The Infant Diet Quality Index Predicts Dietary and Adiposity Outcomes in US Children 2 to 4 years old.

BACKGROUND: Healthy nutrition during the first year of life is critical for optimal growth and development. Limited techniques are available to assess diet quality in infancy, and few have been shown to be predictive of dietary and adiposity outcomes in low-income children. OBJECTIVE: The objectives of this study were to construct an Infant Diet Quality Index (IDQI) to assess the diet quality from birth to 12 mo and to determine whether the IDQI exhibits predictive validity by estimating the longitudinal associations of IDQI scores with diet quality and weight status at 2 to 4 y. DESIGN: Data were analyzed from the longitudinal Women, Infants, and Children Infant and Toddler Feeding Practices Study-2 (unweighted, n = 2858; weighted. N = 392,439) using one 24-h dietary recall and survey responses during infancy. The newly constructed IDQI consists of 16 equally-weighted components: 1) breastfeeding duration; 2) exclusive breastfeeding; age of first introduction of: 3) solids, 4) iron-rich cereals, 5) cow milk, 6) sugar-sweetened beverages, 7) salty/sweet snacks, 8) other drinks/liquids, and 9) textured foods; frequency of consuming 10) fruit or 11) vegetables; frequency of consuming different 12) fruit or 13) vegetables; 14) nonrecommended bottle-feeding practices; 15) use of commercial baby foods; and 16) number of meals and snacks. Regression analysis was used to estimate associations between the total IDQI score (range, 0-1) and Healthy Eating Index-2015 (HEI-2015) scores and body mass index z-scores (BMIz) at 2 to 4 y of age, adjusted for covariates (e.g., child age, sex and race/ethnicity; maternal education level, etc.) RESULTS: The total IDQI score was positively associated with HEI-2015 at the age of 2 y (ß = 16.7; 95% CI: 12.6, 20.9; P < 0.001), 3 y (ß = 14.5; 95% CI: 8.1, 21.0; P < 0.001), and 4 y (ß = 15.4; 95% CI: 8.4, 22.4; P < 0.001); and negatively associated with BMIz at the age of 2 y (ß = -1.24; 95% CI: -2.01, -0.47; P = 0.002) and 4 y (ß = -0.92; 95% CI: -1.53, -0.30; P = 0.003). CONCLUSIONS: The IDQI has predictive validity for diet quality and weight status in low-income US children.