Being exposed to high levels of pollution can adversely affect fetal growth and development, according to a recent study.
Researchers at the University of Rochester found that women who were pregnant during the 2008 Beijing Olympics, when pollution levels were reduced by the Chinese government, gave birth to children with higher birth weights compared to those who were pregnant before and after the games.
"The results of this study demonstrate a clear association between changes in air pollutant concentrations and birth weight," David Q. Rich, lead author of the study and an epidemiologist with the University of Rochester Medical Center (URMC) Departments of Public Health Sciences, said in a statement. "These findings not only illustrate one of the many significant health consequences of pollution, but also demonstrate that this phenomenon can be reversed."
In the months leading up to and during the 2008 Beijing Olympics and Paralympics the Chinese government launched a series of measures to improve the city's chronic and notoriously poor air quality. These measures included closing factories, halting construction projects, seeding clouds to induce rainfall, and implementing strict restrictions on automobile and truck use.
These measures produced a significant decrease in the concentrations of particulate and gaseous air pollution for a six to seven week period during the Olympic games, including a 60 percent reduction in sulfur dioxide, a 48 percent reduction in carbon monoxide, a 43 percent reduction in nitrogen dioxide, and a reduction in particles smaller than 2.5 microns in diameter.
These controls also created a unique "natural experiment," giving scientists the ability to study the impact of pollution on human health. A prior study by this group, which was also conducted in concurrence with the Beijing Olympics, demonstrated that pollutions levels were linked to physiological changes that increase risk for cardiovascular disease, and that these same air pollution reductions resulted in improvements in several risk factors
For the study, researchers compiled information from nearly 84,000 term births to mothers in four urban districts in Beijing. They compared birth weights for mothers whose eighth month of pregnancy occurred during the 2008 Olympics/Paralympics with those whose eighth month of pregnancy occurred at the same time of year in the years before (2007) and after (2009) the games when pollution levels were at their normally higher levels.
They found that the babies born in 2008 were on average 23 grams larger than those in 2007 and 2009. Their findings suggest that pollution may be interfering with this period of development.
The findings are detailed in the journal Environmental Health Perspectives.
