Determinants of plasma 25-hydroxyvitamin D levels in healthy adults in the Netherlands.

BACKGROUND: Vitamin D plays a key role in maintaining skeletal health, but is also related to various non-skeletal health issues. Several determinants have been identified that influence blood plasma levels of 25-hydroxyvitamin D (25(OH) D), often in specific patients or elderly populations. This paper aims to replicate these findings in a healthy population. METHODS: Plasma levels of 25(OH)D were measured using tandem mass spectrometry. We examined the cross-sectional association of sociodemographic, health, lifestyle and sampling characteristics with 25(OH)D in a group of 539 adults, who were healthy control subjects in the NESDA study in the Netherlands (latitude 52 °N). RESULTS: Mean 25(OH)D levels were 68.0 (± 27.2) nmol/l. Levels under 50 nmol/l occurred in 27% of the population; 40% reached levels above 75 nmol/l. Women had higher levels than men, and the use of oral contraceptives showed a significant positive association among females. Subjects with non-European ancestry had dramatically lower 25(OH) D levels. Other factors that were negatively associated were body mass index and the renal estimated glomerular filtration rate (eGFR). Meteorological data replaced season as a significant determinant. Moderate alcohol consumption and sports showed a positive association, while physical activity and the hepatic marker gamma-glutamyl transferase did not. Our results disconfirm the influence of age in this population of under 65 year olds. CONCLUSION: Insufficient 25(OH)D levels were common in a healthy population. The set of eight variables that were significant in a multiple regression model (sex, ancestry, oral contraceptives, eGFR, BMI, sports, alcohol, sunshine) explained 29.5% of the variance.

Prevalence of vitamin D deficiency and consequences for PTH reference values.

Reference values of PTH depend on vitamin D status of the reference population. This is often not described in package inserts. The aim of the present study was therefore to calculate assay specific PTH reference levels in EDTA plasma for the Architect (Abbott) in relation to 25-hydroxyvitamin D (25OHD) levels. The relation between PTH levels, 25OHD, BMI, age, gender and kidney function was determined in a cohort of older individuals from the Longitudinal Aging Study Amsterdam (LASA, n = 738, age 55-65 years) and in a cohort of healthy individuals from the Netherlands Study of Depression and Anxiety (NESDA, n = 633, 18-65 years). The LASA cohort is a representative sample of the Dutch older population. As expected, PTH reference values were significantly lower in 25OHD sufficient subjects (25OHD>50 nmol/L) than in 25OHD deficient and insufficient subjects. The 97.5th percentile of PTH in 25OHD sufficient subjects was 10 pmol/L (94.3 pg/mL), which was higher than the upper limit stated by the manufacturer (7.2 pmol/L or 68.3 pg/mL). The relation between vitamin D and PTH was independent of age, gender, BMI and kidney function. In conclusion, we have shown that it is important to establish PTH reference values in a local reference population taking 25OHD status into account.

[Vitamin D supplementation in the elderly: guidelines and practice]. / Vitamine D-suppletie bij ouderen: advies en praktijk.

OBJECTIVE: In 2008, the Health Council of the Netherlands published an advice on vitamin D supplementation for the elderly. Nevertheless, suspicion arose at the Ministry of Health, Welfare and Sport and the Netherlands Nutrition Centre that vitamin D supplementation in the elderly is still insufficient. We aimed to determine the extent to which general practitioners and elderly care physicians actually followed the advice of the Health Council. DESIGN: Questionnaire study. METHOD: Brief questionnaires were sent to all elderly care physicians in the Netherlands. Some questions were also posed to general practitioners at a network meeting of the Academic Network of GP Practices of the VU University Medical Center in Amsterdam. RESULTS: More than two-thirds of the respondents, both elderly care physicians and general practitioners, are familiar with the guidelines of the Health Council of the Netherlands on vitamin D supplementation in the elderly, but about half do not prescribe vitamin D when the guideline advises to do so. When supplementation is prescribed, about half of the elderly care physicians and a fifth of the general practitioners uses an insufficient dose. CONCLUSION: The guidelines of the Health Council of the Netherlands on vitamin D supplementation in the elderly are not sufficiently followed by elderly care physicians and general practitioners. Awareness of and support for the vitamin D supplementation guidelines among health care providers is still limited.

