Neighbourhood green space, perceived stress and sleep quality in an urban population

Background: Few studies have investigated the impact of neighbourhood green space on perceived stress and sleep quality with adjustment for other environmental factors such as household traffic noise and ambient air pollution. Methods: From May to August 2017, a cross-sectional survey of pedestrians aged 20 years or over was conducted in Hong Kong. Neighbourhood green space coverage was measured using the normalized difference vegetation index (NDVI) within a 500-metre buffer of individual residential address. Multinomial logistic regression models were applied to assess the effects of green space on sleep quality and perceived stress. Results: We successfully interviewed 608 participants with a mean age of 47.5 years (range 20-99). After adjustment for demographics, lifestyle factors, household air pollution and noise exposure, individuals with more perceived stress had higher odds of moderate and poor sleep quality. This association was found significant in people with low neighbourhood green space coverage, but not in those with high coverage. Conclusion: There is some evidence that green space coverage in neighbourhood can attenuate the adverse effects of perceived stress on sleep quality.