Vitamin D status among patients with hip fracture and elderly control subjects in Yekaterinburg, Russia

Purpose Vitamin D deficiency leads to secondary hyperparathyroidism and osteomalacia, and both conditions are associated with fractures, the most severe being hip fracture. The serum 25-hydroxyvitamin D level depends on latitude and season. Yekaterinburg is situated at a high latitude and the duration of winter is about 5 months. Methods In this study, the serum 25(OH)D and PTH concentrations, and the prevalence of hypovitaminosis D in elderly people, inhabitants of Yekaterinburg, were investigated. The study was performed on 63 people with hip fracture (mean age, 68.8 years) and 97 independently living elderly people (mean age, 70.2 years). Results Serum 25(OH)D (mean±SD) in the hip fracture group was 22.4±11.4 nmol/L, significantly lower than in control group, which was 28.1±10.1 nmol/L. The percentage of patients with severe hypovitaminosis D (<25 nmol/L) in the hip fracture group was 65%, compared to 47% in the control group (p<0.05). The prevalence of hypovitaminosis D among hip fracture patients, as well as among independently living elderly people in Yekaterinburg, was high. Conclusion Supplementation of vitamin D in elderly people with and without fracture might prevent secondary hyperparathyroidism, osteomalacia and fractures.     

Hypovitaminosis D in patients with osteoporotic hip fractures

BackgroundInadequate serum vitamin D levels are associated with secondary hyperparathyroidism, increased bone turnover, bone loss and increased fracture risk. Vitamin D is well recognized to be suboptimal in older patients when compared to age-matched controls. There are no published studies on the prevalence of hypovitaminosis D in Indian population with fragility fractures around the hip associated with osteoporosis and comminution at the fracture site.AimTo investigate the prevalence of hypovitaminosis D in patients admitted with osteoporotic hip fractures and associated fracture site comminution in a South Indian Institute.Material & MethodsA prospective cross sectional study was conducted on 100 patients admitted with osteoporotic hip fracture. Measurement of serum 25-hydroxy vitamin D was done and the same was correlated with the degree of osteoporosis using Singh’s index and fracture site comminution.ResultsOut of 100 patients studied, 92% had hypovitaminosis D with mean vitamin D level of 16.08 ± 5.95 ng/dl (65% vitamin D deficiency with mean 13.16 ± 4.24 ng/dl and 27% vitamin D insufficiency with mean 23.11 ± 2.62 ng/dl) and 94% had osteoporosis with Singh’s index grade 3 or less. Out of the 36 patients with fracture site comminution 34 patients (94%) had hypovitaminosis D and 33 patients (91.6%) had osteoporosis. Statistical significance was established for all the variables.ConclusionSignificant association was found between hypovitaminosis D, osteoporosis and fracture site comminution. High prevalence of hypovitaminosis D in patients presenting with hip fractures and fracture site comminution implicates the necessity for proper evaluation and effective supplementation of vitamin D in elderly patients along with anti-osteoporotic regimens for effective prevention and appropriate management of osteoporotic hip fractures.     

High prevalence of vitamin D insufficiency in a United Kingdom urban morbidly obese population: Implications for testing and treatment

BackgroundCurrent recommendations suggest universal screening of vitamin D status before bariatric surgery to identify individuals at risk for postoperative deficiency. However little is known about the magnitude or severity of vitamin D insufficiency in the morbidly obese population awaiting bariatric surgery in the United Kingdom. The purpose of this prospective observational study was to assess the prevalence and determinants of vitamin D insufficiency in an urban multiethnic U.K. population awaiting bariatric surgery.MethodsConsecutive patients attending a morbid obesity service were comprehensively assessed using a recognized obesity staging tool. Data collected included 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), corrected calcium (Ca²⁺), body mass index (BMI), and the presence and severity of obesity associated co-morbidities, including type 2 diabetes (T2 DM), cardiovascular disease (CVD), depression, obstructive sleep apnea (OSA), and functional limitation.ResultsOf the 118 patients assessed, 79% were female, and 21% were male, with BMI of 52.6±9.4 kg/m² (mean±standard deviation) and mean age of 44±11 years. Twenty-four percent had T2 DM, 28% CVD, 31% OSA, and 21% depression. Vitamin D insufficiency was found in 90% of the population, with a median serum 25(OH)D of 8.8 ng/mL. Secondary hyperparathyroidism was present in 43% of those with vitamin D insufficiency. Risk was not influenced by ethnicity, age, or gender. However severe functional limitation was associated with lower vitamin D status.ConclusionRegardless of ethnicity, vitamin D insufficiency appears to be typical among this clinic population; therefore, routine vitamin D supplementation is suggested for all individuals awaiting bariatric surgery rather than testing vitamin D status in an attempt to identify high-risk individuals.     

