Vitamin D is used for preventing and treating rickets, a disease that is caused by not having enough vitamin D (vitamin D deficiency) Vitamin D is also used for treating weak bones , bone pain, bone loss in people with a condition called hyperparathyroidism Vitamin D is also used for preventing falls and fractures in people at risk for osteoporosis, and preventing low calcium and bone loss in people with kidney failure Vitamin D is used for conditions of the heart and blood vessels, including high blood pressure and high cholesterol Vitamin D is also used for diabetes, obesity, muscle weakness, multiple sclerosis, rheumatoid arthritis, chronic