Low serum vitamin D is associated with higher cortical porosity in elderly men. (15th May 2016)

• Record Type: Journal Article
• Authors: Sundh, D.; Mellström, D.; Ljunggren, Ö.; Karlsson, M. K.; Ohlsson, C.; Nilsson, M.; Nilsson, A. G.; Lorentzon, M.
• Is Part Of: Journal of internal medicine. Volume 280:Number 5(2016:Nov.)
• Page Start: 496
• Page End: 508
• Publication Date: 2016-05-15
• Subjects: cortical porosity -- high‐resolution peripheral computed tomography -- vitamin D; Internal medicine -- Periodicals; Medicine -- Periodicals; 616
• DOI: 10.1111/joim.12514
• Languages: English
• ISSNs: 0954-6820

Abstract

Abstract: Background: Bone loss at peripheral sites in the elderly is mainly cortical and involves increased cortical porosity. However, an association between bone loss at these sites and 25‐hydroxyvitamin D has not been reported. Objective: To investigate the association between serum levels of 25‐hydroxyvitamin D, bone microstructure and areal bone mineral density (BMD) in elderly men. Methods: A population‐based cohort of 444 elderly men (mean ± SD age 80.2 ± 3.5 years) was investigated. Bone microstructure was measured by high‐resolution peripheral quantitative computed tomography, areal BMD by dual‐energy X‐ray absorptiometry and serum 25‐hydroxyvitamin D and parathyroid hormone levels by immunoassay. Results: Mean cortical porosity at the distal tibia was 14.7% higher (12.5 ± 4.3% vs. 10.9 ± 4.1%, P < 0.05) whilst cortical volumetric BMD, area, trabecular bone volume fraction and femoral neck areal BMD were lower in men in the lowest quartile of vitamin D levels compared to the highest. In men with vitamin D deficiency (<25 nmol L −1 ) or insufficiency [25–49 nmol L −1, in combination with an elevated serum level of parathyroid hormone (>6.8 pmol L −1 )], cortical porosity was 17.2% higher than in vitamin D‐sufficient men ( P < 0.01). A linear regression model including age, weight, height, daily calcium intake, physical activity, smoking vitamin D supplementation and parathyroid hormone showed that 25‐hydroxyvitamin D independently predicted cortical porosity (standardized β = −0.110, R 2 = 1.1%, P = 0.024), area (β = 0.123, R 2 = 1.4%, P = 0.007) and cortical volumetric BMD (β = 0.125, R 2 = 1.4%, P = 0.007) of the tibia as well as areal BMD of the femoral neck (β = 0.102, R 2 = 0.9%, P = 0.04). Conclusion: Serum vitamin D is associated with cortical porosity, area and density, indicating that bone fragility as a result of low vitamin D could be due to changes in cortical bone microstructure and geometry.