Data from: Natural light exposure, sleep and depression among day workers and shiftworkers at Arctic and Equatorial latitudes

Objectives: This study aimed to investigate the relationship between
individual natural light exposure, sleep need, and depression at two
latitudes, one extreme with a few hours of light per day during winter,
and the other with equal hours of light and darkness throughout the year.
Methods: This cross-sectional study included a sample of Brazilian workers
(Equatorial, n = 488 workers) and a Swedish sample (Arctic, n = 1,273).
Results: The reported mean total natural light exposure per 4-week cycle
differed significantly between the Equatorial and Arctic regions. However,
shiftworkers from both sites reported similar hours of natural light
exposure. Short light exposure was a predictor for insufficient sleep.
Conclusion: Reduced exposure to natural light appears to increase the
perception of obtaining insufficient sleep. Arctic workers were more prone
to develop depression than Equatorial workers.