NEW RESEARCH: Pregnant women deficient in vitamin D may give birth to obese children

Vitamin D supplements during pregnancy might help curb childhood obesity

by Zen Vuong

Vitamin D deficiency in pregnant women could pre-program babies to grow into obese children and adults, according to a Keck School of Medicine of USC-led study.

Researchers found that 6-year-olds born to mothers with very low vitamin D levels during their first trimester had bigger waists — about half an inch plumper on average — than peers whose mothers had enough vitamin D in early pregnancy. These kids also had 2 percent more body fat.

The prevalence of pregnant women with vitamin D deficiencies has increased in the last 20 years, researchers say. (Photo/iStock)

“These increases may not seem like much, but we’re not talking about older adults who have about 30 percent body fat,” said Vaia Lida Chatzi, senior author of the study and an associate professor of preventive medicine at the Keck School of Medicine. “Even a half-inch increase in waist circumference is a big deal, especially if you project this fat surplus across their life span.”

The study, published in the journal Pediatric Obesity in January, examined the data of 532 mother-child pairs in Greece. Maternal vitamin D concentrations were measured during the first prenatal visit. The child’s health and weight were measured at 4 and 6 years.

The ‘sunshine vitamin’
Some 75 percent of U.S. teenagers and adults have too little vitamin D in their system, according to a 2009 study. Deficiency in this “sunshine vitamin” has been linked to increased risk of heart disease, cancer, multiple sclerosis and Type 1 diabetes.

A newborn’s vitamin D status mostly depends on mom. So infants are at risk of vitamin D deficiency if their mothers are vitamin D deficient or are close to it.

About 95 percent of the vitamin D produced in your body comes from sunshine, Chatzi said. The remaining 5 percent is derived from eggs, fatty fish, fish liver oil and fortified foods such as milk, cheese, yogurt and cereal.

“We’re not sure why there is vitamin D deficiency even in places with abundant sunshine, but maybe people are spending too much time indoors with their screens or typing away in their office cubicles,” Chatzi said. “Or maybe they’re using excessive amounts of sunscreen, which inhibits vitamin D production.”

Pregnant women lack sufficient vitamin D
The prevalence of vitamin D deficiency among pregnant women has increased in the last two decades, Chatzi said. About 66 percent of the pregnant women in the study had insufficient vitamin D in the first trimester, a critical period for organ development.

Previous studies by others provide hints to why low vitamin D levels is a problem. Animal studies have shown that vitamin D suppresses pre-fat cells (adipocytes) from maturing into fat cells. Test tube studies of human fat cells also showed that vitamin D may hinder pre-fat cells from turning into fat cells.

“It’s possible that children of mothers with low vitamin D have higher body mass index and body fat because vitamin D appears to disrupt the formation of fat cells,” Chatzi said. “Optimal vitamin D levels in pregnancy could protect against childhood obesity, but more research is needed to confirm our findings. Vitamin D supplements in early pregnancy is an easy fix to protect future generations.”

Advice to moms: Take prenatal vitamins
None of the Greek women in the study took prenatal vitamin D supplements. Most American doctors recommend that women start taking prenatal vitamins before trying to conceive to make sure folic acid, iron, calcium and other nutritional levels are adequate to prevent birth defects. Most prenatal vitamins contain 400 international units (IU) (10 micrograms) of vitamin D per tablet.

The federal government has not set a recommended daily intake of vitamin D, though many agree the dietary intake of the vitamin should increase with age.

The Institute of Medicine of The National Academies recommends that females 1 to 70 years old consume 600 IU (15 micrograms) of vitamin D daily, regardless of their pregnancy status. The group sets tolerable maximum levels at 4,000 IU (100 micrograms) for pregnant and non-pregnant women who are 19 and older. Lower levels are advised based on age.

Too much vitamin D can cause damage to the heart, blood vessels and kidneys, according to the National Institutes of Health.

“It’s too early for researchers to recommend increasing the standard amount of vitamin D contained in prenatal vitamins,” Chatzi said. “First we need to conduct randomized clinical trials.”

Vasiliki Daraki from the University of Crete was the first author of the study. Theano Roumeliotaki, Georgia Chalkiadaki, Marianna Katrinaki, Marianna Karachaliou, Vasiliki Leventakou, Marina Vafeiadi, Katerina Sarri and Stathis Papavasiliou from the University of Crete; Maria Vassilaki from Mayo Clinic; and Manolis Kogevinas from the Barcelona Institute of Global Health also contributed to the study. Data was obtained from the Rhea project, which was supported by European funds and the Greek Ministry of Health.

