 23 ECHO research sites that collected information on fish consumption and 12,646 participants at 35 ECHO research sites that collected information on omega-3 supplement use. Information on fish consumption and omega-3 supplement use was collected from pregnant participants from 1999 to 2020.

What happened during the study?

The researchers collected information on fish intake during pregnancy and grouped participants based on the frequency of their fish consumption: never or less than once per month, once per month to less than once per week, one to two times per week, or more than twice per week. The researchers also collected information on participants’ omega-3 supplement intake. They then compared participant fish consumption and supplement use information across various demographic and lifestyle characteristics, including age, race, ethnicity, education, weight, and smoking status.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your diet without first consulting your healthcare professional.

What happens next?

Future research may examine how fish consumption during pregnancy relates to childhood developmental outcomes such as autism-related traits.

Where can I learn more?

Access the full journal article titled “Demographic and health characteristics associated with fish and n-3 fatty acid supplement intake during pregnancy: results from pregnancy cohorts in the ECHO program” in Public Health Nutrition.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published February 27, 2024

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ECHO Study Shows Fish Consumption and Omega-3 Supplement Use Uncommon During Pregnancy

ECHO Researchers Study the Relationship Between Maternal Education and Children’s Neurocognitive Development Over Time

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ECHO Researchers Study the Relationship Between Maternal Education and Children’s Neurocognitive Development Over Time

Author: Santiago Morales

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Previous research has found a relationship between maternal education and children’s neurocognitive functions, but many of these studies have focused on early childhood. In addition, many previous studies have treated maternal education as something that doesn’t change over time. Few studies have explored whether a mother’s education level over the course of their child’s development might associate with neurocognitive function. ECHO researchers wanted to examine the relationship between changes in a mother’s education over time and their children’s later neurocognitive functioning, such as executive function and language skills.

What were the study results?

A mother’s education level during pregnancy and infancy was associated with children’s language and executive function. Increases in maternal education were related to improved language performance but were not associated with executive functioning performance.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was the study's impact?

The study suggests that early maternal education is strongly associated with later child neurocognitive outcomes. In the study, changes in maternal education were also associated with some of these outcomes. These results suggest that further examining these associations can provide important insights that can help inform policies and interventions designed to foster neurocognitive development.

Who was involved?

The study included 2,688 children, adolescents, and young adults from 3 to 20 years of age at ECHO research sites in 42 states across the U.S.

What happened during the study?

Mothers reported their own education levels during pregnancy and their child’s infancy, and again, years later when their children’s neurocognitive functions were also assessed. For both periods, the study categorized the mother’s education level into one of five groups—less than high school; high school or GED equivalent degree; some college, associate degree or trade school; bachelor’s degree; and graduate degree. The same categories were used to measure maternal education during childhood. Maternal education and income are two commonly used indicators of socioeconomic status. However, missing income data in this study prevented investigators from fully assessing the impact of socioeconomic status and income on neurocognitive skills.

Researchers also measured child participants' cognitive abilities during childhood, adolescence, or young adulthood using the NIH Toolbox Cognition Battery. These tests assess aspects of cognition including language, memory, and problem solving. Test results created scores that reflected language skills, executive function, and overall brain function. The analysis included child participants who contributed at least one score.

What happens next?

While this study suggests an association between maternal education and a child’s neurocognitive function, this research doesn’t necessarily explain the factors or mechanisms involved in that association. Future studies might further explore these factors to provide additional insights.

Where can I learn more?

Access the full journal article, “Maternal Education Prospectively Predicts Child Neurocognitive Function: An ECHO Study,” in Developmental Psychology.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published February 26, 2024

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ECHO Researchers Study the Relationship Between Maternal Education and Children’s Neurocognitive Development Over Time

ECHO Study Finds Link Between Phthalate Exposure and Preterm Birth, Estimates Potential Costs

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ECHO Study Finds Link Between Phthalate Exposure and Preterm Birth, Estimates Potential Costs

Authors: Leonardo Trasande, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of The Director, National Institutes of Health supported this research.

Why was this study needed?

Phthalates are widely used chemicals found in some consumer products, and previous research has linked phthalate exposure to preterm birth. In response, the use of di-2-ethylhexyl phthalate (DEHP), a common type of phthalate, has decreased in recent years. However, there is limited research on the effects of the replacement phthalates, and the costs associated with phthalate exposure remain unquantified. ECHO Cohort researchers wanted to learn about the potential connections between phthalates, their metabolites in the urine of pregnant individuals, and birth outcomes—including birth weight and length of pregnancy. The study also sought to estimate the potential costs associated with adverse birth outcomes.

