Exposure to green spaces has been linked to both health benefits (increasing physical activity and obesity) and risks (asthma, allergy) in children, but the evidence is inconsistent. Studies looking at both benefits and risks simultaneously, especially in association with different types of greenness, are scarce. The purpose of this study was to evaluate both health benefits and risks to children associated with different types of greenness in terms of sedentary behavior (excessive screen time), obesity, current asthma, and allergy symptoms.
This was a cross-sectional study of 3,178 schoolchildren (9-12 years old) in Spain. Outcomes and covariates were measured by questionnaire (PARENT?). Greenness surrounding each child's home was calculated as the average of satellite-derived Normalized Difference Vegetation Index (NDVI) in buffers of 100 m, 250 m, 500 m, and 1000 m. Proximity of the home to green spaces was defined as living within 300 m of a forest or 300m of a park (within a 15 minute walk). Logistic regression was used to estimate the relationship between each exposure-outcome pair, adjusted for relevant covariates.
The authors found a relationship between greenness and prevalence of overweight/obesity and screen time, but not between greenness and current asthma and allergy symptoms. Similarly, proximity of the home to a forest was associated with lower rates of excessive screen time and overweight/obesity. There was not an association with asthma. However, living close to a park was associated with a higher rate of current asthma, but was not significantly associated with obesity/overweight or excessive screen time. The authors conclude that there can be distinct patterns of health benefits and risks depending on the types of greenness measured.
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