If a tree grows in Brooklyn, the kids on the block might grow healthier. New research reported in the December issue of the  American Journal of Preventive Medicine found that children living in inner city neighborhoods with higher "greenness" experienced lower weight gains compared to those living in areas with less "greenness." The researchers defined "greenness" as areas with vegetative coverage, such as open spaces, yards and parks. They used satellite imaging data to measure the vegetative coverage.

The study, conducted by researchers from University of Washington, Indiana University, Purdue University and Indiana University School of Medicine, is the first to examine the effects of greenness on inner city children over time. Researchers followed more than 3,800 children over two years. The children, predominantly African American and poor, were between the ages of 3 and 16. The study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases.

"This study's findings align with previous research linking exposure to green landscapes with health improvements," says Janice F. Bell, PhD, assistant professor in the department of Health Services at the School of Public Health and Community Medicine, University of Washington, Seattle in the article accompanying the study. "Among adults, greenness is associated with less stress and lower [body mass index], improved self-reported health and shorter post-operative recovery periods. Among children and youth, the positive health effects of green landscapes include improved cognitive functioning and reduced attention deficit hyperactivity disorder symptoms."

In previous studies of adults, residential density tended to predict physical activity levels, with highly urban environments leading to more walking, less driving and lower BMI. The current study did not find this correlation for children.

"Ideally, future research in this area will be multidisciplinary — involving city planners, architects, geographers, psychologists and public health researchers — and will consider the ways children live and play in urban environments," says Bell.