Introduction
We all want our children to thrive where they live, learn, and play. But children are more vulnerable and face a higher risk for health problems from harmful environmental factors, and there are several reasons why.
- Children eat, drink, and breathe more than adults relative to their size.
- Children frequently put objects in their mouths, and play on the floor and ground.
- Protective bodily systems, such as those that filter pollutants from inhaled air and process chemicals in the body, are not yet fully developed.
- During periods of rapid growth and development, normal biological processes may be disrupted by environmental chemicals.
Doctors and scientist do not always know what causes a disease or a disorder. Many factors contribute to development and overall health. Some health conditions are genetic and can be passed from grandparents to parents to children. Some health problems may be caused by injury from things in our environment. Most scientists agree that diseases are probably caused by both, which is called the gene-environment interaction.
Researchers believe that learning more about these interactions offers hope for preventing some health problems. By protecting children, we may also improve their health as adults. Protecting children’s health is a shared responsibility, with parents and guardians supported by their communities, public health professionals, clinicians, and local, state, and federal governments.
What is NIEHS Doing?
Children’s environmental health research is a priority for NIEHS. Using a variety of approaches, NIEHS research and community engagement programs address exposures to chemicals and circumstances during all stages of children’s development.
Childhood Environmental Exposures
Environmental factors can be external to your body, such as pollutants in air, water, and soil or social circumstances, or internal, such as stress.
Air pollution can harm more than lungs, and children are among the most vulnerable to these harms. Emissions from vehicles, manufacturing and power generation, particularly coal-fueled power plants, and fumes from chemical production are primary sources of air pollution. Other sources are wildfires and volcanic eruptions.
The NIEHS-funded, large Children’s Health Study looks at the long-term effects of air pollution on respiratory health. It has linked higher levels of air pollution with increased respiratory infections and measurable lung damage. And, on the other hand, it found that children’s respiratory health improved when air pollution levels declined or the children moved to less polluted areas.
A type of air pollution exposure, particulate matter 2.5, at even relatively low levels, in children aged 9 to 10, may alter the developing brain. This effect could later increase the risk for cognitive and emotional problems in adolescence.
Arsenic, a carcinogen, is a metalloid that occurs naturally in soil and groundwater. Early-life exposure to arsenic is linked to an increased risk of infection, lung and liver disfunction, neurodevelopment and cognitive effects, and skin changes, according to the American Academy of Pediatrics. Arsenic exposure may predispose children to health problems later in life. An increased incidence of lung and bladder cancers was found in adults exposed to arsenic early in life, even up to 40 years after high exposures ceased. These findings provide rare evidence that an early-life environmental exposure can be associated with risk of cancer as an adult.
Fluoride added to drinking water is a public health initiative for improving oral health. The U.S. Public Health Service recommends 0.7 milligrams (mg) of fluoride per liter (L) of water to help prevent tooth decay. But fluoridation of water has also raised concerns. The National Toxicology Program, an interagency program located at NIEHS, found that exposure to fluoride at 1.5 mg/L and higher — twice the recommended level for water — may be linked to lower IQ in children.
Lead in any amount in the body can damage health. Even low lead levels in children’s blood are associated with behavioral problems, delayed puberty, and decreased hearing, cognitive scores, and growth or height. Other NIEHS-funded work found low-level lead exposure was associated with hyperactive/impulsive behaviors but not with inattentiveness.
High blood lead levels in children are due mostly to contaminated paint dust and soil. Other sources include contaminated air and water. Researchers continue to identify when and to what extent children may be exposed to lead. Using baby teeth as a novel way to identify and measure chemical exposure, NIEHS-funded researchers linked higher levels of lead in those teeth to autism in children.
NIH-funded research (including NIEHS) found racial segregation makes consequences of lead exposure worse. The study linked detailed birth records with lead screening and standardized testing data for almost 26,000 children, all born in the year 2000. Among the children with higher blood lead levels, test scores decreased as racial segregation increased. This effect became more marked as blood lead levels increased.
Neighborhood characteristics, particularly high poverty and unemployment, may pose an environmental risk to the developing brains of children, according to NIEHS-funded research. Disadvantaged neighborhoods may also lack quality health services, access to nutritious foods, parks and recreational facilities, and have more pollutants.
