Exposure to neighborhood green space and sleep: evidence from the Survey of the Health of Wisconsin.

INTRODUCTION: Adequate sleep duration and quality are protective against many adverse health outcomes. Many individual-level predictors of poor sleep have been examined, but few studies have examined neighborhood-level influences. Despite known associations between neighborhood green space and sleep influencing factors (eg, physical activity, mental health), few studies have examined green space and sleep's relationship. Furthermore, little work has examined the relationship between the magnitude and type of neighborhood sounds and sleep.

STUDY METHODS: We analyzed data from the Survey of the Health of Wisconsin database (n = 2712) for 2008-2013, a representative sample of Wisconsin residents ages 21-74. Outcomes included weekday and weekend sleep duration and self-rated sleep quality. Primary predictors were the proportion tree canopy (National Land Cover Database) and mean decibel levels of outdoor sound (US National Park Service) at the census block group level. Survey regression analysis was used to examine statistical associations, controlling for individual and neighborhood-level covariates.

RESULTS: Models suggest a significant relationship (P < .05) between weekday sleep duration and green space, and between weekend/day sleep duration and human-made and total neighborhood sound. Increased percent tree canopy in a census block group was associated with lower odds of short weekday sleep (<6 hours) (OR 0.76 [0.58-0.98]). Increased human-made and total mean decibel levels were associated with increased instances of short weekend and weekday sleep (OR 1.05 [1.01-1.08] and 1.03 [1.01-1.06] respectively).

CONCLUSIONS: Neighborhood tree canopy and sound levels may influence sleep duration and are potential targets for neighborhood-level interventions to improve sleep.