NEWS RELEASE: Research links tobacco smoke and roadway air pollution with childhood obesity

LOS ANGELES — New research from Keck Medicine of the University of Southern California (USC) bolsters evidence that exposure to tobacco smoke and near-roadway air pollution contribute to the development of obesity.

The study, to be posted online Wednesday, Nov. 12, 2014 in Environmental Health Perspectives, (click here) shows increased weight gain during adolescence in children exposed to secondhand tobacco smoke or near-roadway air pollution, compared to children with no exposure to either of these air pollutants. The study is one of the first to look at the combined effects on body mass index of exposure to both near-roadway air pollution and tobacco smoke. The effects were substantially greater in children exposed to both air pollutant mixtures than to either alone.

“Vehicle miles traveled, exposure to some components of the near-roadway air pollutant mixture, and near roadway residential development have increased across the United States over the last several decades corresponding to the epidemic of childhood obesity,” said Rob McConnell, M.D., professor of preventive medicine, Keck School of Medicine of USC and lead author on the study. “The potential for near-roadway air pollution to be among several factors contributing to the epidemic of obesity merits further investigation.”

The research builds on previous studies showing that exposure to secondhand smoke and particulate air pollution cause heart and lung disease.

Childhood obesity has doubled in children and quadrupled in adolescents in the past 30 years, according to the Centers for Disease Control and Prevention (CDC). Obese youth are more likely to suffer from health challenges, including high cholesterol, high blood pressure, diabetes, bone and joint problems, social stigmatization and self-esteem problems. Obesity for children is defined by the CDC as a BMI at or above the 95th percentile for children of the same age and sex.

The USC study examined exposure of more than 3,000 children to tobacco smoke during their mothers’ pregnancy and to secondhand smoke, as well as air pollution effects from busy roadways, and looked for associations with body mass index. The children were enrolled at age 10 in the Southern California Children’s Health Study, started in 1992 to study the long-term effects of air pollution on children. The children were followed yearly over an eight-year period through high school graduation at age 18. Most of the children were non-Hispanic white or Hispanic.

The researchers estimated near-roadway pollution exposure, taking into account traffic volume, how close the children lived to roadways and predominant wind direction. At study entry, a parent-completed questionnaire was used to determine lifetime tobacco smoke exposure.

“Further research is needed to determine if our findings can be replicated in other populations,” McConnell said, “and to assess both the potential contribution of combustion sources to the epidemic of obesity and the potential impact of interventions to reduce exposure.”

Funding for the research comes from the National Institutes of Health (grants P01ES022845, P30ES007048, P01ES009581, P01ES011627, P50 CA180905, R01ES016535, R01HD061968 and R03ES014046), the Environmental Protection Agency (grants RD83544101, R826708 and RD831861) and the Hastings Foundation.

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McConnell, R., Shen, E., Gilliland, F.D., Jerrett, M., Wolch, J., Chang, C., Lurmann, F., Berhane, K. (2014). A Longitudinal Cohort Study of Body Mass Index and Childhood Exposure to Secondhand Tobacco Smoke and Air Pollution: The Southern California Children’s Health Study. Environmental Health Perspectives. Published online Nov. 12, 2014.

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ABOUT KECK MEDICINE OF USC
Keck Medicine of USC is the University of Southern California's medical enterprise, one of only two university-based medical systems in the Los Angeles area. Encompassing academic, research and clinical excellence, the medical system attracts internationally renowned experts who teach and practice at the Keck School of Medicine of USC, the region’s first medical school.

For more information, go to www.keckmedicine.org/beyond

This news release was prepared by USC Health Sciences Public Relations & Marketing and the Division of Environmental Health.

Hong Kong Air Quality Researcher, Simon Ng Visits USC

Simon Ng, Chief Research Officer at Hong Kong-based nonprofit Civic Exchange, visited the Environmental Health Division on November 3 to present and share information on port air pollution surrounding Hong Kong. Civic Exchange is an “independent public policy think tank undertaking research to advance civic education and engage society to shape public policy.” During Ng’s presentation, researchers at USC Environmental Health and community partners were interested to hear about factors that make Hong Kong both similar and quite different compared to the ports of LA and Long Beach. Being surrounded by water on three sides, Hong Kong is greatly impacted by pollution that is generated from ships traveling to ports on either side of the city, not to mention ships that travel directly to Hong Kong’s port. This makes for some unique challenges in that Ng and colleagues at Civic Exchange must work with a wide variety of local and international stakeholders as they seek to reduce port emissions in and around Hong Kong.

Ng and Civic Exchange have published several reports on the public health impacts of ship emissions in the area, a hot topic for cities with large ports around the world. The reports provide a detailed look at the scope of the problem and control options; valuable information for those looking at policy options and government interventions at ports.

In recent years, Ng and Civic Exchange have partnered with the University of Hong Kong Public Health School on developing a website: The Hedley Environmental Index, which quantifies the financial burden that air pollution places on the region around Hong Kong. This unique site gives the viewer a real-time view of the ever increasing factors and costs such as deaths, hospital bed days, doctor visits and total economic loss. When visiting this site, one can also see real-time concentrations of specific pollutants around Hong Kong.

Civic Exchange is collaborating with the Urban & Environmental Policy Institute at Occidental College on a China – Environment project funded by the LUCE foundation which sponsored Simon’s week long activities in Southern California.