Although vitamin D levels in the obese individuals were low, few displayed overt signs of secondary HPT. The CiCa clamping implied a disturbance in the calcium homeostasis comparable to early renal insufficiency, with a left-shifted Ca-PTH curve and a lower set point compared with the normal population.

A history of parathyroid adenoma should be viewed as a risk for preeclampsia.

Patients with GD demonstrate dysregulation of the calcium homeostasis by several parameters. GD patients have lower postoperative serum calcium compared with patients with MNG, lower calcium/PTH set point, and a significantly increased release of PTH to hypocalcemic stimulus compared with controls. The CiCa clamp response in GD patients with normal 25-hydroxyvitamin D3 levels mimics that of obese patients in which vitamin D insufficiency has been proposed as an underlying cause.