Cholecalciferol is almost twice as potent as ergocalciferol in increasing serum 25(OH)D, when administered either by mouth or im. 25(OH)D plays a role in modulating serum PTH.

Studies on skeletal involvement in patients with diabetes mellitus have generated conflicting results, largely because of the pathogenetic complexity of the condition. Several mechanisms may contribute to skeletal damage, including the increased urinary excretion coupled with the lower intestinal absorption of calcium, the inappropriate homeostatic response in terms of parathyroid hormone secretion, and also the complex alteration of vitamin D regulation. Decreased or increased insulin and IGF-1 concentrations and the effects of the accumulation of glycation endproducts on the bone tissue could also play a role. A possible genetic predisposition is also currently under investigation. Finally, the role of fat tissue in type 1 and type 2 diabetes and that of diabetic complications also deserve note. As far as bone mass is concerned, in adult patients with type 1 diabetes a moderately reduced bone mineral density has been shown in both axial and appendicular skeleton. On the contrary, patients with type 2 diabetes seem to have higher bone mineral density in respect to healthy control subjects, especially when overweight women are considered. No clear relationship between bone mass measurements and biochemical parameters of mineral metabolism has been shown in the different types of diabetes. Cohort studies recently carried out on large samples indicate that diabetic patients (with both type 1 and type 2 disease) have a higher risk for fracture, in particular for hip fracture, the most dangerous osteoporotic complication. This seems to be dependent both on qualitative and quantitative alterations of the bone, as well as on extra-skeletal factors due to the neuropathic and microangiopathic complications of the disease.

Health-related quality of life (HRQOL) in postmenopausal women with osteoporosis has hitherto been mainly assessed in patients with clinically recognized vertebral fractures. Our study aimed to investigate the QOL perception in 361 asymptomatic ambulant postmenopausal women who came to our center for an osteoporosis screening program planned with their general practitioners. The Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO) was administered to all subjects. The participants underwent bone mineral density (BMD) measurements by DXA of either the lumbar spine and/or the femoral neck, as well as X-ray examination of the thoracolumbar spine to identify subclinical vertebral fractures. According to the WHO definition, where subjects are subdivided by BMD values into three groups (women with normal BMD, osteopenia, and osteoporosis), a significant difference was found only for the domains which explore general health perception (p<0.01 by ANOVA) and mental function (p<0.001 by ANOVA). When we segregated both osteopenic and osteoporotic women according to whether or not they had vertebral fractures, a significant difference was found only in osteoporotic patients for domains which explore physical function (p<0.001), social function (p<0.001), general health perception (p<0.02), and total QUALEFFO score (p<0.01). Stepwise multiple logistic regression analysis of the whole sample showed that both vertebral fractures and a low femoral BMD impairs QOL perception, while age did not exert a significant influence. ROC curves analysis demonstrated a low discriminating capacity of individual domains and total QUALEFFO score for both vertebral deformities and BMD categorization. Our results showed that QUALEFFO is not able to discriminate between patients with or without subclinical vertebral fractures. However, some aspects of QOL appear to be impaired in patients with subclinical vertebral fractures or reduced BMD.

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The neurofibromatosis type 1 (NF1) is characterized by specific cutaneous features (neurofibromas, "café-au-lait" spots of the skin) and alterations of several tissue (nervous, vascular) and bone deformities, such as scoliosis, congenital pseudoarthrosis and bone dysplasia of tibia. Moreover, several studies have shown systemic involvement of bone tissue in NF1 patients, leading to reduced bone mass. The aim of our study was to evaluate some bone mineral metabolism parameters before and after calcium and vitamin D supplementation in NF1 patients. We evaluated in 70 NF1 consecutive patients the mineral metabolism and bone mineral density compared with 40 normal subjects. We showed bone alterations in 35% of patients and the increase of bone formation markers, such as bone isoenzyme of alkaline phosphatase (41.2 ± 15.5 vs. 25.6 ± 8.7 UI; P < 0.05, respectively) and osteocalcin (18.1 ± 5.6 vs. 7.6 ± 1.9 ng/ml; P < 0.05) and reduction of circulating levels of (25OH)-vitamin D (21.8 ± 12.3 ng/ml) with an high percentage of hypovitaminosys D (>60%). Moreover, we revealed a significant reduction of bone mass density at spine (L1-L4) (0.935 ± 0.13 vs. 1.110 ± 0.17 g/cm(2); P < 0.001) and femoral neck side (0.765 ± 0.09 vs. 0.839 ± 0.12 g/cm(2); P < 0.02), with high prevalence of osteopenia (44%) and osteoporosis (18%). After 12 months of calcium (1,200 mg/die) and cholecalciferol (800 UI/die) supplementation, we found a significant increase of (25) OH-vitamin D level (21.8 ± 12.3 vs. 35 ± 13 ng/ml; P < 0.01), without changes in bone mass density. In conclusion, NF1 patients may present a mineral bone involvement, with vitamin D deficiency; calcium and vitamin D supplementation is necessary to restore these bone mineral metabolic alterations.