It's Sunny, Be Healthy? An International Comparison of the Influence of Sun Exposure and Latitude Lines on Self-Rated Health.

The positive impact of sunshine on self-rated health is well known. For the first time, the relationship between sunshine and self-rated health is examined in the context of latitude lines in international comparison. The further people live from the equator, the lower sun exposure (UVB exposure) and the more often they experience a vitamin D deficiency. UVB exposure decreases with degrees of latitudinal lines, and in addition to that, sunshine duration is shorter in northern countries. In order to consider the connection, sunshine duration and degree of latitude lines were manually enriched from the German Meteorological Service (Deutscher Wetterdienst) to the International Social Survey Programs (2011): Health and Health Care and analyzed with a logistic multilevel model, as well as the inclusion of sunshine duration as a mediator. If sunshine hours, as well as latitude lines, are considered separately in models, both show a statistically significant effect. Together in one model, the sunshine hours lose their relationship and additionally there is no mediation. This suggests that the location of the region is the decisive component when considering self-rated health. Furthermore, an interaction between age and sunshine hours as well as latitude lines is also shown.