Racial segregation may make the consequences of lead exposure worse. A study linked detailed birth records with lead screening, standardized testing, and Census data for almost 26,000 children. Among the children with higher blood lead levels, test scores decreased as racial segregation increased. This effect became more marked as blood lead levels increased.
Prenatal Health Effects
Research shows that prenatal contact with certain environmental factors influences whether some diseases may happen later in life. By learning more about the developmental origins of health and disease, children’s proper growth and quality of life can be improved.
Prenatal nutrition may play a role in reducing the chance that certain conditions develop. NIEHS researchers reported that when pregnant women improved their nutrition and reduced exposure to hazardous chemicals, they were more likely to have healthy babies, and their children were better able to cope with environmental stressors later in life.
Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by difficulty interacting with other people and restrictive or repetitive patterns of behavior. Environmental factors and genetics are thought to contribute to ASD, which affects 1 in 36 children in the U.S., according to the Centers for Disease Control and Prevention.
ASD rates were lower in children whose mothers took a prenatal vitamin with folic acid during early pregnancy. Additionally, when mothers of children with autism spectrum disorder took prenatal vitamins with folic acid beginning in the first month of subsequent pregnancies, the occurrence of autism in those children was reduced by about half.
NIEHS-supported research linked genetics and air pollution exposure during pregnancy to increased risk of ASD. Other NIEHS-funded researchers discovered pregnant mothers exposed to pesticides or experiencing inflammation from ailments such as infections, diabetes, or obesity also have a higher chance of having a child with ASD.
Cancer, particularly leukemia and cancers of the brain and central nervous system, is the second leading cause of death among children under 14, according to the Centers for Disease Control and Prevention. Its incidence may be affected by prenatal nutrition or exposure to chemicals. For example, the children of women who took vitamins, including folic acid, before and during pregnancy had a reduced chance of developing childhood leukemia. Other research showed a greater chance of leukemia developing in children whose mothers were exposed to pesticides during pregnancy, or whose fathers were exposed to pesticides around the time of conception.
Childhood Health Effects
Asthma, a chronic disease in lung airways, is triggered by mold, air pollution, pest allergens, tobacco smoke, and other exposures. Scientists are still researching what may initially cause asthma. In one study, infants living in homes with high levels of mold from water-damaged buildings were more likely to develop asthma by age seven.
Exposure to air pollution has been consistently shown to set off asthma in children. A large 2024 study shows early life air pollution is linked to increased asthma incidence by early and middle childhood, with higher risk among lower-income, urban families.
NIEHS-funded research shows vitamin D appears to have a protective effect for children with asthma. Children with asthma who had low blood levels of vitamin D had worse asthma than children with higher vitamin D levels.
Neurodevelopmental disorders, such as symptoms of attention deficit hyperactivity disorder, problems with fine motor coordination, and lower cognition, were found in children exposed to high levels of flame retardants, polybrominated diphenyl ethers. Flame retardant chemicals are often applied to upholstered furnishings, mattresses, carpets, electronics and electrical devices, and construction materials.
Air pollutants called polycyclic aromatic hydrocarbons (PAH) come from burning fossil fuels and other combustion. Studies have found consistent evidence that lower IQ scores and behavior problems are associated with exposure to PAH.
Puberty in girls is changing. Girls in the U.S. appear to be getting their first menstrual periods earlier, about 6 months sooner on average than decades ago. Early onset puberty is a concern because of links to diabetes, heart issues, breast and endometrial cancers, fertility issues, and mental health, according to the Endocrine Society.
Puberty may be affected by chemicals known as endocrine disruptors. These chemicals can mimic, or interfere with, the body’s hormones and alter the balance needed for proper development and good health. Small hormonal disruptions can cause significant biological effects.
- NIEHS and other researchers are seeing early onset puberty tied to endocrine disruptor exposures. To advance understanding of this connection, certain chemical structures were identified that may cause the body to release puberty-related hormones earlier than it would otherwise.
- During puberty, frequent use of personal care products that contain endocrine disruptors is associated with an increased chance of developing breast cancer later in life. Some of the commonly found endocrine disruptors are chemicals called phthalates, parabens, and phenols.
