Studies on the association between surrounding greenspace and being overweight in childhood show inconsistent results, possibly because they differ widely in their definition and measurement of surrounding greenspace. Our aim was to evaluate whether the association of greenspace with being overweight depends on the measurement of greenspace in different data sources. Based on data from the school entry examinations of 22,678 children in the city of Hannover, Germany, from 2010 to 14, the association between greenspace availability and overweight was examined. Three different sources of greenspace availability were derived for a set of 51 areas of the city: The Normalized Difference Vegetation Index (NDVI), the OpenStreetMap (OSM) dataset, and the European Urban Atlas (UA) dataset. Agreement between the indicators on the quantity of greenspace coverage was compared. The association with children's BMI z-score, including potential interaction terms, was assessed using multilevel regression analysis. Greenspace availability per district area derived by NDVI was on average 42%, by OSM 29% and UA 22%, with OSM and UA being strongly correlated. Only the greenspace availability derived by NDVI showed an association with children's BMI z-score: The higher the greenspace availability was, the lower the BMI. The trend of association was higher for boys and migrant children than for girls and non-migrants and was restricted to the highest levels of greenspace availability. Associations of greenspace with children's weight status depend on the greenspace measurement chosen. Surrounding greenspace was measured more comprehensively by NDVI. Data sources based on land use categories such as UA and OSM may be less suitable to reflect surrounding greenspace relevant for health outcomes. Potential mechanisms warrant further analysis and investigation.

中文翻译：

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通过检查周围绿地与儿童体重状态之间的关联来比较不同的数据源

关于周围绿地与童年超重之间关联的研究显示出不一致的结果，可能是因为它们对周围绿地的定义和测量差异很大。我们的目的是评估绿地与超重的关联是否取决于对不同数据源中绿地的测量。根据 2010 年至 14 年德国汉诺威市 22,678 名儿童入学考试的数据，研究了绿地可用性与超重之间的关联。为城市的 51 个区域得出了三种不同的绿地可用性来源：归一化差异植被指数 (NDVI)、OpenStreetMap (OSM) 数据集和欧洲城市地图集 (UA) 数据集。比较了绿地覆盖数量指标之间的一致性。使用多级回归分析评估与儿童 BMI z 分数的关联，包括潜在的交互项。NDVI 得出的每个地区的绿地可用性平均为 42%，OSM 为 29%，UA 为 22%，OSM 和 UA 密切相关。只有 NDVI 得出的绿地可用性显示与儿童的 BMI z 分数相关：绿地可用性越高，BMI 越低。男孩和移民儿童的关联趋势高于女孩和非移民儿童，并且仅限于最高水平的绿地可用性。绿色空间与儿童体重状况的关联取决于所选的绿色空间测量。NDVI 更全面地测量了周围的绿地。基于土地利用类别（例如 UA 和 OSM）的数据源可能不太适合反映与健康结果相关的周围绿地。潜在的机制需要进一步的分析和调查。