Effets sur la densité minérale osseuse d’une supplémentation vitamino-calcique chez la femme âgée présentant une insuffisance en vitamine D

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Objectives. – Calcium and vitamin D deficiency is common in older individuals, particularly those who live in nursing homes, and increases the risk of osteoporosis and fractures. Methods. – We conducted a randomized double-blind placebo-controlled study of combined supplementation with 500 mg of elemental calcium, as carbonate, and 400IU of vitamin D bid for 12 months in women older than 65 years of age with vitamin D deficiency defined as serum 25(OH)D concentrations ≤ 12 ng/ml. Results. – Mean patient age was 75 ± 7 years and median daily dietary intakes of calcium and vitamin D were 697 mg and 66.8 IU in the supplemented group ( n = 95) and 671 mg and 61.8IU in the placebo group ( n = 97). The median serum 25(OH)D level was 7.0 ng/ml in both groups, and the medial intact parathyroid hormone (PTHi) levels were 49 pg/ml and 48 pg/ml in the supplemented and placebo groups, respectively. The median increase in serum 25(OH)D was 22.0 ng/ml in the supplemented group and 4 ng/ml in the placebo group ( p < 0.0001) and the median PTHi decrease was 17 pg/ml and 5 pg/ml, respectively ( p < 0.0001). The median bone mineral density increase was significantly greater in the supplemented group than in the placebo group: + 2.98% vs. – 0.21% at L2-L4 ( p = 0.0009), + 1.19% and – 0.83% at the femoral neck ( p = 0.015), + 0.86% and – 0.56% at the trochanter ( p = 0.015), and + 0.99% and + 0.11% for the whole body ( p = 0.01). Similarly, the median decrease in the main bone markers was significantly greater in the treated group than in the placebo group: – 1.35 μg/l vs. + 0.50 μg/l for bone alkaline phosphatase ( p = 0.008), – 16.6 nmol/mmol creatinine vs. – 2.3 nmol/mmol creatinine for urinary type I amino-terminal telopeptide ( p = 0.001), and – 896 pmol/l vs. – 201 pmol/l for serum type I carboxy-terminal telopeptide ( p = 0.003). We found no significant differences between the two groups for serum calcium, although urinary calcium excretion changed more in the supplemented group than in the placebo group. In conclusion, bone mass in older women with vitamin D deficiency increases significantly at the lumbar spine, femur, trochanter, and whole body after calcium and vitamin D supplementation for 1 year, and concomitantly bone markers improved as vitamin D levels returned to normal.