The association between early life greenness and child cognition is not well understood. Using prospective data from Project Viva (n=857) from 1999 to 2010, we examined associations of early life greenness exposure with mid-childhood cognition. We estimated residential greenness at birth, early childhood (median age 3.1y), and mid-childhood (7.8y) using 30m resolution Landsat satellite imagery [Normalized Difference Vegetation Index]. In early childhood and mid-childhood, we administered standardized assessments of verbal and nonverbal intelligence, visual-motor abilities, and visual memory. We used natural splines to examine associations of early life-course greenness with mid-childhood cognition, adjusting for age, sex, race, income, neighborhood socioeconomic status, maternal intelligence, and parental education. At lower levels of greenness (greenness<0.6), greenness exposure at early childhood was associated with a 0.48% increase in non-verbal intelligence and 2.64% increase in visual memory in mid-childhood. The association between early childhood greenness and mid-childhood visual memory was observed after further adjusting for early childhood cognition and across different methodologies, while the association with non-verbal intelligence was not. No other associations between early life-course greenness and mid-childhood cognition were found. Early childhood greenness was nonlinearly associated with higher mid-childhood visual memory. Our findings highlight the importance of nonlinear associations between greenness and cognition.
Am J Epidemiol
Early Life Exposure to Green Space and Mid-childhood Cognition in the Project Viva Cohort (Massachusetts, USA).