National Centre for Register-based Research, Department of Economics and Business, School of Business and Social Sciences, Aarhus University, Aarhus, Denmark.
The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus and Copenhagen, Aarhus University, Aarhus, Denmark.
Environ Health Perspect. 2020 Dec;128(12):127011. doi: 10.1289/EHP6729. Epub 2020 Dec 22.
Access to green space has been hypothesized to have a beneficial impact on children's mental well-being and cognitive development. The underlying mechanisms of the mental health benefits of green space are not fully understood, but different pathways have been suggested, such as the psychologically restoring capacities of green space, the ability to facilitate physical activity and social cohesion, and the mitigation of exposure to air pollution.
In this nationwide cohort study, we investigated associations between residential green space in early childhood and a clinical diagnosis of attention deficit hyperactivity disorder (ADHD).
The cohort included individuals, who were born in Denmark between 1992 and 2007 () and followed for a diagnosis of ADHD from age 5, during the period 1997-2016. We used the normalized difference vegetation index (NDVI) as a measure of vegetation greenness surrounding each residential address in a quadratic area of in which the residence was located in the center of the quadrate. Individual exposure to green space was calculated as the average of NDVI surrounding each individual's residential address (or addresses if more than one) between birth and the fifth birthday. Multilevel modeling was used to estimate the incidence rate ratios (IRRs) with 95% confidence intervals (CI) for ADHD, according to exposure level and adjusted for calendar time, age, sex, parental socioeconomic status, neighborhood level socioeconomic status, and urbanicity.
Individuals living in areas defined by sparse green vegetation (lowest decile of NDVI) had an increased risk of developing ADHD, compared with individuals living in areas within the highest decile of NDVI (; 95% CI: 1.46, 1.65). Adjusting for the known confounders attenuated the result, but the association remained (; 95% CI: 1.13, 1.28).
Our findings suggest that lower levels of green space in residential surroundings, during early childhood, may be associated with a higher risk of developing ADHD. https://doi.org/10.1289/EHP6729.
人们推测，接触绿色空间对儿童的心理健康和认知发展有益。虽然绿色空间对心理健康的益处的潜在机制尚未完全了解，但已经提出了不同的途径，例如绿色空间的心理恢复能力、促进身体活动和社会凝聚力的能力以及减轻空气污染暴露的能力。
在这项全国性的队列研究中，我们调查了儿童早期居住的绿色空间与注意力缺陷多动障碍（ADHD）临床诊断之间的关联。
该队列包括 1992 年至 2007 年期间在丹麦出生的个体，并在 1997 年至 2016 年期间跟踪 ADHD 诊断。我们使用归一化差异植被指数（NDVI）作为衡量居住地址周围植被绿色度的指标，该植被指数围绕居住地址的正方形区域为 。个体的绿色空间暴露量计算为出生至 5 岁期间个人居住地址（如果有多个地址，则为多个地址）周围的 NDVI 平均值。使用多水平模型根据暴露水平和日历时间、年龄、性别、父母社会经济地位、邻里社会经济地位和城市化程度来估计 ADHD 的发病率比（IRR）及其 95%置信区间（CI）。
与居住在 NDVI 最高十分位数（NDVI 最低十分位数）的个体相比，居住在稀疏绿色植被（NDVI 最低十分位数）定义的区域中的个体发生 ADHD 的风险增加（；95%CI：1.46，1.65）。调整已知混杂因素后，结果减弱，但关联仍然存在（；95%CI：1.13，1.28）。
我们的研究结果表明，儿童早期居住环境中绿色空间水平较低可能与 ADHD 发病风险增加有关。
