Associations between multiple green space measures and birth weight across two US cities

Area of Science:

• Environmental Epidemiology
• Urban Health
• Reproductive Health

Background:

• Epidemiological studies use various green space metrics, but their health relevance and exposure pathways are unclear.
• Understanding urban green space's impact on birth weight is crucial for public health initiatives.

Purpose of the Study:

• To examine associations between multiple urban green space metrics and term birth weight.
• To investigate how individual and contextual factors modify these associations across two diverse US cities.

Main Methods:

• Birth cohort data (2005-2009) from Portland, Oregon, and Austin, Texas.
• Green space metrics included NDVI, % tree cover, % green space, % street tree buffering, and park access at multiple buffer distances.
• Mixed models controlled for individual and neighborhood factors to assess associations with term birth weight.

Main Results:

• Unadjusted models showed protective effects of green space on birth weight, but these diminished after controlling for confounders.
• Maternal race, ethnicity, and education most significantly reduced green space-birth weight associations.
• Positive associations were observed in high-density areas with specific green space metrics at small buffer distances.

Conclusions:

• The relationship between green space and birth weight is complex and influenced by individual and contextual factors.
• Future research should account for confounders and modifiers to accurately assess green space's health impacts.