Author: Li, Man Kei Henry
Title: Parathyroid hormone, vitamin D, calcium & phosphate in plasma of apparently healthy young adults and their inter-relationships
Advisors: Benzie, Iris F. F. (HTI)
Degree: M.Sc.
Year: 2015
Subject: Vitamin D.
Parathyroid hormone.
Blood plasma -- Measurement
Hong Kong Polytechnic University -- Dissertations
Department: Department of Health Technology and Informatics
Pages: 64 leaves : illustrations (some color) ; 30 cm
Language: English
Abstract: Serum 25-hydroxyvitamin D is considered to be the best indicator of overall vitamin D status of an individual. People with vitamin D deficiency will suffer from malabsorption of calcium, secondary hyperparathyroidism, leading to increased bone resorption, accelerated cortical bone loss, and increased fractures. Severe vitamin D deficiency can also cause osteomalacia. Vitamin D status is related to serum PTH. But there is still debate how far the serum vitamin D concentration has to fall to impact significantly on increasing plasma PTH levels, and at what ‘threshold’ level of vitamin D there is no further decrease in PTH a level that could indicate sufficiency, at least in terms of bone health. Objective: (A) Examine the correlation and relationship between plasma PTH and vitamin D status (assessed by plasma 25OHD) in a group of apparently healthy young Chinese adults (N=80, Aged 18-24) in order to seek evidence of a threshold or plateau at which changes in one parameter cease to influence the other; (B) To explore the relationships between PTH, vitamin D, phosphate and calcium in plasma. Design and Participants: This was a cross-sectional analysis. A total of 80 heparinized plasma samples were collected for PTH, calcium and phosphate test. The samples had been collected over around 18 months in 2013-14 from 80 apparently healthy young Chinese students of the Hong Kong Polytechnic University with their informed consent. Results: The mean of 25 (OH)D in this study is 44.92 nmol/L. In this study, the threshold for vitamin D sufficiency was set at the 50 nmol/L cutoff for plasma 25(OH)D. The plasma PTH was inversely correlated with plasma 25OHD (r= -0.313, p=0.005). A significant inverse association between PTH and calcium (r= -0.525 p<.001) was observed, while PTH was directly, though weakly, correlated to phosphate (r=0.26, p= 0.02). No threshold value of vitamin D insufficiency was found. However, the threshold 25 (OH)D value (in relation to effects on PTH) may be within the range of 45-51 nmol/L. Conclusion: Vitamin D insufficiency is common among young Hong Kong people.
Rights: All rights reserved
Access: restricted access

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