U.S. Nutrition Assistance Program Participation and Childhood Obesity: The Early Childhood Longitudinal Study 2011

The Supplemental Nutrition Assistance Program; Free/Reduced Priced Lunch Program; and Special Supplemental Nutrition Program for Women, Infants, and Children reduce food insecurity for millions of Americans with lower incomes. However, critics have questioned whether they increase obesity. This study examined whether program participation was associated with BMI z-score from kindergarten to fifth grade.

Data from 4,457 primary-grade students whose household incomes were equal to or below 200% of the federal poverty level from kindergarten to fifth grade as part of the Early Childhood Longitudinal Study, Kindergarten Class of 2010‒2011 were analyzed. Marginal structural models with inverse probability of treatment/censoring weights were used to estimate associations between Supplemental Nutrition Assistance Program/Free and Reduced Priced Lunch participation over time and fifth-grade BMI z-score, accounting for lost-to-follow-up and time-varying confounders. Weighted generalized estimating equations were used to examine associations between Special Supplemental Nutrition Program for Women, Infants, and Children participation and BMI z-score trends. All analyses incorporated sampling weights. The Early Childhood Longitudinal Study, Kindergarten Class of 2010‒2011 data were collected from 2010-2016; analyses were conducted in 2021 and 2022.

At baseline, 2,419 (54.3%) respondents participated in the Supplemental Nutrition Assistance Program, 3,993 (89.6%) participated in Free/Reduced Priced Lunch, and 3,755 (84.2%) reported past participation in the Special Supplemental Nutrition Program for Women, Infants, and Children. No associations were found between any program and fifth-grade BMI z-score or between Special Supplemental Nutrition Program for Women, Infants, and Children participation and BMI z-score trend.

Previous findings of relationships between program participation and BMI may have been because of weaker study designs and uncontrolled confounding. Participation in the Supplemental Nutrition Assistance Program; Free/Reduced Priced Lunch; and Special Supplemental Nutrition Program for Women, Infants, and Children was not associated with increased risk of childhood obesity in this recently conducted longitudinal study.