Endocrine Abstracts

Introduction: The 25hydroxyvitamin(OH)D deficiency has been linked to the risk of postmenopausal fractures and osteoporosis. In Colombia,the prevalence of 25(OH)vitaminD deficiency is high, reaching more than 53% of the total population. It can be stated that hip fracture is one of its most feared complications, with a high risk of mortality and morbidity,which can affect even osteopenic patients. The objective of this study is to assess modifications in hip T-score (using dual-energyX-ray absorptiometry(DXA)), that are related and influenced by changes in 25(OH)vitaminD levels in Colombian postmenopausal women.

Methodology: This study is a cross-sectional analysis that uses linear regression to determine the changes of hipT-score value (standard deviation(SD)) according to vitaminD levels, it is adjusted to serum calcium, phosphorus, paratohormone levels and age. To establish the validity of the model: the homocedasticity and normality of the residues were exhibited;Cook’s distance<2 and colinearity was ruled out (VIF<10). VitaminD deficiency was defined as a value of 25(OH)vitaminD below 20 ng/ml (50 nmol/l),and vitaminD insufficiency as a value between 21 and 29 ng/ml(3).

Results: 124 Postmenopausal women were included at mean age of 66.07±11.28 years; with average levels of serum calcium:9.53±0.60 mg/dl; mean of paratohormone:57.06±27.14 pg/ml; mean vitamin25(OH)D:25.69±9.22 ng/ml; mean serum phosphorus: 3.62±0.61 mg/dl; mean hip T-score: −1,92±1,18; mean hip Z-score:0,058±0,80; hip bone mineral density:0,833±0,095;g/cm²; 22.08% of patients had a deficiency of 25(OH)vitaminD and 53.25% had insufficiency of 25(OH)vitaminD; 31% of patients had osteoporosis and 53% osteopenia. The linear regression model found that a 25 (OH) vitamin D change of 0.042±0.20 ng/ml (95% CI 0.012–0.083, P=0.04) produces a change of 1 (one) standard deviation in hip T-score; adjusting to levels of paratohormone, serum calcium, serum phosphorus and age; constant value −6.34.The linear regression equation would be:HipT-score=6.34+0.042(25(OH)vitaminD). The model explains 22% of the changes in the T-score, the residuals were homocedastic and normal (P=0.70); there was no collinearity (average VIF=1.11) and distance of cook=0.064.

Conclusion: This study tries to demonstrate how very small variations in the levels of 25(OH)VitaminD, can significantly influence changes of up to 1(one)SD in hip T-Score of postmenopausal women.