BACKGROUND A growing number of studies observe associations between the amount of green space around a mother's home and positive birth outcomes; however, the robustness of this association and potential pathways of action remain unclear. OBJECTIVES To examine associations between mother's residential green space and term birth weight within the Canadian Healthy Infant Longitudinal Development (CHILD) study and examine specific hypothesized pathways. METHODS We examined 2510 births located in Vancouver, Edmonton, Winnipeg, and Toronto Canada. Green space was estimated around mother's residences during pregnancy using Landsat 30 m normalized difference vegetation index (NDVI). We examined hypothesized pathways of: (1) reduction of environmental exposure; (2) built environment features promoting physical activity; (3) psychosocial conditions; and (4) psychological influences. Linear regression was used to assess associations between green space and term birth weight adjusting first for a comprehensive set of confounding factors and then incrementally for pathway variables. RESULTS Fully adjusted models showed non-statistically significant increases in term birth weight with increasing green space. For example, a 0.1 increase in NDVI within 500 m was associated with a 21.5 g (95% CI - 4.6, 47.7) increase in term birth weight. Associations varied by city and were most robust for high-density locations. For the two largest cities (Vancouver and Toronto), we observed an increase in birth weight of 41.2 g (95% CI 7.8, 74.6) for a 0.1 increase in NDVI within 500 m. We did not observe substantial reductions in the green space effect on birth weight when adjusting for pathway variables. CONCLUSION Our results highlight the need to further characterize the interactions between green space, urban density and climate related factors as well as the pathways linking residential green space to birth outcomes.

中文翻译：

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加拿大健康婴儿纵向发展（CHILD）研究中的住宅绿地和达到足月出生体重的途径。

背景技术越来越多的研究观察到母亲家庭周围的绿色空间与积极的生育结果之间的联系。然而，这种关联的稳健性和潜在的作用途径仍不清楚。目的在加拿大健康婴儿纵向发展（CHILD）研究中检查母亲居住的绿地与足月出生体重之间的关联，并研究特定的假设途径。方法我们检查了位于温哥华，埃德蒙顿，温尼伯和加拿大多伦多的2510例婴儿。使用Landsat 30 m归一化植被指数（NDVI）估算怀孕期间母亲住所周围的绿地。我们研究了以下假设途径：（1）减少环境暴露；（2）营造促进体育活动的环境特征；（三）社会心理状况；（四）心理影响。线性回归用于评估绿地和足月出生体重之间的关联，首先针对一整套混杂因素进行调整，然后针对路径变量进行递增调整。结果完全调整的模型显示，随着绿地的增加，足月出生体重的增加无统计学意义。例如，在500 m内NDVI增加0.1意味着足月出生体重增加21.5 g（95％CI-4.6，47.7）。协会因城市而异，并且在高密度位置上最有效。对于两个最大的城市（温哥华和多伦多），我们发现出生体重增加了41.2 g（95％CI 7.8，74.6），而500 m之内的NDVI增加了0.1。调整途径变量后，我们没有观察到绿地对出生体重的影响大幅度降低。结论我们的结果强调需要进一步表征绿色空间，城市密度和气候相关因素之间的相互作用以及将住宅绿色空间与出生结果联系起来的途径。