PTH and vitamin D deficiency: Azab et al found similar percentages for secondary hyperparathyroidism (33%).[39] Hypocalcemia was mostly associated with severe vitamin D deficiency, while hypercalcemia was more prevalent in people with sufficient and possibly harmful levels of Vitamin D. High PTH was seen in severe deficiency, deficiency and vitamin D insufficiency, but also in the sufficiency group in 36% of assessments.