Insufficient vitamin D levels are a problem for about 50% of people globally. It is believed that 1 billion individuals globally, of all ages and ethnicities, are vitamin D deficient (VDD).
The main causes of this hypovitaminosis D pandemic are environmental and lifestyle variables that limit exposure to sunshine, which is necessary for ultraviolet-B (UVB)-induced vitamin D synthesis in the skin. Examples of these factors include less outdoor activity and air pollution.
Because hypovitaminosis D is an independent risk factor for total mortality in the general population, the high incidence of vitamin D insufficiency is a significant public health concern.
