Background

The epidemiological evidence on green spaces and obesity is inconsistent.

Objectives

To study the association of access to green spaces and surrounding greenness with obesity in Spain.

Methods

We enrolled 2354 individuals 20–85 years from urban areas of seven provinces of Spain between 2008–13. Subjects were randomly selected population controls of the MCC-Spain case-control study. We geocoded current residences and defined exposures in a buffer of 300 m around them: i) access to green space, identified using Urban Atlas, and ii) levels of surrounding greenness, measured by the Normalized Difference Vegetation Index. We examined excess weight/obesity as binary outcomes based on body mass index and waist-hip ratio. We examined effect modification by genetic factors, sex and individual socio-economic status and mediation by physical activity and concentrations of PM_2.5 and NO₂. To assess potential effect modification by genetic factors, we used a polygenic risk score based on obesity polymorphisms detected in genome-wide association studies. We used logistic mixed-effects models with a random effect for catchment area adjusted for potential confounders.

Results

Access to green space was associated with a reduced risk of excess weight/obesity after adjusting for confounders [excess weight: OR (95%CI) = 0.82 (0.63, 1.07), p-value = 0.143; abdominal obesity: OR (95%CI) = 0.68 (0.45, 1.01), p-value = 0.057]. In the stratified analysis, this association was only observed in women. Associations between surrounding greenness and excess weight/obesity were null or modest based on a 1 IQR increase in NDVI [excess weight: OR (95%CI) = 0.99 (0.88, 1.11), p-value = 0.875; abdominal obesity: OR (95%CI) = 0.91 (0.79, 1.05), p-value = 0.186]. The observed associations were not mediated by physical activity or air pollution.

Discussion

Access to green space may be associated with decreased risk of excess weight/obesity among women in Spain. Mechanisms explaining this association remain unclear.

中文翻译：

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西班牙的绿色空间，超重和肥胖

背景

关于绿色空间和肥胖症的流行病学证据不一致。

目标

在西班牙研究进入绿色空间和周围的绿色与肥胖之间的关系。

方法

在2008-13年间，我们从西班牙七个省的城市地区招募了2354名20-85岁的人。受试者是随机选择的MCC-西班牙病例对照研究的人群对照。我们对当前住所进行了地理编码，并在其周围300 m的缓冲区中定义了暴露量：i）使用Urban Atlas识别的绿色空间，以及ii）归一化植被指数测量的周围绿色程度。我们根据体重指数和腰臀比将超重/肥胖作为二元结局进行了检查。我们研究了遗传因素，性别和个体社会经济地位的影响，以及体育锻炼和PM _2.5和NO ₂浓度的介导作用。。为了评估遗传因素对潜在效应的影响，我们基于在全基因组关联研究中发现的肥胖多态性，使用了多基因风险评分。我们使用了Logistic混合效应模型，对流域面积进行了随机影响，并针对潜在的混杂因素进行了调整。

结果

调整混杂因素后，进入绿色空间可减少体重过重/肥胖的风险[体重过重：OR（95％CI）= 0.82（0.63，1.07），p值= 0.143；腹部肥胖：OR（95％CI）= 0.68（0.45，1.01），p值= 0.057]。在分层分析中，这种关联仅在女性中观察到。基于NDVI的1 IQR增加，周围绿色与超重/肥胖之间的关联为零或适度[超重：OR（95％CI）= 0.99（0.88，1.11），p值= 0.875；腹部肥胖：OR（95％CI）= 0.91（0.79，1.05），p值= 0.186]。观察到的关联不是由体育活动或空气污染介导的。

讨论

进入绿色空间可能与降低西班牙女性体重过多/肥胖的风险有关。解释这种关联的机制仍不清楚。