NIEHS Research Efforts
- NIEHS Children’s Environmental Health Translation Centers – Building on a 20-year base of robust research in children’s environmental health, NIEHS established a network of collaborative centers to translate key research findings into clinical and public health practice. Examples of research translation may include communication strategies, risk management strategies, public health interventions and practices, curriculums and educational activities and toolkits, clinical guidelines, policies, and other products. Such products are intended to help protect and improve children’s environmental health and to promote health equity.
- NIEHS Pediatric and Reproductive Environmental Health Scholars – This program trains pediatricians, obstetricians, gynecologists, and related professionals with a goal of creating a network of healthcare professionals who tackle the complexities of pediatric and reproductive environmental health.
- NIH ECHO – Researchers focus on pre-, peri- and postnatal outcomes; upper and lower airway health; obesity; neurodevelopment; and positive health, such as a sense of wellbeing. NIEHS contributes to ECHO studies.
Further Reading
Stories from the Environmental Factor (NIEHS Newsletter)
- October Is Children's Health Month (October 2024)
- Some Endocrine Disruptors May Contribute to Early Puberty, Study Finds (October 2024)
- New Web Tool Integrates Research on Autism and the Environment (October 2024)
- Data-driven Approaches Fuel Research on Children’s Brain Health (August 2024)
- Fluoride Exposure During Pregnancy May Increase Neurobehavioral Problems in Children (August 2024)
- New Technology Detects Molecular Signatures That Can Predict Autism Risk (May 2024)
- NIEHS-supported Research Can Help People With Asthma Breathe Better (May 2024)
- Brain Scans Yield Insights Into Autism, Other Developmental Disabilities(May 2023)
- Paternal Exposure to Phthalates Could Have Intergenerational Effects on Metabolic Health(April 2023)
- Effects of Flame Retardants, Maternal Diet on Children Focus of Talks (September 2022)
- Links Between Nutrition, Exposures, and Autism Focus of NIEHS Event (July 2022)
- Neighborhood Disadvantage May Affect Brain Development (June 2021)
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Fact Sheets
Podcasts
- Artificial Turf and Your Health (2024) - NIEHS-funded researcher Homero Harari, Sc.D., talks about the potential health and safety concerns of playing on artificial turf. He also discusses how communities can make informed decisions about whether to install synthetic surfaces at schools, parks, and playgrounds.
- Climate Disasters and Mental Health in Youth (2024) - NIEHS-funded researcher Maggie Sugg, Ph.D., talks about how climate disasters may affect mental health in youth. She suggests strategies to promote mental health resilience in young people and communities affected by disasters.
- Incorporating the Environment Into Maternal and Child Health Care (2024) - The NIEHS Pediatric and Reproductive Environmental Health Scholars program is teaching health care professionals about the many interactions that occur between children, pregnant women, new mothers, and their environment.
- Autism and the Environment (2024) – NIEHS-funded researcher Staci Bilbo, Ph.D., professor at Duke University, explains how environmental exposures and stress, especially during early development in the womb, influence children’s brain and behavioral development.
- The Shrinking Salton Sea and Children’s Health (2022) – NIEHS-funded researchers describe their community-based project in Imperial Valley, California, that addresses local concerns about children’s lung health due to potential nearby air pollution. The Salton Sea, a salt lake with a receding shoreline, has lakebed dust that may add harmful particulates to the community’s air.
- Why Neighborhoods Matter: Brain Development in Children (2021) – Megan Herting, Ph.D., discusses why neighborhoods matter when it comes to brain and cognitive development. She also shares her thoughts on how we can promote neighborhood equity to improve children’s health and development.
- Using Culturally Appropriate Messages to Promote Smoke-free Homes (2021) – To decrease tobacco use and secondhand smoke among tribal populations, the culture and traditions of tribal communities must be considered. Patricia Nez Henderson, M.D., shares her experience working with tribal communities to encourage smoke-free homes, with the goal of improving their health.
- Wildfire Smoke and Children's Health (2021) – Stephanie Holm, M.D., discusses children’s health risks from wildfire smoke exposure. She also offers advice to pediatricians and parents on how to keep kids safe during a wildfire event.
Additional Resources
- President's Task Force on Environmental Health Risks and Safety Risks to Children – Working together, federal government agencies seek to understand environmental health effects and help to ensure opportunities for the development of healthy children.
- Kids Environment, Kids Health – A resource for kids, parents, and teachers to find fun and educational materials related to health, science, and the environment we live in today.