Comparison of 25-OH vitamin D levels between children with upper and those with lower extremity fractures: A prospective case-control study

Objective:The aims of this study were (1) to compare 25-OH vitamin D levels between children with upper and those with lower extremity fractures and (2) to determine whether 25-OH D insufficiency prevalence is increased compared to healthy controls.Methods:This is a prospective case–control study for 12 months. The study was conducted with children aged 5-18 years, including 60 children with non-displaced, impaction type upper extremity and lower extremity fractures resulted from low-energy trauma. In addition, 60 healthy children were included as controls. In all participants, risk factors for low bone mineral density were assessed and serum 25(OH)D levels were measured. Vitamin D levels were compared among groups.Results:Vitamin D deficiency (25-OH D <20) was 14.8 times (OR= 95% CI= 5.61 - 39.8) and 2.9 times (OR= 95% CI= 1.46-5.75) higher in patients with upper and lower extremity fractures, respectively. In the upper extremity fracture group, serum 25-OH D level was considered deficient (25-OH D level = <20 ng/mL) in 91.6% (55/60). In comparison, it was considered as insufficient (serum 25-OH D level = 20-30 ng/mL in 8.3% (5/60) of the patients. In the lower extremity fracture group, serum 25(OH)D level was considered as deficient in 75.0% (45/60), while it was considered as insufficient in 25.0% (15/60) of the patients. In the control group, serum 25-OH D level was considered deficient in 10.0% (6/60), while it was considered insufficient in 61.6% (37/60) of subjects. The 25-OH D deficiency and insufficiency were more common in the whole fracture group (upper plus lower extremity fracture groups) when compared to healthy controls.Conclusion:This study has shown that hypovitaminosis D is associated with an increased risk for fracture in the pediatric population, and the fracture risk is higher in upper extremity fractures than in lower extremity fractures. In children with fractures, routine vitamin D evaluation should be considered.Level of Evidence: Level III, Diagnostic Study     

Vitamin D Insufficiency in Internal Medicine Residents

Medical residents may be vulnerable to low vitamin D status because of long work hours and lack of sun exposure. We conducted a prospective cohort study to measure serum 25-hydroxyvitamin D concentrations among internal medicine residents, document seasonal variation in vitamin D status, and assess risk factors for inadequate vitamin D stores. Dietary intake of calcium and vitamin D, lifestyle characteristics, and serum concentrations of 25(OH)-vitamin D and intact parathyroid hormone (iPTH) were measured in 35 resident volunteers before and after the winter season. A total of 63–69% of medical residents consumed <400 IU/day of vitamin D; 61–67% consumed <1000 mg/day of calcium. Twenty-five (74%) had lower serum 25(OH)-vitamin D concentrations and 23 (68%) had higher serum iPTH in the spring than in the fall. Nine (26%) residents had serum concentrations of 25(OH)-vitamin D of <20 ng/mL in the fall; and sixteen (47%) in the spring. Seven residents (20%) had serum concentrations of 25(OH)-vitamin D of <20 ng/mL at both time-periods; Eighteen residents (51.4%) had 25(OH)-vitamin D levels of <20 ng/mL for at least one of the time-periods. Medical residents are at risk for hypovitaminosis D, particularly during the winter months and should be aware of the need to supplement their vitamin D stores. Insufficient vitamin D status and inadequate vitamin D intake may have long-term implications for bone health in these individuals. Increased educational efforts to promote healthy dietary and lifestyle choices that allow attainment and maintenance of skeletal health are appropriate in this population.Presented in part at the National Meeting of the Society of General Internal Medicine, (Vancouver, BC, May, 2003).     

