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Parathyroid hormone levels are affected by a variety of underlying factors. Health conditions such as damage to the parathyroid, autoimmune disorders and low blood magnesium will most likely cause low parathyroid levels. When elevated or high parathyroid levels are present, vitamin deficiency, enlargement of the parathyroid glands or a tumor may be to blame.
Low parathyroid hormone levels are indicative of a condition called hypoparathyroidism. The condition will eventually lead to hypocalcemia, or low calcium levels. Elevated phosphorus levels, or hyperphosphatemia, is also associated with hypoparathyroidism. Prolonged imbalance of calcium and phosphorus levels in the blood can lead to other health problems.
Hypoparathyroidism can be acquired or hereditary. Damage or removal of the parathyroid glands leads to acquired hypoparathyroidism. Usually acquired hypoparathyroidism is the result of surgery for cancer of the thyroid, throat or neck. Radiation therapy from cancer treatments can also damage the parathyroid gland. Hereditary hypoparathyroidism, on the other hand, is a result of malformed or missing parathyroid glands at birth.
Primary autoimmune hypoparathyroidism and secondary autoimmune disorders such as lupus are other factors in low parathyroid hormone levels. In primary and secondary autoimmune disorders the immune system views the parathyroid tissues as foreign bodies; as a result, the immune system will release antibodies to destroy the parathyroid tissues. Once the damage is done, the glands will cease to produce parathyroid hormone.
Magnesium is an essential element for the proper function of the parathyroid glands. Low levels of magnesium can impair the parathyroid, resulting in hypoparathyroidism. Usually, correcting low magnesium levels will normalize parathyroid hormone levels.
A condition called hyperparathyroidism is characterized by high parathyroid hormone levels. Hyperparathyroidism is classified as either primary or secondary, depending on the cause. Primary hyperparathyroidism can be due to enlargement of two or more parathyroid glands, a benign growth called an adenoma, or a cancerous tumor.
When another condition lowers calcium levels, secondary hyperparathyroidism occurs. Factors that may cause secondary hyperparathyroidism are severe deficiencies of calcium and vitamin D. Without the appropriate vitamin D levels, calcium may not be absorbed properly, resulting in a calcium deficiency. Not getting enough sunlight or not eating enough vitamin D enriched foods are just two of many factors responsible for a vitamin D deficiency.
Sometimes the cause of low calcium and vitamin D is kidney failure. Kidneys are tasked with converting vitamin D into a form the body can use. Reduced kidney function can cause usable vitamin D and consequently calcium to simultaneously drop.