Abstract Body: Introduction Receipt of lactose-reduced infant formula made with corn syrup solids (CSSFs), a glucose-based infant formula, is highly prevalent in the US and is associated with higher child obesity risk. This study was conducted to assess whether CSSF receipt during infancy is associated with rapid infant weight gain (RIWG), an established risk factor for child obesity.
Hypothesis We hypothesized that CSSF receipt would be associated with higher RIWG risk compared to receipt of other non-CSSF infant formulas.
Methods Administrative data from Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) participants in Southern California, collected from 2013-2020, were used (n=14,002 infants). RIWG was assessed as a change in CDC growth standard weight-for-age z-score ≥0.67 SD from birth to ages 6 to <24 months. WIC-issued infant formula type was used to assess CSSF exposure (any, none; number of months). Multivariable Poisson (RR, 95% CI) and linear risk (risk difference [RD], 95% CI) regression models assessed associations of CSSF receipt with RIWG. Models included independent terms for household poverty; maternal post-partum weight status, education, race/ethnicity and language preference; child age (linear, quadratic), weight-for-length z-score at birth, sex, age at breastfeeding cessation, months of formula issued by WIC, and CSSF issuance (any, none; number of months), and two-way interactions of child age (linear and quadratic) with issuance of CSSF.
Results Weight-for-age z-scores were on average stable from birth to measurements at ages 6 to <24 months (mean [SD] of change in weight-for-age z-score from birth: -0.06 [0.96]), 17.2% of weights measured at ages 6 to <24 months indicated RIWG, and 23.9% of infants had any CSSF receipt. Any CSSF receipt was associated with 30% (RR [95% CI]: 1.30 [1.20, 1.41], p-value <0.0001) and 15% (1.15 [1.04, 1.28], p-value 0.0006) higher relative RIWG risk at ages 1 and 2 years, respectively. Any CSSF receipt was associated with 3.5% (RD [95% CI]: 3.5% [2.2%, 4.8%], p-value <0.0001) and 7.0% (7.0% [3.9%, 10.2%], p-value <0.0001) higher absolute RIWG risk at 1 and 2 years, respectively. Each additional month of CSSF receipt was associated with 3% (RR [95% CI]: 1.03 [1.02, 1.04], p-value <0.0001) and 2% (1.01 [1.01, 1.03], p-value <0.0001) higher relative RIWG risk at 1 and 2 years, respectively.
Conclusions CSSF receipt is associated with higher RIWG risk among WIC-participating children.