The impact of socio-environmental factors on brain structure over the early life course of preterm-born individuals - A systematic review

Approximately 11% of births worldwide are preterm (<37 weeks). While research traditionally focuses on complications of prematurity and brain development, the role of socio-environmental factors has received less attention. Recent studies indicate these factors significantly influence neurocognitive outcomes and brain development, beyond prematurity alone. This review examines the impact of socio-environmental factors on brain structure and function in preterm-born individuals from birth to early adulthood. We conducted searches in PubMed, Embase, and Web of Science for studies up to August 28th, 2024, examining socio-environmental effects on brain structure or function in preterm-born individuals using magnetic resonance imaging. From 891 articles screened, 23 met the inclusion criteria. Socio-environmental factors, including socioeconomic status, prenatal conditions, hospital environment, and early life experiences, notably affect brain structures in preterm-born individuals. Key impacts were found in limbic and associative cortices (e.g., cingulate gyrus, parieto-temporal cortices), white matter tracts involved in executive functioning (e.g., superior longitudinal fasciculus, cingulum), and overall brain volume. Most studies focused on infancy, with 18 of 23 presenting data from the first year of life. Socio-environmental factors are associated with changes in brain grey and white matter, especially in the limbic system and associative areas. These findings underscore the influence of early environments on preterm-born brain development, but long-term impacts remain unclear due to limited data beyond infancy. • Socio-environmental factors impact brain development in preterm-born individuals • Limbic and associative cortices are notably sensitive to socio-environmental factors • Socio-environmental factors shape white matter tracts linked to executive functions • Early life experiences crucially shape brain volume and connectivity development • Long-term studies on external factors on preterm brain development are needed