Residential exposure to green and blue spaces over childhood and cardiometabolic health outcomes: The generation XXI birth cohort

Evidence on the effects of green and blue spaces on childhood cardiometabolic health is inconsistent and mostly cross-sectional. We assessed the associations of green and blue spaces exposure at birth 4, 7, and 10 years (to identify vulnerable periods of exposure) and as longitudinal trajectories (to identify the longitudinal effect over time) with cardiometabolic outcomes at 10 years. Among 4669 participants from a population-based birth cohort, we assessed the residential normalized difference vegetation index (NDVI) and distance to urban green and blue spaces at each time point using geographic information systems and standardized by dividing the observed value by the standard deviation. Longitudinal exposure trajectories were derived using latent class mixed models. At 10 years, we measured body mass index, fat mass index, android-to-gynoid fat ratio, blood pressure, and metabolic outcomes. We defined overweight/obesity (World Health Organization), high blood pressure (American Academy of Pediatrics), and metabolic syndrome (IDEFICS). No significant associations were observed between natural spaces exposure and adiposity outcomes. We found an inverse association between distance to nearest blue space at birth and systolic blood pressure z-scores, and a positive association between distance to nearest green space at 7 and 10 years and metabolic syndrome score (p < 0.05). Children in the descending NDVI500m trajectory, compared to those in the high stable trajectory, showed lower diastolic blood pressure z-scores and metabolic syndrome scores (p < 0.05). However, after multiple testing corrections, all associations lost statistical significance. This study did not find robust associations between natural spaces during key developmental periods and cardiometabolic health.