Data on 3203 newborns in Germany was examined to investigate the positive association between surrounding greenness and birth weight. Previous studies had established such an association but the underlying mechanisms remained unclear. The aim of this study was to further examine the association and to explore potential explanations for why surrounding greenness at the birth address was associated with more positive birth outcomes.
Participants for this study were from two different birth cohorts in Munich: the GINIplus and the LISAplus cohorts. GINIplus participants were born between 1995 and 1998 and the LISAplus participants between 1996 and 1999. Information on the home address, socioeconomic characteristics of parents, and lifestyle factors was collected by parent-completed questionnaires at the time of birth for both cohorts.
The Normalized Difference Vegetation Index (NDVI) was used to determine surrounding greenness for the home addresses of the mothers. The NDVI is an indicator of green biomass density and uses satellite images to obtain a reading. The local Bavarian land use data set was used to calculate neighborhood green space for these same addresses. Neighborhood green space was defined as forests and parks in a 500-meter buffer around the home.
Birth weight data was analyzed in relation to both surrounding greenness and neighborhood green space. Other factors considered in the analysis included sex of the baby, year and season of birth, maternal age and education level, and maternal smoking during pregnancy. Findings indicated that surrounding greenness in a 500-m buffer was associated with an average birth weight increase of 17.6 g and that this association was strongest for children born to mothers with less than 10 years of school. The association between surrounding greenness and birth weight was not significant for children born to mothers with at least 10 years of school. Access to neighborhood green space was not associated with birth weight. According to the authors, the mechanisms behind the association between greenness and birth weight remain unclear and warrant further study.
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