Air Pollution in China and Children's Health

Decreased exposure to air pollution in utero is linked with improved childhood developmental scores and higher levels of brain-derived neurotrophic factor (BDNF), a key protein for brain development, according to a study looking at the closure of a coal-burning power plant in China led by researchers at the Columbia Center for Children’s Environmental Health at the Mailman School of Public Health.

The study is the first to assess BDNF and cognitive development with respect to prenatal exposure to polycyclic aromatic hydrocarbons (PAH), a component of air pollution commonly emitted from coal burning. Results appear online in the journal PLOS ONE.

The 2004 closure of a coal-burning power plant in Tongliang, China provided the opportunity to investigate the benefits to development and the impacts on BDNF associated with decreased levels of exposure to PAH. The new study links decreases in air pollution with decreased levels of PAH-DNA adducts in cord blood, a biological marker of exposure, and reported an association between PAH exposure and adverse developmental outcomes in children born before the plant closure. Currently, coal-fired power plants produce more than 70% of China’s electricity.

Deliang Tang, MD, DrPH, and his colleagues followed two groups of mother-child pairs from pregnancy into early childhood. One of the groups was comprised of mothers pregnant while the coal power plant was still open and the other after it closed. Developmental delay was determined using a standardized test, the Gesell Developmental Schedule (GDS), which was adapted for the Chinese population. The GDS assesses children in four areas: motor skills, learned behaviors, language, and social adaptation.

The researchers found that, as hypothesized, decreased PAH exposure resulting from the power plant closure was associated with both increased BDNF levels and increased developmental scores. PAH-DNA adducts were significantly lower in the babies born after the coal power plant shutdown as compared to those born before the closure, indicating a meaningful exposure reduction. Moreover, the researchers found that the mean level of BDNF was higher among children born after the closure of the power plant. The impacts of PAH exposure and BDNF on developmental scores was also analyzed considering all the children, including both the pre- and post-closure groups. Increased scores in the average, motor, and social areas were linked with higher levels of BDNF.

“The key to limiting the health impacts of environmental exposures is policy change supported by scientific evidence. These findings indicate that regulation can rapidly decrease exposure and improve health outcomes among the most sensitive populations, providing support for implementing additional measures such as the closure of the Tongliang coal-fired power plant,” says Dr. Tang, director of the China studies at the Columbia Center for Children’s Environmental Health and associate professor of Environmental Health Sciences at the Mailman School.

Additionally, the results provide important insight into the relationship between PAH exposure, BDNF, and developmental outcomes, and evidence for BDNF as a marker for the neurodevelopment effects of exposure to air pollution. More research is necessary to determine if the damage caused by environmental exposures, such as PAH, can be mitigated by presence of an enriched environment.

Support for the study was provided by the Energy Foundation, the Rockefeller Brothers Fund, and the Schmidt Foundation.

Additional authors include Frederica P. Perera, DrPH, PhD, director of the Columbia Center for Children’s Environmental Health; Joan Lee, MPH; Loren Muirhead, MPH; Lirong Qu, MD; and Jie Yu, MD—also at the Center; and Ting Yu Li, MD, at Chongqing Medical University, Chongqing, China.

About Columbia University’s Mailman School of Public Health

Founded in 1922, Columbia University’s Mailman School of Public Health pursues an agenda of research, education, and service to address the critical and complex public health issues affecting New Yorkers, the nation and the world. The Mailman School is the third largest recipient of NIH grants among schools of public health. Its over 450 multi-disciplinary faculty members work in more than 100 countries around the world, addressing such issues as preventing infectious and chronic diseases, environmental health, maternal and child health, health policy, climate change & health, and public health preparedness. It is a leader in public health education with over 1,300 graduate students from more than 40 nations pursuing a variety of master’s and doctoral degree programs. The Mailman School is also home to numerous world-renowned research centers including ICAP (formerly the International Center for AIDS Care and Treatment Programs) and the Center for Infection and Immunity. For more information, please visit www.mailman.columbia.edu.