براساس هورمون پراتيروييد و تغييرات تراكم معدني استخوان D تعيين مقادير نرمال ويتامين

Normal range of vitamin D: relationship between serum PTH and bone mineral density

Objective(s): To quantify the relationship between scrum PTH, vitamin D and bone mineral density to determine normal range of vitamin D in normal population. Methods: A total of 830 healthy individuals aged 30 to 76 years old (60.8% women, 39.2% men) living in Tehran were randomly selected, following exclusion of people suffering from endocrine, rheumatologic or chronic diseases, fractures, other conditions or using drugs that affecting bone metabolism. Vitamin D and Ca intakes were assessed with a food frequency questionnaire. Self reported daily time of sun exposure was used to categorize exposure to sunshine. All participants underwent clinical examination and lumbar spine and proximal of femur BMD by using dual-energy X-ray absorptiometry technique. Plasma level of 25(011) D, Ca, Phosphate (P), Alkaline phosphatase (ALK P), parathyroid hormone (PTH) measured during winter. The correlation between these results was investigated. Results: PTH correlated inversely with 25(OH)D .ln multivariate analysis PTH correlated inversely with whole body BMD (mostly lumbar spine) but not with the hip BMD. No association was found between 25a(OH)D levels and BMD at any site in univariate or multivariate analysis. Based on this relationship between PTH, vitamin D and BMD we obtained normal range of vʹtamin D. Cut -off point for sever vitamin D deficiency was lower than I8nmol/l and range of moderate & mild were 18-23 & 23-36 nmol/l, respectively. Conclusion: Normal range determination of vitamin D based on relationship between PTH, vitamin D and BMD can be shown biological bone variation and is useful in prevention strategy.