I never realized until I was diagnosed with a serious Vitamin D deficiency what all problems this could cause. My doctor was very concerned because my levels were dangerously low and he immediately put me on a high dose Vitamin D supplement. Some other health problems my doctor told me Vitamin D deficiency could cause include heart disease, chronic pain, Fibromyalgia, hypertension, arthritis, depression, inflammatory bowel disease, obesity, PMS, Crohns Disease, cancer, MS and other autoimmune diseases.