Lactose-reduced infant formula with corn syrup solids and obesity risk among participants in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC)

Abstract

Background: The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), a federal nutrition assistance program supporting low-income families, serves half of United States-born infants, most of whom are issued infant formula by age 2 mo. Obesity prevalence is high among children of low-income households, particularly formula-fed children.

Objectives: This study was conducted to determine whether glucose-based lactose-reduced infant formula made with corn syrup solids (CSSF) is associated with increased obesity risk compared with non-CSSFs that are lactose based.

Design: WIC administrative data on infant formula issuance and child weights and lengths were collected prospectively in Southern California between 2012 and 2020. Included children stopped breastfeeding by 3 mo, were issued cow's milk-based formula through 12 mo, and were enrolled through the final year of WIC eligibility at age 4 y ( n = 15,246). CSSF issuance was assessed continuously (range 0-13 mo) and dichotomously (any, none). Poisson and linear risk regression with robust SE estimates generated risk ratios (RRs), risk differences, and CIs for child obesity [BMI for age (in kg/m 2) ≥95th percentile].

Results: Any CSSF was issued to 23% of children, and 25% were obese at age 4 y. Children with any CSSF issuance had 10% higher obesity risk (RR: 1.10; 95% CI: 1.02, 1.20) than children with no CSSF issuance at age 2 y. Associations remained significant through age 4 y (RR: 1.07; 95% CI: 1.01,1.14), independent of maternal weight status, total formula issued and breastfeeding duration, and were not modified by child race or sex. Obesity risk increased with additional mo of CSSF exposure, reaching 16% higher risk (RR: 1.16; 95% CI: 1.05, 1.28) at age 2 y for children with 12 mo of CSSF.

Conclusions: CSSF issuance is associated with increased obesity risk in the first 5 y life in a dose dependent manner, independently of maternal weight status, breastfeeding duration, and total formula issuance.

Keywords: WIC; child obesity; corn syrup solids; glucose; infant formula; lactose.

FIGURE 1

Mean WLZ trajectories by CSSF and sex among WIC-participating infants of born September 2012 to March 2016 in Southern California (n = 15,246). Mean WLZ and 95% CIs were obtained from a piecewise linear spline mixed effects regression model that included random intercepts, random slopes in each age interval (0.0–0.5, 0.5–1.0, 1.0–1.5, 1.5–2.0, 2.0–3.0, 3.0–4.0, 4.0–5.0 y), and terms for household poverty; maternal postpartum weight status, educational attainment; infant sex, race/ethnicity, age (in months) at last reported breastfeeding, total months of any formula issued by WIC, any CSSF issued by WIC, age at weight/length measurement (and age spline variables), 2-way interaction between any CSSF and child sex, 2-way interactions between any CSSF issued and age (and age spline variables), 2-way interactions between child-sex and age (and age spline variables), and 3-way interactions between child sex, any CSSF issuance, and age (and age spline variables). Mixed models accommodated repeated observations clustered within each child. Groups included the following number of children: male, any CSSF, n = 1886; female, any CSSF, n = 1662; male, no CSSF, n = 5903; female, no CSSF, n = 5795. CSSF, lactose-reduced infant formula made with corn syrup solids; WIC, the Special Supplemental Nutrition Program for Women, Infants, and Children; WLZ, weight-for-length z-score.

FIGURE 2

RRs for child obesity among WIC-participating children in Southern California by number of months CSSFs were issued by WIC (n = 15,246). RRs and 95% CIs were obtained from modified Poisson regression generalized estimating equation models with robust SE estimation that included terms for household poverty, maternal postpartum weight status, educational attainment; infant sex, race/ethnicity, baseline weight-for-length z-score, age (in months) at last reported breastfeeding, total months of any formula issued by WIC, months of CSSF issued by WIC, age at weight/length measurement (linear and quadratic), and 2-way interactions between months of CSSF issued and age (linear and quadratic). Regression models accommodated repeated observations clustered within each child. CSSF, lactose-reduced infant formula made with corn syrup solids; WIC, the Special Supplemental Nutrition Program for Women, Infants, and Children.