What were the study results?

When the researchers grouped mothers based on the amount of DEHP metabolites (substances produced when the body breaks down DEHP) found in their urine, they found that the 10 percent with the highest levels had a 50 percent higher chance of giving birth before the 37th week of pregnancy compared to the 10 percent with the lowest levels.

Some common alternatives to DEHP were associated with even higher risk of preterm birth. Women exposed to the highest amounts of these alternative chemicals—phthalic acid, di-isodecyl phthalate (DIDP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP)—had twice the risk of preterm birth compared to those with little to no exposure to these alternatives.

Researchers estimated that the number of premature births in the U.S. that could be linked to phthalate exposure in 2018 was between 24,000 and 120,000, potentially costing between $1.6 billion and $8.1 billion in medical expenses over the lifetime of the children.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was this study's impact?

This ECHO Cohort research examines the effect of phthalates on birth outcomes such as preterm birth and birth weight. These findings associated adverse birth outcomes with exposure to DEHP and its chemically similar substitutes, which can inform the development of policies, programs, and practices that can help prevent or lessen potentially harmful exposures during pregnancy.

Who was involved?

The study included 5,006 mother-child pairs from 13 ECHO Cohort Study Sites across the U.S. Researchers included individuals with information on up to 20 urinary phthalate metabolites. The pregnant participants were aged 25 to 34 at the time they gave birth.

What happened during the study?

The researchers analyzed levels of 20 phthalate metabolites in urine samples collected at three points during each participant’s pregnancy. They also investigated the differences between specific types of phthalates, comparing DEHP with several newer alternatives developed to replace it. Then, the team looked for associations between these metabolite levels and preterm births. They also calculated the number of premature births that could be linked to phthalate exposure and the possible associated costs over the lifetime of the child.

What happens next?

Future research could look at how exposure to replacement phthalates affects child development after birth. The European Union has prohibited the use of certain phthalates in some consumer products—as have California and a few other U.S. states.

Where can I learn more?

Access the full journal article, titled “Prenatal phthalate exposure and adverse birth outcomes in the USA: a prospective analysis of births and estimates of attributable burden and costs,” in The Lancet Planetary Health.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published February, 2024

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ECHO Study Finds Link Between Phthalate Exposure and Preterm Birth, Estimates Potential Costs

ECHO Study Finds Flame-Retardant Chemicals May Increase Risk Of Preterm Birth and Higher Birth Weight

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ECHO Study Finds Flame-Retardant Chemicals May Increase Risk Of Preterm Birth and Higher Birth Weight

Authors: Deborah Bennett, Jiwon Oh, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

Manufacturers commonly use flame-retardant chemicals known as organophosphate esters (OPEs) in products such as furniture, baby items, electronics, clothes, and building materials to prevent fires and make plastics more flexible. People can come into contact with OPEs in various ways, including swallowing or breathing indoor dust or absorbing it through the skin. Animal studies have revealed that OPEs can harm the growth and development of offspring. However, the connection between OPE exposure during pregnancy and birth outcomes has been unclear. ECHO researchers wanted to learn if there was a link between OPE levels in the urine of pregnant individuals and specific birth outcomes.

What were the study results?

Pregnant individuals exposed to specific classes of OPEs may face an increased risk of preterm birth, especially for baby girls and babies with higher birth weights. Three of these substances—diphenyl phosphate (DPHP), a combination of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP), and bis(1,3-dichloro-2-propyl) phosphate—were associated with shorter pregnancies and higher risks of preterm birth only among female infants. Among male infants, higher concentrations of DPHP were associated with longer pregnancies.

Babies born to mothers with detectable levels of three other OPE markers—bis(1-chloro-2-propyl) phosphate, bis(2-methylphenyl) phosphate, and dipropyl phosphate—tended to have higher birth weights compared to those whose mothers had no detectable levels of these substances.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What was this study's impact?

In the past decade, OPEs have been increasingly used as flame retardants after polybrominated diphenyl ether (PBDE) flame retardants were phased out due to health risks. ECHO research examines the potential impact of these now more widespread OPE chemicals on pregnancy outcomes such as preterm birth and birth weight. The findings can inform policies, programs, and practices to help decrease exposure.

Who was involved?

