Greater greenness levels around schools are significantly associated with lower odds of ADHD symptoms

Yang, B. -Y., Zeng, Z. -W., Markevych, I., Bloom, M. S., Heinrich, J., Knibbs, L. D., et al. (2019). Association between greenness surrounding schools and kindergartens and attention-deficit/hyperactivity disorder in children in China. Jama Network Open, 2.

Attention-deficit/hyperactivity disorder (ADHD) is associated with a range of negative outcomes for individuals, families, and societies. ADHD is also one of the most common neurobehavioral conditions in childhood. Since environmental factors are associated with ADHD and are generally modifiable, identifying such factors may be useful for reducing ADHD symptoms. This study investigated the association between one such factor – i.e., greenness around schools or kindergartens in China -- and symptoms of ADHD in children attending those schools or kindergartens.

Data for this study was collected between April 2012 and January 2013 in seven cities in northeastern China. Participants included 59,754 children (age 2-17) from 94 schools and kindergartens. All of the participants had resided in the study area for a minimum of two years. The data included two measures of greenness around schools and two parent reports of ADHD symptoms. The greenness measures consisted of the normalized difference vegetation index and the soil-adjusted vegetation index. Scales used to measure ADHD symptoms assessed inattention symptoms and hyperactivity-impulsivity symptoms.

Results showed that levels of greenness varied widely across sites and that 2566 participants (4.3%) had ADHD symptoms. When levels of greenness were linked to incidence of ADHD, results showed that greater greenness levels were significantly associated with lower odds of ADHD symptoms. Statistical analysis of the data showed that “each 0.1-unit increase in normalized difference vegetation index within 500 m of a school and soil-adjusted vegetation index within 500 m of a school was associated with reduced odds of being reported to have at least 6 symptoms of ADHD." Sociodemographic factors (such as gender, household income, or dog ownership) did not modify this association.

These findings suggest that there may be a beneficial association between greenness around schools and ADHD symptoms in Chinese children. These findings also support the increasing scientific interest in the interface between nature exposure and children's overall well-being. While further research is needed, enough is known to support the increased inclusion of green spaces around schools. Such initiatives may help alleviate the burden of ADHD symptoms for children, families, and societies.

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