Prevalence of vitamin D depletion among subjects seeking advice on osteoporosis: a five-year cross-sectional study with public health implications

Summary We assessed vitamin D nutritional status in unselected consecutive patients seeking advice on osteoporosis. The prevalence of vitamin D depletion ranged from 15–72% depending upon the cut-off levels used for serum 25-hydroxyvitamin D, and the prevalence did not change over the 5 years of the study. Introduction Vitamin D depletion is a significant public health problem and has been studied in different populations using different cut-off levels, but the optimal level is yet to be established. Methods In a cross-sectional study of 2924 patients seen for osteoporosis advice we determined the prevalence of vitamin D depletion, as assessed by 25-hydroxyvitamin D (25-OHD), using three different cut-off levels stratified by gender, race and the year of the study over 5 years. Results Mean age was 68.3 ± 10.0 years; 90% women and 88% white. Mean 25-OHD level was 24.6 ± 10 ng/ml and mean PTH was 48.4 ± 32 pg/ml. The prevalence of vitamin D depletion was 15% with a cut-off level of <15 ng/ml, and rose to 32% and 72% with cut-off levels <20 ng/ml and <30 ng/ml, respectively. The prevalence was higher in men and blacks and remained constant over 5 years, regardless of the cut-off level. The expected inverse relationship between 25-OHD and PTH was observed irrespective of gender or ethnicity. Conclusions The prevalence of vitamin D depletion in patients seeking advice for osteoporosis is high and did not change over the 5 years of the study.     

Vitamin D for skeletal and non-skeletal health: What we should know

Vitamin D plays an essential role in regulating calcium and phosphate metabolism and maintaining a healthy mineralized skeleton. Humans obtain vitamin D from sunlight exposure, dietary foods and supplements. There are two forms of vitamin D: vitamin D₃ and vitamin D₂. Vitamin D₃ is synthesized endogenously in the skin and found naturally in oily fish and cod liver oil. Vitamin D₂ is synthesized from ergosterol and found in yeast and mushrooms. Once vitamin D enters the circulation it is converted by 25-hydroxylase in the liver to 25-hydroxyvitamin D [25(OH)D], which is further converted by the 25-hydroxyvitamin D-1α-hydroxylase in the kidneys to the active form, 1,25-dihydroxyvitamin D [1,25(OH)₂D]. 1,25(OH)₂D binds to its nuclear vitamin D receptor to exert its physiologic functions. These functions include: promotion of intestinal calcium and phosphate absorption, renal tubular calcium reabsorption, and calcium mobilization from bone. The Endocrine Society's Clinical Practice Guideline defines vitamin D deficiency, insufficiency, and sufficiency as serum concentrations of 25(OH)D of <20 ng/mL, 21–29 ng/mL, and 30–100 ng/mL, respectively. Vitamin D deficiency is a major global public health problem in all age groups. It is estimated that 1 billion people worldwide have vitamin D deficiency or insufficiency. This pandemic of vitamin D deficiency and insufficiency is attributed to a modern lifestyle and environmental factors that restrict sunlight exposure, which is essential for endogenous synthesis of vitamin D in the skin. Vitamin D deficiency is the most common cause of rickets and osteomalacia, and can exacerbate osteoporosis. It is also associated with chronic musculoskeletal pain, muscle weakness, and an increased risk of falling. In addition, several observational studies observed the association between robust levels of serum 25(OH)D in the range of 40–60 ng/mL with decreased mortality and risk of development of several types of chronic diseases. Therefore, vitamin D-deficient patients should be treated with vitamin D₂ or vitamin D₃ supplementation to achieve an optimal level of serum 25(OH)D. Screening of vitamin D deficiency by measuring serum 25(OH)D is recommended in individuals at risk such as patients with diseases affecting vitamin D metabolism and absorption, osteoporosis, and older adults with a history of falls or nontraumatic fracture. It is important to know if a laboratory assay measures total 25(OH)D or only 25(OH)D₃. Using assays that measure only 25(OH)D₃ could underestimate total levels of 25(OH)D and may mislead physicians who treat patients with vitamin D₂ supplementation.     

血清25-羟维生素D浓度检测对膝骨关节炎临床诊疗意义

目的：研究与探讨血清25－羟基维生素D浓度检测对膝骨关节炎临床诊疗的指导意义。方法随机抽取2011年6月至2011年10月以及2012年6月至2012年10月期间骨科门诊主诉有膝关节疼痛患者1174名,采用罗氏诊断试剂盒检测患者血清中的25－羟基维生素D浓度。结果1174例患者平均年龄（53．61±15．10）岁,血清25－羟维生素D浓度平均值为15．55 ng／ml,维生素D缺乏者（＜20 ng／ml）占48．12％（524例）,其中严重缺乏者（＜10 ng／ml）占26．35％（287例）。2011年测得血清25－羟基维生素D浓度平均值为13．27 ng／ml（参考值为11．10～42．90 ng／ml）;2012年测得血清25－羟基维生素D浓度平均值为22．53 ng／ml（参考值为20～32 ng／ml）。结论血清25－羟基维生素D浓度检测在膝骨关节炎诊疗中具有重要指导意义。本次研究中应用的罗氏诊断血清25－羟维生素D3检测试剂参考值有波动,直接导致2011年度与2012年度同期所检测出的患者血清25－羟基维生素D浓度存在一定的偏差。     

Vitamin D status in pediatric osteoarticular tuberculosis

Background

Tubercular patients, in general, have been demonstrated with lower serum levels of vitamin D, but the levels in osteoarticular tuberculosis (TB) in children are largely unknown. We aimed to determine serum vitamin D status in pediatric cases with osteoarticular TB.

