Secondary hyperparathyroidism (SHPT) does not initiate as a primary dysfunction of parathyroid glands resulting from an intrinsic defect or disease but is the physiologic response of parathyroids to metabolic changes elsewhere in the body occurring over time. SHPT is a manifestation of a chronic condition that classically occurs from chronic kidney disease. In fact, given the relatively recent transition of populations from outside (agrarian) to indoor (industrial, information technology, and so forth) employment and a consequent reduction in sun exposure, combined with diets of highly processed food, vitamin D and calcium deficiencies are now the leading causes of SHPT.