Table 2.

Association between markers of green and blue space and relative odds of preterm birth (95% confidence intervals) among 61,640 births in Rhode Island.

	Unadjusted	+adjustment for patient demographics and markers of individual SES^b	+ adjustment for markers of neighborhood SES^c	+adjustment for town of residence^d	+ adjustment for all other available environmental variables^e
NDVI (500 m buffer)^a	0.96 (0.92, 1.01)	1.09 (1.03, 1.16)^**	1.12 (1.04, 1.20)^**	1.02 (0.92, 1.13)	1.01 (0.91, 1.13)
Proximity to recreational facilities (500 m)	1.01 (0.95, 1.07)	0.93 (0.87, 0.996)^*	0.93 (0.87, 0.99)^*	0.97 (0.91, 1.05)	1.00 (0.98, 1.01)
Proximity to coast (1000m)	0.99 (0.92, 1.07)	1.02 (0.95, 1.10)	1.02 (0.94, 1.09)	1.02 (0.93, 1.12)	1.00 (0.98, 1.03)
Proximity to coast (500m)	0.98 (0.89, 1.08)	1.01 (0.92, 1.12)	1.01 (0.91, 1.12)	1.00 (0.89, 1.12)	1.00 (0.97, 1.03)
Proximity to freshwater (500m)	0.98 (0.92, 1.04)	0.97 (0.91, 1.04)	0.97 (0.91, 1.04)	0.94 (0.88, 1.01)	0.99 (0.97, 1.00)

significant at p<0.05,

^**

significant at p<0.01;

^***

significant at p<0.001;

Odds ratios are per one interquartile range increase in NDVI;

Adjusted for mother’s age, prenatal visits, tobacco use, parity, education, race, insurance, and marital status;

Adjusted for variables in^b plus NSES z-score;

Adjusted for variables in^c plus town of residence

Adjusted for variables in^d plus (except when variable is the exposure of interest) NDVI (500 m buffer), residential proximity within 500 meters of a recreational facility, residential proximity within 1,000 meters of the coast, residential proximity within 500 meters of a freshwater body, and residential proximity to roadways (within 150 m of an A2 roadway or within 50 m of an A1 roadway).