A recent study has linked NDVI with childhood obesity.  What’s NDVI?  An exotic virus?  Perhaps a newly discovered DNA sequence?

NDVI is an acronym for “normalized difference vegetation index. “ No, it doesn’t have anything to do with vegging out in front of the TV, though as we have discussed in an earlier blog,  television watching is associated with overweight and obesity.   Rather, it’s a very sophisticated way of estimating the amount of vegetation in an area using satellite images. 

Researchers recently used NDVI to assess the “greenness” of the county that encompasses  Indianapolis, Indiana.¹  They also collected body mass index (BMI) data of children who lived in the county and who were patients in a primary care clinic network.  The BMI data were collected at two time points about two years apart and were transformed for statistical reasons to BMI z-scores.  This is a more sensitive way of assessing change in body composition in growing children.  Additional data used in the analyses included the density of population in the geographic area being studied, racial/ethnic status, gender, and health insurance status as a proxy for socioeconomic status.

The study population was mostly economically disadvantaged African-American children and youth.  In this group and in this location, researchers found that the higher the NDVI score (i.e., the more “green” ) the lower the BMI z-score at the two-year  time point.  Also, the more green the neighborhood environment, the less likely the children's BMI z-scores were to increase over the two-year period.  These results add to the literature that green living spaces are associated with positive health measures in adults and children.

Physical activity is the obvious first thing people might think is the contributing factor in the slowing of overweight and obesity development in this and other similar studies.  And that is likely true.  But there are other factors that may be involved such as a predisposition for families who practice other healthier habits to select greener neighborhoods in which to live.  Or a community spirit among residents located closer to green areas to take better care of their neighborhood thereby deterring crime and hence, making parents more comfortable letting their kids use the green spaces.

Whatever the reasons, “going green” is not just a good slogan for protecting the Earth. It may also be a good mantra for creating neighborhoods that promote healthy weights in our children. 

How “green” is your neighborhood?

¹ Bell JF, Wilson JS, and Liu GC.  Neighborhood greenness and 2-year changes in body mass index of children and youth.  American Journal of Preventive Medicine. 2008;35(6):547-553)