Methods

The values of serum vitamin D were estimated in 100 children with osteoarticular TB. The patients were divided into three groups based on gender, age, and site to assess variations of vitamin D levels in pediatric osteoarticular TB.

Results

Hypovitaminosis D was associated with active osteoarticular TB in children. The mean vitamin D levels were 42.165 nmol/L. There were no statistical difference between mean vitamin D levels in boys and girls (p value = 0.6143); age groups <5 and 5–12 years (p value = 0.3857); or spinal and non-spinal osteoarticular groups (p value = 0.8350).

Conclusions

Active osteoarticular TB in children was also associated with hypovitaminosis D. The correlation between hypovitaminosis D and osteoarticular TB appears to be more disease specific rather than host specific.     

Serum 25-OHD insufficiency as a risk factor for hip fracture

The aging population and an increasing number of hip fractures worldwide have made prevention of hip fractures a matter of importance. The prevalence of hypovitaminosis D in patients with acute hip fracture has been reported widely in recent years, and the vitamin D nutritional status in such reports is usually evaluated based on serum 25-hydroxyvitamin D (25-OHD). The aim of this article is to review the relationship of serum 25-OHD and osteoporotic fracture and the prevalence of 25-OHD insufficiency in patients with hip fracture, including assessment of nutritional status, oral status, activity, and dementia. We conclude that the serum 25-OHD level may be a useful index for risk of hip fracture in elderly people.     

High Prevalence of Hypovitaminosis D among Free-Living Postmenopausal Women Referred to an Osteoporosis Outpatient Clinic in Northern Italy for Initial Screening

To establish the prevalence of hypovitaminosis D among free-living postmenopausal women referred to an osteoporosis outpatient clinic in Northern Italy, we evaluated 25-hydroxyvitamin D (25(OH)D) levels in 570 postmenopausal women who had been consecutively referred to our clinic in the 12 months beginning October 1995. Parathyroid hormone (PTH), serum calcium (Ca), creatinine (Cr) and osteocalcin (OC), urinary calcium (Ca24h) and creatinine (Cr24h), and the bone mineral density of the lumbar spine (LBMD) and femur (FBMD) were also measured. 1,25-Dihydroxyvitamin D (1,25(OH)₂D) concentrations were measured in 23 women. All women had normal electrolyte serum concentrations and kidney function. Mean ± SD 25(OH)D concentration was 18.3 ± 8.3 ng/ml. A significant (p<0.001) seasonal variation was seen for both 25(OH)D and PTH. Women were divided into two groups based on their vitamin D status: low vitamin D status (25(OH)D <12 ng/ml, n= 161, 28%) and normal vitamin D status (25(OH)D ≥12 ng/ml, n= 409, 72%). Hypovitaminosis D was found in 38.5% of all the women in the time period December–May and in 12.5% in the other half-year; among women >70 years old 51% had hypovitaminosis D in the time period December–May and 17% in the other half-year. PTH was significantly (p<0.05) increased, and Ca24h, OC and FBMD significantly (p<0.05) decreased in women with hypovitaminosis D. 1,25(OH)₂D positively correlated with 25(OH)D (p<0.0001), but did not correlate with PTH, age or creatinine clearance. In conclusion, hypovitaminosis D is an important, underestimated problem in Italian free-living postmenopausal women referred to an outpatient osteoporosis clinic. Received: 9 February 1998 / Accepted: 8 July 1998     

Nutrient deficiencies in patients with obesity considering bariatric surgery: A cross-sectional study

