Vitamin D is a fat soluble vitamin in the body that is used for bone development and the regulation of calcium.
About 1 billion people in the world have vitamin D deficiency and 50% of the population has vitamin d insufficiency.
Vitamin D deficiency is caused by various things including, reduced absorption, decreased intake, resistance or increased breakdown of vitamin D.
Vitamin D deficiency usually does not present with symptoms, however if severe prolonged deficiencies patients may exhibit signs of hyperparathyroidism. Symptoms include muscle aches, joint aches, muscle twitching, weakness and fatigue.
Children with vitamin D deficiency may present with irritability, lethargy, developmental delay, bone changes, or fractures.
There is some controversy with what is the exact number for deficiency however the goal should be between 20-40 ng/mol.
We diagnose Vitamin D deficiency by measuring the amount of serum 25-hydroxyvitamin D in the body through blood, under 12 is defined as deficiency and insufficiency is considered between 12-20 ng/mL.
If the vitamin D levels are very low it increases the risk of osteomalacia, or softening of the bones.
Those with very low vitamin D should prompt further evaluation by measuring calcium, phosphorus, alkaline phosphatase, parathyroid hormone (PTH), blood urea nitrogen (BUN), creatinine, and tissue transglutaminase antibodies (to assess for celiac disease), and electrolytes such as sodium and potassium.
Vitamin D deficiency should be treated with 50,000 IU of vitamin D. This is given once per week for 8 weeks.
Vitamin D insufficiency is treated with 800-1000 IU of vitamin D daily.