Effects of calcium and vitamin D supplementation on hip bone mineral density and calcium-related analytes in elderly ambulatory Australian women: a five-year randomized controlled trial.
What this study found
Overall, adding vitamin D to calcium produced the most durable benefit, with no bone loss at the hip over 5 years and evidence of reduced bone turnover. Hip bone mineral density was maintained versus control at year 1 in both the calcium group (1.5 Ϯ 0.5%, P ϭ 0.007) and the calcium plus vitamin D group (1.2 Ϯ 0.6%, P ϭ 0.04), but only the calcium plus vitamin D group retained benefit at years 3 and 5 (2.8 Ϯ 1.1%, P ϭ 0.01; 2.2 Ϯ 1.1%, P ϭ 0.05). The calcium plus vitamin D group also had lower alkaline phosphatase at year 1, 3, and 5 (11.3 Ϯ 2.9%, P Ͻ 0.001; 8.7 Ϯ 3.9%, P ϭ 0.03; 11.3 Ϯ…
- Study & population
- Five-year randomized controlled trial in community-dwelling ambulant women aged 70 to 80 years in Perth, Western Australia, who were not receiving bone-active medications.
- Intervention
- Active supplementation consisted of calcium carbonate 600 mg twice daily with food for 5 years.
- Key limitation
- Arm sizes were modest (Ca N = 40, CaD N = 39, control N = 41), which limits precision and power for subgroup and biomarker analyses.
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Open PDFOriginal abstract
CONTEXT Effects of long-term calcium, with or without vitamin D, on hip bone mineral density (BMD) and bone turnover in sunny climates have not been reported. OBJECTIVE The aim was to evaluate the effect of vitamin D added to calcium supplementation on hip dual-energy x-ray absorptiometry BMD and calcium-related analytes. DESIGN, SETTING, AND PARTICIPANTS The study was a 5-yr randomized, controlled, double-blind trial of 120 community-dwelling women aged 70-80 yr. INTERVENTIONS The interventions were 1200 mg/d calcium with placebo vitamin D (Ca group) or with 1000 IU/d vitamin D2 (CaD group), or double placebo (control). MAIN OUTCOME MEASURES Hip BMD, plasma 25-hydroxyvitamin D, biomarkers of bone turnover, PTH, and intestinal calcium absorption were measured. RESULTS Hip BMD was preserved in CaD (-0.17%) and Ca (0.19%) groups but not controls (-1.27%) at yr 1 and maintained in the CaD group only at yr 3 and 5. The beneficial effects were mainly in those with baseline 25-hydroxyvitamin D levels below the median (68 nmol/liter). At yr 1, compared with controls, the Ca and CaD groups had 6.8 and 11.3% lower plasma alkaline phosphatase, respectively (P<or=0.02), and 28.7 and 34.5% lower urinary deoxypyridinoline to creatinine ratio, respectively (P<or=0.05). At 5 yr, this suppression was maintained only in the CaD group. CaD reduced PTH at 3 and 5 yr cf. controls (27.8 and 31.3%, P<or=0.005) in those with baseline PTH levels above the median (3.6 pmol/liter). Therapy did not affect intestinal calcium absorption at high carrier loads. CONCLUSIONS Addition of vitamin D to calcium has long-term beneficial effects on bone density in elderly women living in a sunny climate, probably mediated by a long-term reduction in bone turnover rate.