Wen-Wen Bao1, Bo-Yi Yang2, Zhi-Yong Zou3, Jun Ma3, Jin Jing1, Hai-Jun Wang4, Jia-You Luo5, Xin Zhang6, Chun-Yan Luo7, Hong Wang8, Hai-Ping Zhao9, De-Hong Pan10, Zhao-Huan Gui1, Jing-Shu Zhang1, Yu-Ming Guo11, Ying-Hua Ma12, Guang-Hui Dong13, Ya-Jun Chen14. 1. Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China. 2. Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Guangdong Provincial Engineering Technology Research Center of Environmental and Health Risk Assessment, Department of Preventive Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China. 3. Institute of Child and Adolescent Health, School of Public Health, Peking University, Beijing, 100191, China. 4. Department of Maternal and Child Health, School of Public Health, Peking University, Beijing, 100191, China. 5. Department of Maternal and Child Health, School of Public Health, Central South University, Changsha, 410078, China. 6. School of Public Health, Tianjin Medical University, Tianjin, 300070, China. 7. Shanghai Municipal Center for Disease Control and Prevention, Shanghai Institute of Preventive Medicine, Shanghai, 200336, China. 8. Department of Maternal and Child Health, School of Public Health and Management, Chongqing Medical University, Chongqing, 400016, China. 9. School of Public Health and Management, Ningxia Medical University, Ningxia, 750004, China. 10. Liaoning Health Supervision Bureau, Shenyang, 110005, China. 11. Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, 3004, Australia. 12. Institute of Child and Adolescent Health, School of Public Health, Peking University, Beijing, 100191, China. Electronic address: yinghuama@bjmu.edu.cn. 13. Guangzhou Key Laboratory of Environmental Pollution and Health Risk Assessment, Guangdong Provincial Engineering Technology Research Center of Environmental and Health Risk Assessment, Department of Preventive Medicine, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: donggh5@mail.sysu.edu.cn. 14. Department of Maternal and Child Health, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China. Electronic address: chenyj68@mail.sysu.edu.cn.
Abstract
BACKGROUND: Previous studies have indicated that exposure to green space may benefit human health. However, the available evidence concerning the effects of greenness, especially school-based greenness, on pediatric obesity is scarce. OBJECTIVE: To explore the association between school-based greenness and adiposity in children and adolescents in China. METHOD: We conducted a nationwide cross-sectional study of 56,620 children and adolescents (aged 6-18 years) in seven provinces/municipalities across China. School-based greenness was assessed using satellite-derived Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) within 100-, 500-, and 1000-m circular buffers around each school's address. Generalized linear mixed regression models were used to estimate associations of greenness with BMI z-scores (zBMI), waist circumference, and prevalent overweight/obesity. We also explored the potential mediating role of ambient air pollution and physical activity in the greenness-adiposity associations. RESULT: In the adjusted model, an IQR increase in NDVI-1000m was associated with lower zBMI (β: -0.11, 95% confidence interval[CI]: -0.13,-0.09) and waist circumference (β: -0.64, 95%CI: -0.78,-0.50). Consistently, an IQR increase in NDVI-100m, NDVI-500m, NDVI-1000m was associated with 7-20% lower odds of overweight/obesity in the adjusted models. Air pollutants mediated 6.5-29.1% of the association between greenness and zBMI. No significant mediation effect was observed for physical activity. CONCLUSION: Higher school-based greenness levels were associated with lower zBMI, waist circumference, and lower odds of overweight and obesity in children and adolescents. Ambient air pollutants may partially mediate the greenness-adiposity associations.
BACKGROUND: Previous studies have indicated that exposure to green space may benefit human health. However, the available evidence concerning the effects of greenness, especially school-based greenness, on pediatric obesity is scarce. OBJECTIVE: To explore the association between school-based greenness and adiposity in children and adolescents in China. METHOD: We conducted a nationwide cross-sectional study of 56,620 children and adolescents (aged 6-18 years) in seven provinces/municipalities across China. School-based greenness was assessed using satellite-derived Normalized Difference Vegetation Index (NDVI) and Soil Adjusted Vegetation Index (SAVI) within 100-, 500-, and 1000-m circular buffers around each school's address. Generalized linear mixed regression models were used to estimate associations of greenness with BMI z-scores (zBMI), waist circumference, and prevalent overweight/obesity. We also explored the potential mediating role of ambient air pollution and physical activity in the greenness-adiposity associations. RESULT: In the adjusted model, an IQR increase in NDVI-1000m was associated with lower zBMI (β: -0.11, 95% confidence interval[CI]: -0.13,-0.09) and waist circumference (β: -0.64, 95%CI: -0.78,-0.50). Consistently, an IQR increase in NDVI-100m, NDVI-500m, NDVI-1000m was associated with 7-20% lower odds of overweight/obesity in the adjusted models. Air pollutants mediated 6.5-29.1% of the association between greenness and zBMI. No significant mediation effect was observed for physical activity. CONCLUSION: Higher school-based greenness levels were associated with lower zBMI, waist circumference, and lower odds of overweight and obesity in children and adolescents. Ambient air pollutants may partially mediate the greenness-adiposity associations.