In the news and upcoming events: Spring 2018

The California Chapter of the American Lung Association is hosting:
Health Professionals for Clean Air Phone Call
Friday, March 9 | 12:00 to 1:30 PM
They will provide an update on the Low Carbon Fuel Standard, freight issues, SB 375 and the Clean Power Plan. Please RSVP to to receive call-in information.

March for Science: Los Angeles, April 14, 2018
More info at the website and Facebook page

National Air Quality Awareness Week: April 30 – May 4, 2018
More info here. Look for our social media channels to be sharing resources during that week.

Covered through our social media channels recently, we want to share the following stories and articles with you.

Our faculty members Shohreh Farazan and Jill Johnston are partnering with community based organization Comite Civico de Valle, in  Brawley, CA near the Salton Sea to look at children’s respiratory health and how it might be affected by the particle pollution near the shrinking Salton Sea. Read about some of their findings in this article from the Desert Sun. See our infographic that shows the environmental impacts that the shrinking sea has on surrounding communities.

USC staff Lisa Valencia and  CCV staff Beto Martinez work to set up a regulatory air quality monitor in Brawley, CA.

The Los Angeles Times has been covering the health impacts of air pollution. Recent stories that include quotes from our faculty members include:

Regulators warned against housing near freeways due to health risks. Now they’re warming to it (12/27/2017)

Freeway pollution travels farther than we thought. Here’s how to protect yourself (12/30/2017)


California officials say housing next to freeways is a health risk — but they fund it anyway (12/17/2017)

NEW RESEARCH: Teen Exposure to air pollution affects IQ

Southern California Environmental Health Sciences Center researchers JC Chen, Diana Younan, Meredith Franklin, and colleagues recently published work documenting their findings about how air pollution can affect the IQ of teens.

The study can be found here.

Wang, P., Tuvblad, C., & Younan, D., Franklin, M., Lurmann, F., Wu, J., Baker, L., Chen, J.C. (2017). Socioeconomic disparities and sexual dimorphism in neurotoxic effects of ambient fine particles on youth IQ: A longitudinal analysis. PLOS ONE. 12. e0188731. 10.1371/journal.pone.0188731.

Teen Exposure to Air Pollution Could Reduce IQ Levels Long Term

NEW RESEARCH: Increased air pollution linked to aggressive behavior in teens

Tiny, toxic particles creep into developing brains, cause inflammation and may damage brain pathways responsible for emotion and decisions, USC researcher finds.

Related coverage in news media:  U.S. News & World ReportNew York Daily NewsDaily Mail (UK), The Times (UK), The Telegraph (UK)Science News, USC News, Popular Science, Consumer Health Day, International Business Times UK

by Zen Vuong, USC

A new study linking higher levels of air pollution to increased teenage delinquency is a reminder of the importance of clean air and the need for more foliage in urban spaces, a Keck School of Medicine of USC researcher said.

Photo: iStock

Tiny pollution particles called particulate matter 2.5 (PM2.5) — 30 times smaller than a strand of hair — are extremely harmful to your health, according to Diana Younan, lead author of the study.

“These tiny, toxic particles creep into your body, affecting your lungs and your heart,” said Younan, a preventive medicine research associate at the Keck School of Medicine. “Studies are beginning to show exposure to various air pollutants also causes inflammation in the brain. PM2.5 is particularly harmful to developing brains because it can damage brain structure and neural networks and, as our study suggests, influence adolescent behaviors.”

The study, published on Dec. 13 in the Journal of Abnormal Psychology, suggests that ambient air pollution may increase delinquent behavior among 9- to 18-year-olds in urban neighborhoods in Greater Los Angeles. The insidious effects are compounded by poor parent-child relationships and parental mental and social distress, researchers said.

“Previous studies by others have shown that early exposure to lead disrupts brain development and increases aggressive behavior and juvenile delinquency,” Younan said. “It’s possible that growing up in places with unhealthy levels of small particles outdoors may have similar negative behavioral outcomes, though more research is needed to confirm this. Both lead and PM2.5 are environmental factors that we can clean up through a concerted intervention effort and policy change.”

More than just a lung and heart concern

The study followed 682 children in Greater Los Angeles for nine years starting when they were 9. Parents completed a child-behavior checklist every few years and noted if their child had engaged in 13 rule-breaking behaviors, including lying and cheating, truancy, stealing, vandalism, arson, or substance abuse. Up to four assessments were recorded per participant.

Researchers used 25 air quality monitors to measure daily air pollution in Southern California from 2000 to 2014. They computed each participant’s residential address and used mathematical modeling to estimate the ambient PM2.5 levels outside each home. About 75 percent of the participants breathed ambient air pollution that exceeded the federal recommended levels of 12 micrograms per cubic meter. Some areas had nearly double the recommended amount of these particles.

