VITAMIN D DEFICIENCY IS ASSOCIATED WITH CORTICAL BONE LOSS AND FRACTURES IN THE ELDERLY.
Eur J Endocrinol. 2019 Aug 1. Epub 2019 Aug 1. PMID: 31484162
Francisco de Paula Paranhos Neto
INTRODUCTION: The role of vitamin D on bone microarchitecture and fragility is not clear.
OBJECTIVE: To investigate whether vitamin D deficiency (25(OH)D<20 ng/mL) increases cortical bone loss and the severity of fractures.
DESIGN: Cross-sectional study of 287 elderly women with at least one prevalent low-impact fracture.
METHODS: Biochemistry, X-rays to identify vertebral fractures (VFs) and to confirm non-vertebral fractures (NonVFs), and high resolution peripheral quantitative computed tomography (HR-pQCT) to evaluate bone microstructure.
RESULTS: Serum 25(OH)D levels were associated with body mass index (BMI: r= -0.161 p=0.006), PTH (r= -0.165 p=0.005), CTX (r=-0.119 p=0.043) and vBMD at cortical bone (Dcomp: r= 0.132 p=0.033) and entire bone (D100: r= 0.162 p=0.009) at the distal radius, but not at the tibia. Age and PTH levels were potential confounding variables, but in the multiple linear regressions only BMI (95% CI 0.11 - 4.16; p<0.01), 25(OH)D (95% CI -0.007 - 1.70; p=0.05) and CTX (95% CI -149.04 - 21.80; p<0.01) predicted DComp, while BMI (95% CI 1.13 - 4.18; p<0.01) and 25(OH)D (95% CI 0.24 - 1.52; p<0.01) predicted D100. NonVFs predominated in patients with 25(OH)D<20 ng/mL (p=0.013). Logistic regression analysis showed a decrease in the likelihood of presenting grade 2-3 VFs / NonVFs for every increase in 25(OH)D (OR = 0.962, 95% CI 0.940 - 0.984; p=0.001), BMI (OR = 0.932, 95% CI 0.885 - 0.981; p=0.007) and D100 at radius (OR = 0.994, 95% CI 0.990 - 0.998; p=0.005).
CONCLUSION: In elderly patients with prevalent fractures, vitamin D deficiency was associated with cortical bone loss and severity of fractures.