Trends in Socioeconomic Disparities in Obesity Prevalence among Low-Income Children Aged 2-4 Years in Los Angeles County, 2003-2014.

Background: Obesity prevalence among low-income preschool-aged children in the United States decreased between 2010 and 2014. However, this decreasing trend may be varied across socioeconomic subgroups. This study examined trends in obesity prevalence among low-income children from 2003 to 2014 by child's age and household and neighborhood socioeconomic status (SES).

Methods: This study used administrative data for all children, aged 2-4 years, participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Los Angeles County (LAC) during the years 2003-2014. Obesity was defined as having a BMI ≥95th percentile of CDC's age- and sex-specific growth charts. Household income and household educational attainment were indicators of household SES. Neighborhood median household income was an indicator of neighborhood SES.

Results: Childhood obesity prevalence increased sharply from 15.7% in 2003 to 19.1% in 2005, and remained constant until 2010, when it started decreasing. During most years, the prevalence of obesity was higher among the lowest SES groups. Despite the recent decreasing trend, the 2014 estimates were still generally higher than the 2003 levels except among some low-income children living in less-poor and more-educated households.

Conclusions: The decreasing trend between 2010 and 2014 among WIC-participating children in LAC is encouraging and mirrors national trends among WIC-participating children. However, continued efforts should be made to focus obesity prevention efforts on low-income children, especially those who are the most vulnerable as they have experienced significant gains in obesity since 2003.