Prenatal exposure to green space and mental health in early adolescence: findings from the TRAILS study.

Little is known about whether prenatal green space exposure contributes to mental health later in life. Using data from a Dutch cohort (TRAILS; n=1,476), we assessed associations between prenatal (1989-1991) green space exposure and four mental health outcomes, namely externalizing problems, internalizing problems, tobacco use, and alcohol use, self-reported at eleven-year-old (2001-2002), and mediation of gestational age and birthweight on these associations. In a structural equational model, adolescents with one standard deviation (SD) unit more prenatal green space exposure showed a 0.119 SD (95%CI:0.028,0.210) more externalizing problems in early adolescence. There are two potential explanations for this unexpected positive association. First, controlling for urbanicity attenuated this association to become insignificant, but the degree of attenuation was minor [0.096, (95%CI:-0.003,0.195)]. Second, this unexpected association might be a consequence of changes in green space exposure in the intervening years, namely childhood (from birth to early adolescence), indicating that individuals with increased green space exposure over childhood exhibited fewer externalizing problems in early adolescence. For the prenatal green space-externalizing problems association, we did not observe mediation by gestational age or birthweight. Overall, these findings suggest no beneficial role of prenatal green space on adolescent mental health. Instead, increased green space exposure in childhood may lead to lower externalizing problems in early adolescence.