Lower total 25-hydroxyvitamin D but no difference in calculated or measured free 25-hydroxyvitamin D serum levels in patients with primary hyperparathyroidism.

To evaluate the measured free 25-hydroxyvitamin D [25(OH)D] levels in patients with hyperparathyroidism (PHPT) and healthy controls. Eighty patients with PHPT(n = 40) and age and BMI matched controls (n = 40) were examined. Serum levels of total or free 25(OH)D, vitamin D binding protein (DBP), intact parathyroid hormone (iPTH) and calcium were measured. There was no significant difference in age (61.2 ± 11.9 vs 60.2 ± 7.0 years) and BMI (30.0 ± 6.1 vs 30.0 ± 2.2 kg/m2) between PHPT patients and healthy subjects. Levels of total 25(OH)D were about 20 % lower in PHPT patients (26.4 ± 7.7 ng/mL) compared to controls (31.0 ± 7.8 ng/mL, P < 0.05). There were no significant differences in calculated or measured free 25(OH)D levels between PHPT patients (4.9 ± 1.8 or 4.9 ± 1.6 pg/mL, respectively) and control subjects (5.1 ± 1.2 or 5.3 ± 1.6 pg/mL, respectively). Levels of free 25(OH)D were positively associated with levels of total 25(OH)D (r = 0.28, P < 0.05) but negatively correlated with iPTH and calcium levels (r=-0.22 and -0.23 respectively, P < 0.05). Serum total 25(OH)D levels were lower but the calculated or measured free 25(OH)D levels in patients with PHPT did not differ from healthy subjects. We suggest that total 25(OH)D levels may not reflect true vitamin D nutritional status in patients with PHPT.

Serum Klotho levels in primary hyperparathyroidism patients before and after parathyroidectomy.

PURPOSE: To investigate Klotho level and its association with biochemical indices of primary hyperparathyroidism (PHPT). METHODS: Fifty PHPT patients and fifty-two age- and body mass index-(BMI) matched healthy control subjects were recruited. In addition, twenty-five PHPT patients underwent parathyroidectomy (PTX) and had 4-month follow-up visits. Intact parathyroid hormone (iPTH), 25-hydroxyvitamin D [25(OH)D], calcium, albumin, corrected calcium, and Klotho levels were determined. RESULTS: There was no significant difference in age and BMI between PHPT subjects and controls (p > 0.05). PHPT patients had Klotho levels (15.4 ± 1.2 ng/mL) about 23% higher compared with those of the controls (11.9 ± 0.8 ng/mL), but this difference was not significant (p = 0.063). However, postmenopausal PHPT patients had 45% higher Klotho levels (17.6 ± 1.5 ng/ml) compared with postmenopausal controls (12.1 ± 0.9 ng/mL, p = 0.008). For postmenopausal subjects, Klotho levels had positive correlation with levels of iPTH (r = 0.25, p = 0.026) and corrected calcium (r = 0.34, p = 0.003), but negative correlation with 25(OH)D (r = -0.23, p = 0.042). After PTX, levels of iPTH and corrected calcium decreased and 25(OH)D levels increased to normal range (p < 0.001). However, there was no significant change in Klotho levels after a 4-month follow-up. CONCLUSIONS: Serum Klotho levels are higher in postmenopausal PHPT patients than in healthy postmenopausal control subjects. The etiology of elevated Klotho level and its clinical significance requires further investigation.

Comparison of Initial Clinical Presentations between Primary Hyperparathyroidism Patients from New Brunswick and Changsha.

PURPOSE: To compare the initial clinical features, laboratory values, and bone mineral density among patients with primary hyperparathyroidism (PHPT) in Changsha (China) and New Brunswick (USA). METHODS: In this retrospective study, we reviewed 169 PHPT patients who presented at Robert Wood Johnson University Hospital and 133 PHPT patients who presented at the Second Xiangya Hospital of Central South University in the same time period. The following characteristics were compared between the groups: age, gender, BMI, serum calcium, alkaline phosphatase (AKP), albumin, intact PTH (iPTH), 25-hydroxyvitamin D (25 (OH) D), fasting blood glucose levels, and bone mineral density (BMD). All these parameters were also compared according to gender and menopausal status. iPTH associations were also assessed along with several other parameters. RESULTS: PHPT patients from Changsha had higher serum calcium, iPTH, and AKP levels but lower 25 (OH) D levels than the patients from New Brunswick (p < 0.05). Patients in Changsha had lower T-scores and Z-scores in both the lumbar spine and hip regions than those in New Brunswick (p < 0.05). Patients in New Brunswick had lower percentages of parathyroid adenoma and kidney stones. Serum iPTH level was positively correlated with serum calcium and serum AKP levels in both Changsha and New Brunswick (p < 0.05). CONCLUSIONS: There are distinct biochemical and clinical differences between patients with PHPT in China and the United States. Our study revealed that Asian PHPT patients from Changsha presented more severe PHPT profiles, lower bone mineral density, and higher incidence of renal stones.