A tale of two cities: Trends in childhood obesity prevalence in Los Angeles and New York

Objectives. The WIC Program serves over 50% of all infants and 25% of all children under age 5 in the US, and WIC staff measure child height and weight every six months from birth to age 5. Use of existing WIC data systems to compare regional trends in childhood obesity prevalence therefore provides the potential for the surveillance of early childhood obesity among low-income children nationwide. The objective of this study was to conduct a comparative analysis of recent obesity prevalence trends among children enrolled in WIC in Los Angeles County (LAC) and New York City (NYC) in order to begin to explore effective and promising policies and environmental approaches for the prevention and control of early childhood obesity. Methods. We defined obesity as sex-specific BMI-for-age >=95th percentile, and compared prevalence estimates for 3- and 4-year-old children who were enrolled in WIC in LAC and NYC between 2003-2011. Results. In 2003, obesity prevalence among 3- and 4-year old children enrolled in WIC in NYC (18.5% and 19.3%, respectively) was higher than in LAC (16.3% and 17.2%). In 2004, age-specific prevalence estimates in NYC began a 6-year downward trend and corresponding estimates in LAC began a six-year upward trend, with an apparent peak in 2009 and a declining trend in 2010 and 2011. Conclusions. Given the broad reach of the WIC program and high quality of height/weight measurements, these results suggest that WIC data can be an important tool in tracking childhood obesity prior to school age.