Although vitamin D is obtained from diet and dietary supplements, the main source of vitamin D is production in our skin under the influence of solar radiation.
As sun exposure varies with the latitude of regions and during the year, so vitamin D concentrations of populations vary accordingly. Furthermore, women are generally more prone to low vitamin D concentrations than men. Vitamin D deficiency is especially common among the elderly who often have less sun exposure because of reduced outdoor activity and reduced capacity of the skin to produce vitamin D.
Research on Vitamin D’s Protective Role
We conducted an international study of eight populations from Europe and the United States to investigate the association of level of vitamin D in blood and deaths from all-causes, cardiovascular diseases, and cancer mortality, published in the British Medical Journal in June 2014. We paid attention to differences between countries, sexes, age groups and seasons of blood sampling. The study was conducted with the CHANCES Project, a research initiative funded by the European Commission and coordinated by scientists at the Hellenic Health Foundation in Athens, Greece, and Mount Sinai School of Medicine in New York, and primary authors were from the German Cancer Research Center, in Heidelberg.