Vitamin D deficiency can cause a range of health problems, including issues with bones and muscles. Vitamin D is essential for normal bone development and maintenance, and a lack of it can lead to a loss of bone density, which can contribute to osteoporosis and fractures (broken bones) . In older adults, severe vitamin D deficiency may also contribute to an increased risk of falls. Symptoms of vitamin D deficiency can include muscle pain, bone pain, tingly sensation in hands or feet, muscle weakness, depression or feelings of sadness, hair loss, loss of appetite, getting sick more easily, and pale skin. However, many people with vitamin D deficiency are asymptomatic. The two main causes of vitamin D deficiency are not getting enough vitamin D in your diet and not getting enough exposure to sunlight. Other causes include malabsorption problems, liver or kidney failure, certain medications, and certain types of cancer. People who are at higher risk of vitamin D deficiency include those who are obese, those with osteoporosis, and people with malabsorption disorders. Vitamin D deficiency can also lead to other diseases, such as rickets in children and osteomalacia in adults.