TABLE 2.

Summary of findings

	Built environment characteristics	Number of studies for the specific exposure–outcome		Synthesis of findings
		Total	Significant results	z score	p value
Air pollution	NO2/NOx	n = 11	n = 5.8 (53%)	3.422	0.0006 ***
	PM2.5	n = 8	n = 2.5 (31%)	1.643	0.100
	PM10	n = 5	n = 1.5 (30%)	1.441	0.150
	SO2	n = 2	n = 1.75 (88%)	‐
	O3	n = 1	n = 1 (100%)	‐
Neighborhood walkability	Walkability index	n = 10	n = 1.8 (18%)	1.083	0.279
	Walk score	n = 2	n = 0.2 (10%)	‐	‐
	Walkable streets	n = 1	n = 1 (100%)	‐	‐
	Intersection density	n = 7	n = 3.6 (51%)	2.805	0.005 **
	Residential density	n = 6	n = 1.3 (22%)	1.206	0.223
	Land use mix	n = 4	n = 1 (25%)	‐	‐
Availability and accessibility of parks and playgrounds	Distance to nearest park	n = 9	n = 2.2 (24%)	1.373	0.170
	Park area	n = 10	n = 4 (40%)	2.451	0.014 *
	Number of parks	n = 8	n = 2 (25%)	1.448	0.148
	Presence/absence of parks	n = 5	n = 4 (80%)	3.498	0.0005 ***
	Normalized Difference Vegetation Index (NDVI)	n = 3	n = 1 (33%)	‐	‐
	Playgrounds only (distance, area, presence)	n = 3	n = 0	‐	‐

Note: Total number of studies for each specific exposure–outcome combination (only BMI‐derived outcomes in this case), and the number reporting statistically significant associations, including fractional results to account for mixed findings (e.g., valid only in boys and not in girls = 0.5) with percentages in brackets. z scores and p values are results from the z test. Statistically significative p values are highlighted.

^* p < 0.05—weak evidence.

^** p < 0.01—strong evidence.

^*** p < 0.001—very strong evidence