Vitamin D Deficiency & Hyperparathyroidism In The Elderly

Vitamin D is a fat-soluble vitamin that is synthesized in the skin under direct sunlight. It exists in two forms -- D2 and D3. Its naturally occurring form, vitamin D3 aids the absorption of calcium from the gut. Vitamin D deficiency typically occurs in winter months when individuals, especially the elderly, spend most of their time indoors and away from sunlight. Vitamin D deficiency is also pronounced with poor dietary intake. A deficiency in vitamin D leads to hypocalcemia, or low blood calcium. Hypocalcemia results in secondary hyperparathyroidism.

Secondary Hyperparathyroidism

Secondary hyperparathyroidism, or excess secretion of parathyroid hormone due to hypocalcemia, is a consequence of vitamin D deficiency. The parathyroid gland is important in the regulation of calcium. It produces parathyroid hormone when calcium is low in the blood. The parathyroid hormone acts in the bones, causing it to breakdown, which releases calcium into the blood. It also prevents the excretion of calcium from the kidneys.

Complications Associated with Low Vitamin D

Low vitamin D resulting from decreased absorption from the intestines or from low dietary intake leads to hypocalcemia. Hypocalcemia bears serious risks, such as irregular pulse and seizures. Vitamin D deficiency is also caused by lack of direct sunlight exposure, especially in the elderly who have limited physical activity. The combined effect of inadequate sunlight exposure and decreased physical activity contributes to a low bone density and weak bones. Weak bones are a result of poor bone mineralization due to low calcium. Bones become softer over time and are more likely to fracture.

Symptoms

Secondary hyperthyroidism leads to increased breakdown of bone to release calcium. This makes the bone fragile and more likely to fracture. Bone and joint pain are chief complaints associated with this disease. Other symptoms may include depression, generalized weakness, nausea and abdominal pain. Vitamin D-associated hypocalcemia can also cause tetany, a condition of uncontrollable muscle contractions. Tetany results in peculiar sensations over the lips, tongue and fingers. Muscles of the face also tend to twitch randomly as well.

Assessment

Suspected vitamin D deficiency in elderly should be handled aggressively. The elderly are prone to falls and fractures. Poor bone health increases the risk of injury. A family physician normally checks the levels of calcium in the elderly to confirm its adequacy in the blood. In the elderly, low blood calcium is suspicious for vitamin D deficiency. The concentration of vitamin D in the blood should be greater than 30 nanograms per milliliter, or ng/mL. If it is less than 30 ng/mL, it is abnormal. Vitamin D is deficient when its concentration in the blood is less than 20 ng/mL.

Treatment and Management

In the elderly, low vitamin D must be addressed by supplementation. Dietary changes and sunlight exposure are recommended as well. The U.S. Department of Health and Human Services recommends supplementing vitamin D at doses of 700 to 800 international units, or IUs, in combination with 500 to 1,200mg of calcium. This combination has reduced the likelihood of fractures associated with falls in the elderly. Dietary modifications should include foods such as fish, eggs, vitamin D-fortified milk and cod liver oil.