Basic Environmental Supports for Positive Brain and Cognitive Development in the First Year of Life.

IMPORTANCE: Defining basic psychosocial resources to facilitate thriving in the first year of life could tangibly inform policy and enhance child development worldwide.

OBJECTIVE: To determine if key environmental supports measured as a thrive factor (T-factor) in the first year of life positively impact brain, cognitive, and socioemotional outcomes through age 3.

DESIGN, SETTING, AND PARTICIPANTS: This prospective longitudinal cohort study took place at a Midwestern academic medical center from 2017 through 2022. Participants included singleton offspring oversampled for those facing poverty, without birth complications, congenital anomalies, or in utero substance exposures (except cigarettes and marijuana) ascertained prenatally and followed up prospectively for the first 3 years of life. Data were analyzed from March 9, 2023, through January 3, 2024.

EXPOSURES: Varying levels of prenatal social disadvantage advantage and a T-factor composed of environmental stimulation, nutrition, neighborhood safety, positive caregiving, and child sleep.

MAIN OUTCOMES & MEASURES: Gray and white matter brain volumes and cortical folding at ages 2 and 3 years, cognitive and language abilities at age 3 years measured by the Bayley-III, and internalizing and externalizing symptoms at age 2 years measured by the Infant-Toddler Social and Emotional Assessment.

RESULTS: The T-factor was positively associated with child cognitive abilities (β = 0.33; 95% CI, 0.14-0.52), controlling key variables including prenatal social disadvantage (PSD) and maternal cognitive abilities. The T-factor was associated with child language (β = 0.36; 95% CI, 0.24-0.49), but not after covarying for PSD. The association of the T-factor with child cognitive and language abilities was moderated by PSD (β = -0.32; 95% CI, -0.48 to -0.15 and β = -0.36; 95% CI, -0.52 to -0.20, respectively). Increases in the T-factor were positively associated with these outcomes, but only for children at the mean and 1 SD below the mean of PSD. The T-factor was negatively associated with child externalizing and internalizing symptoms over and above PSD and other covariates (β = -0.30; 95% CI, -0.52 to -0.08 and β = -0.32; 95% CI, -0.55 to -0.09, respectively). Increasing T-factor scores were associated with decreases in internalizing symptoms, but only for children with PSD 1 SD above the mean. The T-factor was positively associated with child cortical gray matter above PSD and other covariates (β = 0.29; 95% CI, 0.04-0.54), with no interaction between PSD and T-factor.

CONCLUSIONS AND RELEVANCE: Findings from this study suggest that key aspects of the psychosocial environment in the first year impact critical developmental outcomes including cognitive, brain, and socioemotional development at age 3 years. This suggests that environmental resources and enhancement in the first year of life may facilitate every infant's ability to thrive, setting the stage for a more positive developmental trajectory.