Correlation of Body Mass Index and Age with Osteoporosis Probability in Patients with Primary Hyperparathyroidism

Objective: Currently, there are limited markers to predict the osteoporosis probability in patients with primary hyperparathyroidism. We studied the relationship between various parameters and results of DXAs at various skeletal sites. Methods: Retrospective review of data for 218 patients with primary hyperparathyroidism was performed. Age, BMI, bone mineral density, serum total calcium, ionized calcium, intact parathyroid hormone, albumin, alkaline phosphatase, phosphate, 25-hydroxy vitamin D, 1,25-dihydroxy vitamin D, 24-hour urinary calcium levels and parathyroid tumor weight were analyzed. Two different statistical models- linear regression and multivariate logistic regression were performed. Results: At the lumbar spine, with the linear model, BMI (P <.001), alkaline phosphatase (P <.001), and ionized calcium (P <.001) significantly correlated with T scores; whereas with the logistic model, BMI was the only variable predicting osteoporosis probability. At the femoral neck, BMI (P <.022), 25-hydroxy vitamin D (P <.001), 1,25-dihydroxy vitamin D (P <.034) correlated with T scores; whereas both BMI (P <.029) and age (P <.051) were the significant variables that predicted osteoporosis. At the total hip, BMI (P <.001) and age (P <.001) correlated with T scores; whereas with the logistic model, only BMI (P <.016) predicted osteoporosis. At the forearm, a model could not be generated due to limited number. Conclusion: In patients with primary hyperparathyroidism, BMI strongly correlated with T scores and probability of osteoporosis.