Exposure to natural environments may affect respiratory health. This study examined the association of exposure to green and blue spaces with lung function in children, and assessed the mediation effect of air pollution and physical activity.

The study used data from the Generation XXI, a population-based birth cohort from the Porto Metropolitan Area (Portugal). Residential Normalised Difference Vegetation Index (NDVI) at different buffers (100, 250 and 500 m), the accessibility to urban green spaces (UGS) within 400 and 800 m and the minimum distance to the nearest UGS and to the nearest blue spaces were assessed at birth, 4, 7 and 10 years of age. Three life-course measures were calculated: averaged exposure, early-life exposure (birth) and exposure trend over time (change in exposure). Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and forced expiratory flow between 25% and 75% of FVC (FEF_25–75%) at 10 years were used as outcomes. To assess associations, linear regression models and path analysis were used.

This study included 3278 children. The adjusted models showed that increasing the NDVI exposure over time within 100 m of the child's residence was associated with higher values of FEV₁ (L) and FEF_25–75% (L·s^–1) (β 0.01, 95% CI 0.0002–0.03 and β 0.02, 95% CI 0.001–0.05, respectively). No significant associations were observed for the remaining measures of exposure, and no mediation effect was found for pollution or physical activity.

Increasing exposure to greenness at close proximity from residences was associated with improved lung function. While the mechanism remains unknown, this study brings evidence that city greening may improve children's respiratory health.

暴露于自然环境可能会影响呼吸道健康。这项研究探讨了儿童接触绿色和蓝色空间与肺功能的关系，并评估了空气污染和体力活动的中介作用。

该研究使用了第二十一代的数据，这是一个来自波尔图大都市区（葡萄牙）的人口出生队列。评估了不同缓冲区（100、250和500 m）的住宅归一化植被指数（NDVI）、400和800 m内城市绿地（UGS）的可达性以及到最近UGS和最近蓝色空间的最小距离出生时、4岁、7岁和10岁时。计算了三种生命历程指标：平均暴露、生命早期暴露（出生）和随时间变化的暴露趋势（暴露变化）。用力肺活量 (FVC)、1 秒用力呼气量 (FEV ₁ ) 和 10 年时 FVC 25% 至 75% 之间的用力呼气流量 (FEF _25–75% ) 作为结果。为了评估关联性，使用了线性回归模型和路径分析。

这项研究包括 3278 名儿童。_{调整后的模型显示，随着时间的推移，儿童居住地 100 m 范围内 NDVI 暴露的增加与较高的 FEV 1} (L) 和 FEF _25–75% (L·s ^–1 )值相关（β 0.01，95% CI 0.0002 –0.03 和 β 0.02，95% CI 0.001–0.05）。对于其余的暴露测量，没有观察到显着的关联，也没有发现污染或体力活动的中介效应。

增加居住地附近的绿色环境与改善肺功能有关。虽然其机制尚不清楚，但这项研究提供了证据表明城市绿化可以改善儿童的呼吸系统健康。