Association between indoor-outdoor green features and psychological health during the COVID-19 lockdown in Italy: A cross-sectional nationwide study

Exposure to public green spaces was shown to be associated with psychological health. Nonetheless, evidence is lacking on the role of different green features within and/or surrounding the home environment when public green spaces are inaccessible or not usable. The overarching goal of this study is to shed light on the associations between the presence of greenness within the home and in the surrounding environment and the detrimental effects of quarantine on psychological health during the COVID-19 pandemic lockdown in Italy. A cross-sectional nationwide study involving an online survey was conducted of an Italian population-based sample of 3886 respondents on the association of indoor and outdoor green features (i.e., presence of plant pots, sunlight, green view and accessibility of private green space and natural outdoor environment) with self-reported increases in anxiety, anger, fear, confusion, moodiness, boredom, irritability, recurrent thoughts and/or dreams, poor concentration and sleep disturbance during the COVID-19 lockdown. Single-exposure regression models were performed to estimate associations between single green features and each psychological health outcome adjusted for relevant covariates. In the adjusted models, the presence of plant pots at home was associated with a lower self-reported increase in anxiety, anger, fear, irritability, and sleep disturbance. A greater amount of sunlight in the home was associated with a lower increase in anger, fear, confusion, moodiness, boredom, irritability, poor concentration, and sleep disturbance. A greater amount of green view and access to private green spaces were both associated with a lower increase in each of the psychological health outcomes except for green view and recurrent thought and/or dreams. Natural outdoor environment was associated with anxiety, fear, boredom, irritability, and sleep disturbance. Significant associations remained robust when adjusted for number of confirmed COVID-19 cases. Insights on future investigations are provided.