Longer Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) Participation Duration Is Associated with Higher Diet Quality at Age 5 Years

Background The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides supplemental healthy foods and nutrition education to children under age 5 y in low-income households. Objectives We aimed to identify characteristics associated with duration of WIC participation and assess how participation duration relates to household food insecurity (HFI), child diet quality, and child weight status at age 60 mo. Methods This analysis of the WIC Infant and Toddler Feeding Practices Study-2, a prospective cohort of WIC-participating children enrolled in 2013, included children with complete baseline-60 mo data (n = 836). Outcomes assessed with WIC participation duration in multivariable regression were HFI (USDA 6-item Household Food Security Screener), child diet quality on a given day [Healthy Eating Index (HEI)-2015], and obesity (CDC BMI-for-age >= 95th percentile). Results Factors associated with longer WIC participation included male sex; lower household income; reported diet changes in response to WIC nutrition education; household Supplemental Nutrition Assistance Program participation; English-speaking Hispanic, Spanish-speaking Hispanic, and non-Hispanic other maternal race-ethnicity and language preference; an ever-married mother; lower maternal education; higher maternal age; earlier enrollment during pregnancy; and reporting a subsequent pregnancy. Longer WIC participation was associated with lower HFI odds (OR: 0.69; 95% CI: 0.51, 0.95), higher total HEI-2015 (beta: 0.73; 95% CI: 0.20, 1.25), and higher obesity odds (OR: 1.20; 95% CI: 1.05, 1.37) in multivariable-adjusted regression models. Conclusions Longer WIC participation was associated with reduced HFI and higher diet quality, and unexpectedly with higher obesity odds, at 60 mo. Further research is needed to confirm and understand mechanisms underlying the unexpected associations identified with longer WIC participation (e.g., male sex, obesity). Groups with shorter participation durations may benefit from targeted WIC retention efforts to maximize nutrition security.