Vitamin D insufficiency: a risk factor to vertebral fractures in community-dwelling elderly women.

OBJECTIVE

To determine the risk factors for the presence of moderate/severe vertebral fracture, specifically 25-hydroxyvitamin D (25-OHD).

STUDY DESIGN

Cross-sectional study conducted for 2 years in the city of São Paulo, Brazil including community-dwelling elderly women.

METHODS

Bone mineral density (BMD), serum 25-OHD, intact parathyroid hormone (iPTH), calcium and estimated glomerular filtration rate (eGFR) were examined in 226 women without vertebral fractures (NO FRACTURE group) and 189 women with at least one moderate/severe vertebral fracture (FRACTURE group). Vertebral fracture assessment (VFA) was evaluated using both the Genant semiquantitative (SQ) approach and morphometry.

RESULTS

Patients in the NO FRACTURE group had lower age, increased height, higher calcium intake, and higher BMD compared to those patients in the FRACTURE group (p<0.05). Of interest, serum levels of 25-OHD in the NO FRACTURE group were higher than those observed in the FRACTURE group (51.73 nmol/L vs. 42.31 nmol/L, p<0.001). Reinforcing this finding, vitamin D insufficiency (25-OHD<75 nmol/L) was observed less in the NO FRACTURE group (82.3% vs. 93.65%, p=0.001). After adjustment for significant variables within the patient population (age, height, race, calcium intake, 25-OHD, eGFR and sites BMD), the logistic-regression analyses revealed that age (OR=1.09, 95% CI 1.04-1.14, p<0.001) femoral neck BMD (OR=0.7, 95% CI 0.6-0.82, p<0.001) and 25-OHD <75 nmol/L (OR=2.38, 95% CI 1.17-4.8, p=0.016) remains a significant factor for vertebral fracture.

CONCLUSION

Vitamin D insufficiency is a contributing factor for moderate/severe vertebral fractures. This result emphasizes the importance of including this modifiable risk factor in the evaluation of elderly women.