“It is widely recognized that ambient air pollution is detrimental to the respiratory and cardiovascular health of young and old alike. But in recent years, scientists have come to acknowledge the negative impact of air pollution on human brains and behaviors,” said Jiu-Chiuan Chen, an associate professor of preventive medicine at the Keck School of Medicine and senior author of the study.

Environmental scientists and economists have speculated that elevated air pollution levels could increase criminal activities in communities. Interestingly, data show that both ambient PM2.5 concentration and crime rates in Southern California have been on the decline, the study stated. Future studies need to examine whether that is mere coincidence or if tightened air regulations might have contributed to the declining crime rates in many metropolitan areas, the researchers said.

“Poor people, unfortunately, are more likely to live in urban areas in less than ideal neighborhoods,” Younan said. “Many affordable housing developments are built near freeways. Living so close to freeways causes health problems such as asthma and, perhaps, alters teenagers’ brain structures so that they are more likely to engage in delinquent behavior.”

This one-two hit may increase teenage delinquency

The study identified higher air pollution estimates near freeways and in neighborhoods with limited greenspace or foliage.

Researchers noticed more delinquent behavior from boys, African-Americans, adolescents from lower socioeconomic backgrounds and people who lived in downtrodden neighborhoods with limited greenspace when compared to their counterparts.

The bad behaviors associated with increased outdoor air pollution levels were magnified when children did not have good relationships with their parents, lived with depressed mothers or grew up in homes with higher levels of parental stress.

“If you live in an area with high air pollution, like near a freeway or in a neighborhood with little greenery, try to avoid being outside so much and keep windows closed as much as possible when the ambient PM2.5 levels are high,” Younan said. “Try to compensate for air pollution by having a good indoor environment and healthy family dynamics.

“A bad parent-child relationship causes a stressful family environment, and if this goes on for too long, the teenager could be in a chronic state of stress. This could wreak havoc on the body, making teens more vulnerable to the effects of exposure to small particles. Many scientists suspect PM2.5 causes inflammation in the brain or somehow travels directly into the brain and messes with neural network connections, resulting in the observed bad behaviors.”

The data was adjusted for gender, ethnicity, socioeconomic status, neighborhood socioeconomic characteristics and neighborhood quality.

More foliage and cleaner air needed

Younan and her colleagues at the USC Environmental Health Sciences Center have collaborated with researchers and engineers from different disciplines at USC for more than two decades to investigate the insidious effects of air pollution. They found that air pollution increases obesity, that teenagers in urban communities with less foliage (such as parks) tend to be more aggressive and that older women living in areas with PM2.5 levels exceeding the U.S. Environmental Protection Agency’s standard had nearly double the risk for dementia when compared to their counterparts.

Catherine Tuvblad and Laura A. Baker from USC; Meredith Franklin, Lianfa Li and Kiros Berhane from the Keck School of Medicine; Fred Lurmann from Sonoma Technology; and Jun Wu from the University of California, Irvine, contributed to the study.

The research was funded by grant funds from the National Institute of Environmental Health Sciences (R21 ES022369, F31 ES025080). Administrative support was provided by the Southern California Environmental Health Sciences Center. The USC Twin Cohort Study was funded by the National Institute of Mental Health (R01 MH058354).


Professor Ed Avol receives prestigious award recognizing his contributions to air pollution research

At the 2017 annual meeting of the International Society of Exposure Science (ISES), Ed Avol, Professor of Clinical Preventive Medicine at USC, was recognized for his career as an exposure scientist in the field of air pollution research and its public health impacts. Avol received the Constance L. Mehlman Award which aims to “to recognize the ISEA member who has most helped shape a National or State policy with exposure analysis or affected a reduction or prevention of exposure.”

Trained at the California Institute of Technology, Avol’s career as an exposure scientist for over 40 years and his body of work continue to shape state and national policies in terms of providing scientific evidence for reducing air pollution exposures.

His early, groundbreaking work demonstrating respiratory effects of gaseous and particulate air pollutants in carefully controlled clinical exposures with human volunteers transitioned to critical planning and operational roles in the historic southern California Children’s Health Study (CHS) (a longitudinal study of over 12,000 children spanning over 20 years). Avol’s work with colleagues has been frequently cited around the world and has improved our understanding of the impact of air pollution on human health. Numerous publications have resulted from the CHS, documenting and estimating the effects of regional and near-roadway air pollution exposure on children’s lung function growth, school absenteeism, and the prevalence of asthma. He has served on several US EPA Clean Air Science Advisory Committees review panels, contributing to the critical review of scientific evidence (under the Clean Air Act) for setting primary standards for the criteria air pollutants nitrogen oxides, sulfur oxides and particulate matter to protect public health.

In addition to his outstanding contributions to the field of exposure sciences and the impact of his scientific career on policy, Avol’s has made a major commitment to educating and mentoring the next generation of environmental health and exposure scientists at the undergraduate, graduate, postdoctoral and junior faculty level.

