The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is the third largest nutrition assistance program in the U.S. Approximately one quarter of American children younger than five were covered by the WIC program. Participants receive not only free packages of nutritious food, but also nutrition education. It is important to examine whether WIC participation is associated with lower obesity risk of participating children.


We used the data from the National Health and Nutrition Examination Survey (NHANES) 1999-2014. The analytical sample included 4,306 children aged 2 to 5 with complete body mass index (BMI) and WIC participation in the last 12 months.The sample was stratified into two groups: WIC participants, and eligible non-participants. Childhood obesity (overweight) was defined as the BMI >= 95th percentile (85th percentile <= BMI < 95th percentile) for children at the same age and sex.The prevalence of childhood overweight and obesity was estimated for each wave in each group to examine the trend. Log binomial regression was applied to examine the relationship between WIC participation and obesity (overweight) risk while controlling subjects' socio-demographics.


In the pooled sample, WIC participating children had a lower obesity prevalence than eligible non-participants (12.1% vs. 12.5%) but higher overweight prevalence (15.2% vs. 12.2%). The risk ratios of WIC participation in overweight and obesity were 1.25 (P=0.15) and 1.08 (P=0.58). However, the WIC participating children had a significant trend in increasing overweight (P=0.043) while the trend in eligible non-participating children was insignificant (P>0.05). No significant trend in obesity was observed in both groups.


WIC participation had no significant relationship with overweight or obesity reduction among eligible low-income children in the U.S. More efforts are needed in the WIC program to reduce childhood overweight or obese among participants.