Association between greenness, urbanicity, and birth weight

Abstract

Background More than half of the world's population lives in urban environments. Due to urban related factors (e.g. higher air pollution), urban residents may face higher risk of adverse health outcomes, while access to green space could benefit health. Purpose We explored associations between urban and green land-use and birth weight. Methods Connecticut, U.S., birth certificate data (2000-2006) were acquired (n=239,811), and land-use data were obtained from the National Land Cover Database. We focused on three land-uses; urban space, urban open space, and green space (i.e. forest, shrub, herbaceous, and cultivated land). We estimated fractions of greenness and urbanicity within 250 m from residence. A linear mixed effects model was conducted for birth weight and a logistic mixed effects model for low birth weight (LBW) and small for gestational age (SGA). Results An interquartile range (IQR) increment in the fraction of green space within 250 m of residence was associated with 3.2g (95% Confidence Interval [0.4, 6.0]) higher birth weight. Similarly, an IQR increase in green space was associated with 7.6% [2.6, 12.4] decreased risk of LBW. Exposure to urban space was negatively correlated with green space (Pearson correlation = −0.88), and it showed negative association with birth outcomes. Results were generally robust with different buffer sizes and controlling for fine particles (PM2.5) and traffic. Conclusions We found protective associations by green space on birth outcomes. Increasing green space and/or reducing urban space (e.g. the greening of city environments) may reduce the risk of adverse birth outcomes such as LBW and SGA. Populations living in urban environments will grow in the next half century, and allocation of green space among urban areas may play a critical role for public health in urban planning.

Residential greenness: current perspectives on its impact on maternal health and pregnancy outcomes

“…Results were mixed, but multiple studies found stronger associations between greenness and birth outcomes in participants or neighborhoods of lower socioeconomic status 12–14,16,20. These findings suggest that the potential benefits of greenness on health may be strongest in more deprived areas.…”

A Review of Epidemiologic Studies on Greenness and Health: Updated Literature Through 2017

“…A limited number of studies have quantified exposure to green spaces (e.g., parks) using land cover datasets to assess, for instance, the proportion of parks in a participant’s administrative boundary (e.g., Census tract) or within a given radius from the subject’s address [13,15,16,18–24]. Other studies have assessed the road network distance between a participant’s home address and green spaces such as parks, forests, agricultural land, and others [10,14,16,25–28].…”

“…In analyses stratified by season of birth, the authors observed a negative correlation between NDVI and birth weight in births that occurred during warmer months (April-June). While other studies also found positive associations between greenness and higher birth weights overall [12,13], some studies found either positive associations that were not formally statistically significant [11], more importantly effect estimates moved towards the null with adjustment for covariates [12], and some study results were inconsistent depending on the greenness measure or outcome assessed [10,25]. The birth cohort studies encompassed diverse geographical settings, and effect sizes varied by region.…”

Public health in linkage to land use: Theoretical framework, empirical evidence, and critical implications for reconnecting health promotion to land use policy

“…In addition, better health outcomes are observed in neighborhood with greater area devoted to health facilities (e.g., clinics and hospitals) and institutional land (e.g., schools, square, and community centers) (Brown et al, 2009;Mobley et al, 2008). On the contrary, increased urban land use is reported to significantly associate with rising risk of adverse birth outcomes (e.g., small gestational age and low birth weight) (Ebisu et al, 2016) and asthma symptoms (Son et al, 2015). Some cases move from the urban areas to the rural places.…”