The study included 6,646 pregnant participants at 16 ECHO Cohort Study Sites across the U.S. and Puerto Rico.

What happened during the study?

Researchers measured a total of nine OPE markers in urine samples collected from 6,646 pregnant participants across 16 ECHO Cohort Study Sites—often during their third or second trimesters. The researchers then assessed birth outcomes, including the length of pregnancy and birth weight, using medical records or parent reports.

What happens next?

OPEs tend to stay in the human body for short periods, usually hours to days. To better understand how these chemicals might affect birth outcomes, researchers can use multiple measurements of urinary OPE biomarkers. This could help identify when the body might be more sensitive to these chemicals. Additionally, learning more about how people are exposed to these chemicals can help identify ways to reduce exposure, especially during pregnancy.

Where can I learn more?

Access the full journal article, titled “Associations of Organophosphate Ester Flame Retardant Exposures during Pregnancy with Gestational Duration and Fetal Growth: The Environmental influences on Child Health Outcomes (ECHO) Program,” in Environmental Health Perspectives.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published January 24, 2024

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ECHO Study Finds Flame-Retardant Chemicals May Increase Risk Of Preterm Birth and Higher Birth Weight

ECHO Study Analyzes Relationship Between Molecules During Pregnancy and Childhood BMI

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ECHO Study Analyzes Relationship Between Molecules During Pregnancy and Childhood BMI

Authors: Rachel Kelly, Nicole Prince, Donghai Liang, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

A child’s body mass index (BMI) can be associated with their future health. Some researchers seek to understand how factors during pregnancy may influence childhood BMI. Increasingly, researchers use molecular data to analyze the relationship between pregnancy and childhood health outcomes. Researchers sometimes combine molecular data from multiple study sites to increase the statistical power of these analyses. This study aimed to evaluate molecular data during pregnancy across multiple study sites while also using these data to test a framework for analyzing molecular data across multiple studies.

What were the study results?

ECHO researchers combined the results from multiple ECHO Cohort Study Sites including mothers and their children to determine whether a relationship existed between small molecules present in the mother’s blood during pregnancy and later childhood BMI. Altogether, 20 molecules showed up in all study sites, and 127 molecules showed up in at least two. The study found that the levels of only six small molecules, primarily related to maternal diet, were associated with BMI across all sites. However, statistical analysis across these study sites did not identify significant associations between these molecules and child BMI.

What was this study's impact?

This study demonstrates some of the challenges that arise when harmonizing molecular data across diverse study sites and highlights important considerations for researchers trying to conduct similar analyses. Ensuring that all of the studies used in an analysis have the same standardized procedures for collecting samples, measuring molecules present in those samples, and collecting related data (e.g., BMI, diet) can improve the reliability and reproducibility of results.

Who was involved?

This study involved mothers and their children from multiple study sites: the Atlanta ECHO Cohort, the New Hampshire Birth Cohort, and the Vitamin D Antenatal Asthma Reduction Trial. The researchers included mothers in the second and third trimesters of pregnancy and measured their children’s BMI at the age of two years.

What happened during the study?

For this study, the authors combined existing results from multiple study sites. Pregnant participants provided blood samples, and researchers used those samples to measure a range of small molecules. These molecules provide information on each participant’s health, environment, and biological/genetic factors that could affect their pregnancy. The researchers continued to follow these participants and their children across pregnancy and early life to assess their ongoing health, height, and weight. Ultimately, in this analysis, the authors used data from these studies to evaluate the relationship between molecules measured during pregnancy and BMI at age two years, aiming to identify relationships that were consistent across all three studies.

Footnote: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

Differences in how molecular data were collected and measured between the sites in this study made it difficult to draw strong conclusions on the relationship between small molecules during pregnancy and childhood BMI. Future analyses could involve larger, more standardized studies that all use the same methods for sample collection and measurement. Many ECHO Cohort Study Sites are now measuring small molecules in both mothers and children with a standardized approach under the ECHO Cohort Data Collection Protocol. ECHO researchers have an opportunity to use these data to power analyses that can explore the relationship between pregnancy health and child health outcomes.

Where can I learn more?

Access the full journal article, titled “Metabolomic Data Presents Challenges for Epidemiological Meta-Analysis: A Case Study of Childhood Body Mass Index from the ECHO Consortium,” in Metabolomics.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published January 24, 2024

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ECHO Study Analyzes Relationship Between Molecules During Pregnancy and Childhood BMI