Severe progressive osteoporotic spine deformity with cardiopulmonary impairment in a young patient. A case report.

STUDY DESIGN: This report describes a young patient with a rapidly progressive kyphosis caused by collapse of a severely osteoporotic thoracolumbar spine, which led to impairment of cardiopulmonary function. OBJECTIVES: To highlight the treatment strategy, difficulty of diagnosis, operative stabilization, and outcome. SUMMARY OF BACKGROUND DATA: Little is known about natural history, treatment options, and results of this condition. METHODS: The magnitude of bone loss was measured by dual-energy x-ray absorptiometry, and the deformity was visualized by computed tomography and magnetic resonance imaging. Laboratory investigations also were performed before and during halotraction in an attempt to establish a diagnosis. These data constituted the preoperation information required to assess later results of medical and surgical intervention. RESULTS: An extensive evaluation of possible underlying etiologies failed to identify a specific etiology. Before and during halotraction, bone mineral substitutes were given, partially correcting the bone mineral content as measured on repeated dual-energy x-ray absorptiometry scans. In addition, the thoracic kyphosis was partially corrected, from 100 degrees to 70 degrees Cobb's angle. Subsequently, a combined anterior and posterior stabilization was performed from C7 to S1 using a vascularized fibula graft, a double Isola rod system (AcroMed, Cleveland, OH), and a carbonate apatite cancellous bone cement to reinforce the pedicle screws. At follow-up assessment 40 months surgery, the patient was asymptomatic and fully mobilized, with radiographs showing complete incorporation of the grafts and no loosening of the fixation device. CONCLUSIONS: The diagnostic and therapeutic difficulties of progressive spine deformity caused by severe osteoporosis in young patients emphasizes the importance of a thoroughly planned treatment strategy. Halotraction is recommended to stop progression of the deformity, or even partially correct it, and to allow time to search for the diagnosis and bone mineral substitution. Surgical treatment using vascularized fibular strut grafts and a strong fixation device was successful. Biocompatible carbonated apatite cancellous bone cement was successfully used to reinforce pedicle screw fixation.

Transient osteoporosis and osteogenesis imperfecta. A case report.

The authors report migratory transient osteoporsis of the ipsilateral hip and ankle in a patient with ostengenesis imperfecta. The diagnosis was made with modern imaging techniques (magnetic resonance imaging, bone scintigraphy, and dual energy xray absorptiometry). Histologic examination after bone biopsy of the proximal femur showed possible microfractures. The treatment consisted of a regimen of nonweightbearing. One year after onset, the patient had no symptoms and no residual evidence of transient osteoporosis on radiographic studies. The etiology of transient osteoporosis in patients who have osteogenesis imperfecta is uncertain. The authors' findings suggest that microfractures may play a role in the early pathophysiologic process.

A study of the importance of fine needle aspiration cytology in the diagnosis of the solitary thyroid nodule.

The results of 287 fine needle aspirations (FNAs) of the thyroid, performed between 1 January 1982 and 31 December 1986, were retrospectively analysed with respect to clinical history, physical examination, scintigraphy and echoscopy, and compared with the results of the histological examination of thyroid tissue removed from the 65 patients who were operated. Except for the follicular tumour group, FNA examination proved to be the best method for differentiating benign and malignant lesions. The specificity was found to be 48%, the sensitivity 86%. The only value of scintigraphy and echoscopy appears to be in their supporting role. Based on these results a new strategy for the evaluation of thyroid nodules is proposed, in which the FNA examination has a more important place in the diagnosis than before.