“His devotion and generosity in mentoring, and in outreach to communities heavily impacted by environmental exposures, make him a highly respected, admired and cherished colleague and friend. His work ethic and intellect as well as his modesty are truly inspiring,” said Rima Habre, ScD, Assistant Professor of Clinical Preventive Medicine.

About the Constance L. Mehlman Award: Myron Mehlman, the Society’s first President and former managing editor of the Journal of Exposure Analysis and Environmental Epidemiology, endowed a new ISEA award in 1999 in honor of his late wife, Constance Mehlman, an environmental attorney.


New report released documenting research about children’s environmental health

A new report released by the EPA and NIEHS about the impact that environmental exposures have on children’s health. Along with Children’s Center’s from across the country, the research of the Southern California Children’s Environmental Health Center that has been funded by the US EPA and the NIEHS is featured.

“The Children’s Centers examine pressing questions with a wide-angle lens, not allowing the boundaries of any particular field to restrict, define, or determine the array of possible approaches. They bring together experts from many fields, including clinicians, researchers, engineers, social scientists, and others. Relying on a diverse set of disciplines has helped the centers successfully bridge the gap between environmental exposures and health outcomes.” (EPA/NIEHS Children’s Impact Report, Executive Summary).

The report is aims to address the questions and needs of a variety of stakeholders. Image: NIEHS/EPA Children’s Environmental Health and Disease Prevention Centers: Impact Report


As referenced in the report, the Southern California Children’s Environmental Health Center’s research has produced findings related to and including:

  • Maternal exposure to ozone may be associated with reduced birth weight in newborns.
  • Impacts of traffic related air pollution (TRAP) on children’s risk for asthma.
  • Research on the relationship between traffic-related air pollution (TRAP) and Autism Spectrum Disorder suggest that late pregnancy and early life are critical windows of exposure. Measuring residential distance to a major roadway is often used as a marker of TRAP.
  • The interaction between genes and the environmental that may contribute to Autism Spectrum Disorder.
  • Being among the first epidemiological studies to indicate that exposure to air pollution is related to body mass index (BMI) in children.
  • Impact of air pollution on children’s lung function, documenting lung growth when children are exposed to higher levels of pollution and improved lung function when levels have decreased over time.
  • Maternal smoking during pregnancy can affect the respiratory health of her child. Maternal and grandmaternal smoking during pregnancy increased risk of childhood asthma.

In addition, infographics developed by the center were recognized as tools that have helped educate communities about the public health risks of pollution and other toxic exposures.

Read the full report here.

Image: NIEHS/EPA Children's Environmental Health and Disease Prevention Centers: Impact Report
Image: NIEHS/EPA Children’s Environmental Health and Disease Prevention Centers: Impact Report

Environmental Health Research Pilot Project Grants: Up to $50,000 available

The Southern California Environmental Health Sciences Center (SCEHSC, is pleased to announce the 2018 Pilot Projects Program, supporting one-year research projects that aim to promote the understanding of environmental exposures and human disease. The goal of the program is to provide investigators with an opportunity to collect preliminary data and/or validate the utility of specific methods or techniques to establish the feasibility of larger-scale research projects and ultimately seek external (especially NIEHS) funding.

The SCEHSC is seeking investigator-initiated applications from all environmental health research areas.  Topics of special interest include:

  •   New Approaches for Exposure Assessment
  • New Approaches for Environmental Disaster Response Research
  • Climate Change and Environmental Health
  • Environment, Neurodevelopment, and Neurological Diseases
  • Environmental Contributions to Obesity and Metabolic Dysfunction
  • Application of Metabolomics to Environmental Health Research
  • Complex Mixtures in Environmental Health
  • Human Microbiome and the Environment
  • Individuals with a faculty appointment in any department or school/division at USC, CHLA, UCLA, or Caltech are eligible to apply.Request for Applications (RFA)
    Prospective applicants will submit a one-page letter of intent (LOI) and a one-page summary of Specific Aims (SA).  The LOI will include the project title, a brief summary of project objectives and identification of the key participating investigators.  All proposed projects should have a clear and identifiable environmental health emphasis.

    Please e-mail Letters of Intent and Specific Aims by the LOI deadline to Successful LOI applicants will be invited to submit a full proposal.  Instructions for full proposal submission can be found on the SCEHSC website under the Pilot Projects tab:

Deadlines and Notification Schedule
October 2, 2017 at 5 PM: Letter of Intent and Specific Aims Due
October 16, 2017: Invitations to Submit Full Application Sent
November 6, 2017 at 5 PM: Full Applications Due
January 2018: Award Notifications Sent
April 1, 2018: Award Start Date