Lack of exposure to adequate sunlight has increased the incidence of Vitamin D deficiency among people. Vitamin D deficiency is associated  with many medical conditions—ranging from the body’s  decreased ability to fight infections to  weaker bones, etc. 
But some common beliefs relating to Vitamin-D deficiency  are unfounded. Take for example the belief that  low levels of vitamin D in the blood can increase the risk of asthma, atopic dermatitis, and elevated total immunoglobulin E (IgE). A recent study published in the Plos journal didn’t find any evidence that proves these associations.