Infant dietary patterns and early childhood weight outcomes: a secondary analysis from the Starting Early Program Trial

Background: Limited studies assess how infant dietary patterns impact child weight. The Starting Early Program (StEP) promotes healthy nutrition during pregnancy and infancy and leads to healthier child weight, but whether dietary patterns contribute to weight or mediate StEP weight outcomes has not been studied. Objectives: This secondary analysis identified infant dietary patterns in StEP, determined associations between dietary patterns and child weight outcomes, and examined whether dietary patterns mediated the relationship between StEP and child weight. Methods: Data were from 377 mother-infant dyads enrolled in a randomized trial testing the efficacy of StEP. Infant diet was assessed at 10 months using an interviewer-administered 24-hour recall, and dietary patterns were identified using latent class analysis. Child weights were abstracted from medical records at 12, 24, and 36 months. Associations between infant dietary patterns and weight-for-age z-score (WFAz) and likelihood of being classified as overweight (WFA ≥85 ^th percentile) were assessed using multivariable linear and logistic regression models. Mediation analyses were used to assess intervention effects on WFAz via impacts on infant dietary patterns. Results: Four classes of infant dietary patterns were identified, characterized by differences in milk feeding and complementary food type and variety: Breastfed-High variety; Formula fed-High variety; Formula fed-Low variety; and Mixed fed-Low variety. Compared to the Breastfed-High variety class, infants in the Formula fed-Low variety class had higher WFAz and were more likely to be classified as overweight at 24 and 36 months. Participation in StEP increased membership in Breastfed-High variety, which mediated the association between StEP and lower WFAz at 24 months. Conclusions: Infant dietary patterns were identified and associated with child obesity risk. StEP promoted an infant dietary pattern that was most consistent with infant feeding guidelines, which mediated intervention effects on child weight.