Vitamin D in parathyroid disease.

In June 2008 Dr Norman gave a lecture to the Endocrine Society's Annual Meeting in San Francisco, CA on Vitamin D in parathyroid disease. Here is an abstract of this talk; the journal article will be published later in 2008. Print this and take it to your doctor who put you on Vitamin-D. Most endocrinologists know this already, but many do not:
Vitamin D -25 is suppressed and Vitamin D-1-25 is increased in patients with primary hyperparathyroidism in linear fashion as calcium levels increase, returning to normal within weeks of tumor removal. A protective mechanism is in play.
Overview: Vitamin D-25 is converted to Vitamin D-1-25 in patients with primary HPT in a linear fashion as calcium levels increase. Thus the vast majority of patients with primary HPT will have low Vit D-25 that normalizes by itself in most patients within several months.
Objective: Vitamin D-25 is often measured in patients with apparent primary HPT to rule out a possible secondary cause. This study was undertaken to examine if a relationship exists between Vit-D levels and parathyroid pathology in patients with elevated calcium levels.
Methods: A prospective, single institution study measured preoperative Vitamin D (25OH and 1-25OH) in 1,587 patients undergoing surgery for sporadic primary hyperparathyroidism (PHPT) over a 1-year period. All patients underwent curative parathyroidectomy with pathology noted. Patients were put on nominal doses of Vit-D postop contained within supplemental calcium tablets (Citracal+D; 250 IU cholecalciferol daily) for two months; none took additional Vit-D. Blood levels were measured at 1 and 2 months post-op.
Results: All patients had primary HPT with high serum calcium and PTH preop that normalized at all postop measures indicating cure. The average preop Vit-D25 was 25.8+10 ng/ml (range 4-65). 1039 patients (67%) had Vit-D25 levels below 30 ng/ml preop, while 594 patients (38%) had levels below 20 ng/ml preop (mean 14.6, range 4-19), No patient had high Vit-D25 preop. Vit-D25 levels decreased linearly as calcium levels increased such that 71% of those with levels above 12 mg/dl had Vit-D25 <20 (p<0.01, R=0.91).The levels of Vit-D1-25 were low in 0%, normal in 58.5%, and high in 41.5% (mean 56.2 + 14)(p<0.01). The findings at surgery were identical (p=0.98) for those with low vs. normal Vit-D25 (single adenoma=92%, double adenoma=6%, 4-gland hyperplasia=3%). 82% of patients with low preop Vit-D25 had increased levels at 1 month postop (mean 41.4+12, range 17-63, p<0.005), increasing to 91% at 2 months. All patients with normal Vit-D25 preop remained normal postop. 68% showed decreased Vit-D1-25 into the normal range (p<0.001) within 1 month of surgery.
Conclusion: Vit-D25 levels decrease in a linear fashion as calcium levels rise in patients with primary HPT. Overall, 38% will have Vit-D25 levels less than 20 ng/ml, increasing to 71% of those with calcium levels above 12mg/dl. Vit-D1-25 shows the opposite pattern suggesting a protective mechanism. The pathology found at surgery is identical in PHPT patients with low versus normal Vit-D25 indicating no causal relationship. Low Vit-D25 should not be interpreted as signaling secondary HPT in patients with elevated calcium levels. The vast majority of patients will normalize their low Vit-D25 and high Vit-D1-25 levels within 2 months of tumor removal.

Blogger comment:
Of vitamin D 25 is low and calcium is below normal or not high supplement with vitamin D. If vitamin D is low or normal and calcium is high treat for hyperparathyroidism and do not give a trial of vitamin D like in the old days the only thing will happen is more hypercalcemia and renal stones.