Outdoor artificial light at night: A forgotten factor in green space and health research.

Exposure to green space has been associated with a range of human health benefits, largely in spatial epidemiological studies. Green space and artificial light at night are both associated with breast and prostate cancer, depressive symptoms, obesity, and sleep problems, and are both influenced by the built environment and urbanisation. We identified a negative correlation between green space diversity and outdoor artificial light at night for Australian major cities. Outdoor artificial light at night is therefore a potential, but overlooked, confounder in spatial epidemiological studies of green space exposure and human health, and should be incorporated into future models.