W. J. Maclennan

Vitamin D supplements and 25-hydroxy vitamin D concentrations in the elderly.

Serial 25-hydroxy vitamin D (25-OHD) concentrations were measured in long-stay geriatric patients treated with vitamin D. Comparison between a treatment and a control group showed that a daily dose of 500 IU vitamin D produced a significant increase in 25-OHD levels by two months. The supplement had a striking effect when the initial 25-OHD level was low and very little effect when it was high. 25-OHD levels in subjects on 2000 IU vitamin D daily were only marginally higher than those in subjects on 500 IU. A dose of 500 IU vitamin D daily should therefore produce adequate blood 25-OHD concentrations in most old people, and probably prevent most cases of osteomalacia in the elderly--though a large-scale study is needed to confirm this.

Diet, sunlight, and 25-hydroxy vitamin D.

We believe that the most dramatic effect of preoperative and postoperative loHCC in primary hyperparathyroidism is in the management of those few patients with really severe bone disease whose postoperative management in previous times remained stormy over several months. We have been accustomed to seeing about one such patient per year at Glasgow Royal Infirmary and believe that at least five of our 15 patients mentioned above would have fallen in this category (all had serum alkaline phosphatase and parathyroid hormone levels (where measured) some 10 times higher than the upper limits of normal). Such patients may not be encountered in Birmingham but still unfortunately turn up in Glasgow. A body of evidence now exists3-5 to suggest that vitamin D deficiency may play a role in the genesis of the bone disease in these severe cases. On the one hand the vitamin D deficiency may cause an increase in parathyroid hormone secretion, while on the other hand the primary hyperparathyroidism may cause an increased requirement for vitamin D, possibly through the increased renal turnover of 25-hydroxy vitamin D3. On this basis one might anticipate some amelioration of the clinical problem by giving IaHCC before operation, and in a few cases we have indeed demonstrated some reduction in the serum parathyroid hormone level. In addition, the prophylaxis of paraesthesiae and tetany, even in the less severe cases, seems preferable to awaiting their postoperative appearance, and preoperative administration of 1oxHCC for three or four days, in addition to continuing it postoperatively for a similar period, usually achieves this aim as well as probably contributing to bone healing. Our present treatment schedule for 1 acHCC administration in primary hyperparathyroidism varies with the severity of the bone disease-I or 2 [eg daily for five to 10 days preoperatively followed by 1 or 2 ,ug daily for five to 50 days postoperatively.