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A Wider Search for Obesity

By Andrew Myers

Over the last two decades, the soaring prevalence of childhood obesity has alarmed and perplexed the public health community. Yet, there has been a precious little understanding of the complex interplay of environmental factors that influence obesity.

Now, a team of Bloomberg School researchers has begun a massive, first-of-its-kind study to explore the community dynamics of childhood obesity. The multi-component study, led by Thomas A. Glass, PhD, MA, and Brian S. Schwartz, MD, MS, who are part of the Johns Hopkins Global Center on Childhood Obesity, will look at numerous community factors that contribute to childhood obesity, including land use and food environments, as well as physical activity settings and social contexts. "This will provide an unprecedented and richly detailed view of childhood obesity," says Glass, an Epidemiology professor.

"This study is about big data and big epidemiology," says Schwartz, a professor of Environmental Health Sciences. "We will have longitudinal data on both risk factors affecting obesity and height and weight measurements throughout childhood, something few if any prior studies have used."

Health data will be drawn from the electronic health records of a large health care provider; the study includes more than 164,000 children in some 1,300 communities in almost 40 counties in central and northeastern Pennsylvania. Longitudinal aspects will evaluate how body mass index trajectories and community contexts such as population density, socioeconomic status and distance to food sources have changed since 2001.

Among its more intriguing aspects, the study will also measure DNA methylation-a biochemical process by which genes are turned on and off in cells-to assess how community environments potentially alter gene expression and influence obesity.

"This will be among the first studies of community factors, childhood obesity and DNA methylation, which is thought to play a role in stress, appetite control and inflammation systems," Schwartz says. "This may tell us how a variety of community factors like neighborhood design, food proximity and walkability literally 'get under the skin' to influence health."

He adds: "We're still early in the study, but we already know how several individual health factors-family socioeconomic status, child diagnoses, child medications and community deprivation-are influencing body mass index growth in early, middle and late childhood."