Effect of Supplementation with Vitamin D3 and Calcium on Quantitative Ultrasound of Bone in Elderly Institutionalized Women: A Longitudinal Study

Abstract:

Supplementation of elderly institutionalized women with vitamin D and calcium decreased hip fractures and increased hip bone mineral density. Quantitative ultrasound (QUS) measurements can be performed in nursing homes, and easily repeated for follow-up. However, the effect of the correction of vitamin D deficiency on QUS parameters is not known. Therefore, 248 institutionalized women aged 62–98 years were included in a 2-year open controlled study. They were randomized into a treated group (n = 124), receiving 440 IU of vitamin D₃ combined with 500 mg calcium (1250 mg calcium carbonate, Novartis) twice daily, and a control group (n = 124). One hundred and three women (42%), aged 84.5 ± 7.5 years, completed the study: 50 in the treated group, 53 in the controls. QUS of the calcaneus, which measures BUA (broadband ultrasound attenuation) and SOS (speed of sound), and biochemical analysis were performed before and after 1 and 2 years of treatment. Only the results of the women with a complete follow-up were taken into account. Both groups had low initial mean serum 25-hydroxyvitamin D levels (11.9 ± 1.2 and 11.7 ± 1.2 mg/l; normal range 6.4–40.2 mg/l) and normal mean serum parathyroid hormone (PTH) levels (43.1 ± 3.2 and 44.6 ± 3.5 ng/l; normal range 10–70 ng/l, normal mean 31.8 ± 2.3 ng/l). The treatment led to a correction of the metabolic disturbances, with an increase in 25-hydroxyvitamin D by 123% (p50.01) and a decrease in PTH by 18% (p50.05) and of alkaline phosphatase by 15% (p50.01). In the controls there was a worsening of the hypovitaminosis D, with a decrease of 25-hydroxyvitamin D by 51% (p50.01) and an increase in PTH by 51% (p50.01), while the serum calcium level decreased by only 2% (p5 0.01). After 2 years of treatment BUA increased significantly by 1.6% in the treated group (p50.05), and decreased by 2.3% in the controls (p50.01). Therefore, the difference in BUA between the treated subjects and the controls (3.9%) was significant after 2 years (p50.01). However, SOS decreased by the same amount in both groups (approximately 0.5%). In conclusion, BUA, but not SOS, reflected the positive effect on bone of supplementation with calcium and vitamin D₃ in a population of elderly institutionalized women.