Moving to greener pastures: Health selection into neighborhood green space among a highly mobile and diverse population in California.

Global urbanization has sparked substantial environmental, public health, and social science research on the importance of conserving and propagating natural environments. A large subset of this work focuses on the benefits of green space for health. An often-overlooked methodological concern when examining relations between green space and health, however, involves residential self-selection. The selective movement of individuals into greener neighborhoods on the basis of preexisting health and correlated social factors may bias associations, particularly in cross-sectional studies, which predominate existing green space/health research. To quantify the extent of residential self-selection bias, this study used a longitudinal sibling comparison design with repeated individual and neighborhood measures to estimate associations between pre-move health factors, including maternal body mass index (BMI) and infant birthweight, and post-move neighborhood green space in a residentially mobile sample of mothers in California, 2007 to 2015 (n = 288,333). Results show that better health before moving predicted higher levels of neighborhood green space after moving, providing evidence of health selection. Findings also indicate some support for differential health selection into neighborhood green space by race/ethnicity, including that evidence of selection emerges for white and Hispanic, but not Black, mothers. However, weak relations between pre-move individual factors and post-move neighborhood green space across analyses suggest that potential bias due to residential self-selection appears relatively minimal in a large, diverse, and highly mobile sample of families in California. Findings support calls to increase green space in historically marginalized neighborhoods as a means to promote environmental and health equity.