The effect of a combined oral calcium and vitamin D supplement for treating mild to moderate vitamin D deficiency in postmenopausal women

Objective

To evaluate the efficacy of a combined calcium and vitamin D (Ca-D3) supplement for vitamin D deficiency in a small group of postmenopausal women.

Methods

A prospective open label 3 month-study.

Participants

23 postmenopausal women (mean age 61.2 yrs) with vitamin D deficiency were given a combined oral Ca-D3 supplement called “Osteoblast”. The supplement comprises 500 mg elemental calcium and 500 IU of cholecalciferol. The dosing regimen comprised a loading dose of 1000 IU of cholecalciferol per day for one month (two tablets) and thereafter a maintenance dose of 500 IU of cholecalciferol per day for 2 months (one tablet).

Outcome measure

Serum was collected for calcium, 25 hydroxyvitamin D3 (25OHD3), and PTH measurements, as well as early morning 2-hour urine calcium/creatinine excretion index (Uca/creat). Specimens were collected at baseline and after 3 months of therapy. Data are reported as mean ± 1 standard error and 95% confidence intervals.

Results

Data was available for the 21 subjects who completed the study. Two subjects (9%) withdrew because of gastrointestinal intolerance. There were 3 subjects with moderate (12.5–24 nmol/L) and 18 with mild (25–49 nmol/L) vitamin D deficiency. Ten subjects (48%) had secondary hyperparathyroidism. Following the oral Ca-D3 combination, serum 25OHD3 levels normalised in all subjects with 18 (86%) subjects achieving values of greater than 70 nmol/L. Serum 25OHD3 levels increased from 36 (31–41) to 91 (79–102) nmol/L (p = 0.0001), increasing by an average of 152% over the 3-month period. There was a corresponding 38% decrease in serum PTH concentrations at 3 months (5.1 + 0.6 pmol/L), compared with baseline (8.0 + 1 pmol/L) (p = 0.001). No subject developed hypercalcemia, but an elevated Uca/creat excretion index occurred in one subjects.

Conclusions

A combined oral Ca-D3 product (Osteoblast) is effective for treating vitamin D deficiency and is adequately tolerated.