BackgroundNutritional deficiencies are common after bariatric surgery, but few studies have examined them preoperatively. The objective of this study was to evaluate several vitamins, nutrients, and nutritional markers and their determinants in patients with obesity considering bariatric surgery.MethodsPreoperative values of fasting plasma glucose, insulin, lipid profile, 25-hydroxyvitamin D (25(OH)D), parathyroid hormone, thyroid-stimulating hormone, calcium, phosphate, albumin, magnesium, total proteins, liver function tests, iron, ferritin, folate, vitamin A, vitamin B12, selenium, and zinc were evaluated in 267 Caucasian outpatients (74.2% women, aged 40.5±12.6 years) who were considering bariatric surgery. The determinants of nutrient variability were analyzed by linear regression for nutrients with a prevalence of deficiency>10%, i.e., serum 25(OH)D, iron, phosphate, magnesium, and vitamin A.ResultsPrevalence of inadequate concentrations was high for 25(OH)D (67.9% with values≤20 ng/mL), magnesium (35.4%), phosphate (21.6%), iron (18.8%), and vitamin A (16.9%). Multiple deficiencies were common; 28.5%, 12.1%, and 6.3% of patients had 2, 3, and 4 deficiencies, respectively. In multivariate analyses, metabolic characteristics had an important impact on deficiencies, with lower values of 25(OH)D and vitamin A with increasing body mass index, lower values of 25(OH)D and magnesium with increasing fasting plasma glucose, and a positive correlation between vitamin A and triglycerides. Elevated TSH was associated with low iron concentrations.ConclusionAt all ages, micronutrient deficiencies were common, with high prevalence of concentration inadequacies for 25(OH)D, magnesium, phosphate, iron, and vitamin A. High body mass index and high fasting plasma glucose increased the risk of deficiencies, particularly for 25(OH)D. Preoperative screening and correction of deficiencies should be advised.     

Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery

BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level 相似文献   

A Cross-Sectional Study on Novel-Risk Factors Associated with Supraspinatus Tendon Tear

Background and AimSeveral patient-related factors have been identified which are responsible for the development of rotator cuff tears. The purpose of the study was to assess various parameters which can be risk factors for the development of supraspinatus tendon tear.MethodsA total of 100 patients with symptomatic rotator cuff tear, aged > 18 years, of either gender, presenting to the outpatient department were included in this cross-sectional study. Magnetic resonance imaging was done and based on its results; patients were identified for the type of tear. Demographic, clinical, and biochemical factors affecting the tears were assessed using logistic regression analysis.ResultsFactors such as age, gender, pain radiation, night pain, and analgesic intake had significant association with supraspinatus tendon tears.Conclusion“Pain radiation” and “Analgesic intake” were two new parameters found associated with the supraspinatus tendon tears. New parameters that have been assessed as risk factors will help in better understanding of supraspinatus tendon tears.     

Editorial Commentary: Go Ahead and Repair My Rotator Cuff. I Dare You

A national database in the United States was used to identify increasing age, male sex, smoking, obesity, hyperlipidemia, and vitamin D deficiency as significant independent patient-specific risk factors for rotator cuff repair failure requiring revision repair. Understanding risks for repair failure can help counsel patients, inform treatment strategies, and consider treatment alternatives for patients with symptomatic rotator cuff tears.     

Seasonal Variation in the Deficiency of 25-Hydroxyvitamin D3 in Mildly to Extremely Obese Subjects.

Background  Vitamin D deficiency is a common finding in obese subjects even before any bariatric operation. However, most previous studies reporting on high rates of vitamin D deficiency in obese subjects have not systematically controlled for seasonal variations. Furthermore, the existence of seasonal variation in serum 25-hydroxyvitamin D₃ levels has not been well documented in obese subjects so far. Methods  Serum 25-hydroxyvitamin D₃ levels were measured in 248 obese subjects (body mass index: range, 30.1–68.9 kg/m²). Fat mass was determined using standard bioelectrical impedance analysis. Results  Serum 25-hydroxyvitamin D₃ levels decreased with the increasing body mass index and fat mass (both P < 0.001) and showed a marked variation across the seasons of the year (P < 0.001), which was not affected by the degree of obesity. According to the variation in absolute levels, the prevalence of vitamin D deficiency (<50 nmol/l) was 3.8-fold higher during winter than during summer (91.2% vs. 24.3%; P < 0.001). Conclusion  Data show a marked seasonal variation in absolute serum 25-hydroxyvitamin D₃ concentrations and prevalence of vitamin D deficiency in subjects with mild to extreme obesity. Considering the increasing number of studies reporting on vitamin D deficiency in obesity, the present finding points to season as a crucial factor that should not be neglected when assessing serum levels of this vitamin in obese subjects.     

