Long-Run Impacts of an Early-life Nutrition Program: Evidence from the Introduction of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)

To study how access to the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) during the prenatal and early childhood periods affects long-term health outcomes of the affected cohorts.

In order to identify the effects of the WIC program, we exploit variations in the timing of its introduction in different counties and analyze future health indicators of affected cohorts. We use the restricted version of the Panel Study of Income Dynamics, which includes county-level identifiers through the interview year 2019.

Our findings suggest that extending WIC access by one month correlates with a 0.2–0.3% point decrease in asthma incidence (p < 0.1 to p < 0.01) of affected cohorts. Although the connection between WIC and asthma is not fully understood, existing studies suggest potential pathways. Micronutrient deficiencies during early life can impact immune function and inflammation, both relevant to asthma. Moreover, adopting healthier dietary habits may improve microbiome composition, lowering asthma risk. Other indirect benefits of WIC, such as increased use of preventive healthcare services, may also contribute to the prevention of asthma. Despite uncertainties, these estimates remain robust across various model specifications.

Our study implies that early-life nutritional support programs such as WIC may alleviate the burden of asthma, although the specific mechanisms and effect sizes remain unclear. Given the substantial impact of asthma in the U.S., our findings underscore the potential long-term benefits of early-life nutritional support programs for lifelong health.