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Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners

Citation

Iuliano-Burns, S and Wang, XF and Ayton, J and Jones, G and Seeman, E, Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners, Osteoporosis International, 20, (9) pp. 1523-1528. ISSN 0937-941X (2009) [Refereed Article]

DOI: doi:10.1007/s00198-008-0830-9

Abstract

Summary Serum 25(OH)D levels decline without sunlight exposure. We studied 120 expeditioners to Antarctica to determine the skeletal and hormonal responses to sunlight deprivation. With emerging vitamin D insufficiency, serum calcium decreased, PTH increased, and bone loss at the proximal femur was observed. Baseline serum 25(OH)D levels >100 nmol/L prevented vitamin D insufficiency. Introduction Vitamin D stores deplete without adequate sunlight exposure unless supplementation is provided. We studied 120 healthy adults who spent a year in Antarctica as a model for sunlight deprivation to define the timing and magnitude of the skeletal and hormonal responses to emerging vitamin D insufficiency. Methods Fasting blood samples were assessed at baseline, 6 and 12 months for serum 25-hydroxyvitamin D (25(OH)D), osteocalcin (OC), bone formation (P1NP) and resorption (CTx), PTH and calcium. Lumbar spine and proximal femur BMD was measured using DXA. Differences over time were determined using repeated measures ANOVA. Percent changes were expressed as ( value/(value A+value B)/2)~100. Relationships between outcome measures were determined using Spearmanfs correlations. Results Vitamin D insufficiency (<50 nmol/L) was observed in 85% of expeditioners by 6 months when serum calcium decreased and PTH increased (p<0.01). By 12 months, OC increased by 7.4}3.0% (p<0.05), and BMD decreased by 1.0}2.0% at the total proximal femur (p<0.05). For those with vitamin D sufficiency at baseline (>50 nmol/L), sunlight deprivation produced vitamin D insufficiency within 4 months unless baseline values were >100 nmol/L. Conclusion Supplementation may be necessary for expeditioners with limited access to UV light.

Item Details

Item Type:Refereed Article
Keywords:Bone loss, Sunlight, Vitamin D
Research Division:Medical and Health Sciences
Research Group:Clinical Sciences
Research Field:Rheumatology and Arthritis
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Skeletal System and Disorders (incl. Arthritis)
Author:Jones, G (Professor Graeme Jones)
ID Code:60394
Year Published:2009
Web of Science® Times Cited:9
Deposited By:Menzies Institute for Medical Research
Deposited On:2010-02-03
Last Modified:2011-07-28
Downloads:0

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