High prevalence of vitamin K and D deficiency and decreased BMD in inflammatory bowel disease

Summary  Vitamin K and D deficiency and decreased bone mineral density (BMD) were highly prevalent in patients with inflammatory bowel disease (IBD), especially Crohn’s disease (CD). Dietary intakes of these vitamins, however, were above the Japanese adequate intakes in IBD patients, suggesting that malabsorption is the basis for hypovitaminosis K and D and decreased BMD. Introduction  We have studied the possible involvement of vitamin K and D deficiency in the pathogenesis of decreased BMD in IBD. Methods  Seventy patients with IBD were evaluated for their BMD; plasma levels of vitamin K; phylloquinone (PK), menaquinone-7 (MK-7), and 25OH-D; serum PTH, protein induced by vitamin K absence (PIVKA-II), and undercarboxylated osteocalcin (ucOC) levels; and their food intake. Results  Compared with ulcerative colitis (UC) patients, CD patients had significantly lower plasma vitamin K and 25OH-D concentrations; significantly higher serum levels of PTH, PIVKA-II, and ucOC; and significantly lower BMD scores at almost all measurement sites. More IBD patients were vitamin K deficient in bone than in liver. Multiple regression analyses revealed that low plasma concentrations of vitamin K and 25OH-D were independent risk factors for low BMD and that they were associated with the patients’ fat intake, but not with their intake of these vitamins. Conclusion  IBD patients have high prevalence of decreased BMD and vitamin K and D deficiency probably caused by malabsorption of these vitamins.     

High-dose oral vitamin D3 supplementation in rheumatology patients with severe vitamin D3 deficiency

ObjectivesRecent large trials indicate that adherence associated with a daily regimen of vitamin D is low and limits anti-fracture efficacy with vitamin D supplementation. The aim of this report is to describe changes of 25-hydroxyvitamin D (25(OH)D) serum concentrations achieved with a single oral dose of 300 000 IU vitamin D3.MethodsOver a course of 4 months, we identified 33 elderly with severe vitamin D deficiency (25(OH)D < 25 nmol/l) on admission to acute care. Patients were admitted for musculoskeletal pain, bone disease, or gait abnormalities. The mean age was 80.5 years (SD ± 6.1). All patients were treated with a single oral dose of 300 000 IU D3 in combination with 500–1000 mg calcium supplements per day depending on their dietary calcium intake.ResultsBaseline mean 25(OH)D serum concentrations were 15 nmol/l (SD ± 5.5). Mean 25(OH)D serum concentrations increased to 81.4 nmol/l (SD ± 29.7) at 3 months (29 patients) and were still 69.0 nmol/l (SD ± 17.9) at 6 months (26 patients). Mean serum calcium levels were 2.24 mmol/l (SD ± 0.11) at baseline, 2.28 mmol/l (SD ± 0.18) at 3 months, and 2.28 mmol/l (SD ± 0.13) at 6 months. Two patients with mild hypercalcemia (2.69 mmol/l) at 3 months had normal values at 6 months.ConclusionBased on our observations, a single oral dose of 300 000 IU vitamin D3 raises mean 25(OH)D serum concentrations to the target mean of above 75 nmol/l at 3 months and a mean level of 69 nmol/l at 6 months. As calcium absorption is enhanced with higher 25(OH)D serum concentrations, calcium supplementation may need downward adjustment with this regimen to avoid mild hypercalcemia.     

Serum vitamin D metabolites and nuclear uptake of (H)-1,25-dihydroxyvitamin D3 in monocytes from patients with autosomal dominant osteopetrosis: A study of two radiological types

The nuclear uptake of (³H)-1,25 dihydroxyvitamin D₃ in freshly isolated human monocytes and the serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were investigated in 13 patients with autosomal dominant osteopetrosis and in sex- and age-matched controls. Seven patients had type I osteopetrosis characterized by diffuse, symmetrical osteosclerosis with pronounced sclerosis of the skull and increased thickness of the cranial vault. The other six patients had type II with “Rugger Jersey Spine” and “endobones” as characteristic findings. In type I osteopetrosis the serum 1,25-dihydroxy vitamin D was significantly reduced (p < 0.05), whereas serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D receptor binding were normal. In type II osteopetrosis the serum vitamin D metabolites were normal, as was the maximal binding capacity (Bmax) of 1,25-dihydroxyvitamin D to the nuclear receptor. The dissociation constant (Kd), however, was significantly increased (p < 0.01) indicating a modest resistance to 1,25-dihydroxyvitamin D. It is concluded that a general end-organ resistance to 1,25-dihydroxyvitamin D at the receptor level does not exist in type I osteopetrosis, but may contribute to some of the radiological and biochemical findings in type II.