Parathyroid hormone is significantly associated with body fat compartment in men but not in women following a hip fracture.

Background And Aims: Parathyroid hormone (PTH) exerts several actions beyond mineral metabolism and may affect body composition. The aim of our study was to assess the association between serum PTH and body fat compartment in hip fracture patients.

Methods: We studied 575 of 630 inpatients with hip fracture consecutively admitted to our Rehabilitation ward. Dual-energy X-ray absorptiometry (DXA) was used to measure body composition. DXA scan was performed 18.5 ± 8.6 (mean ± SD) days after hip fracture occurrence. A blood sample was collected within 4 days after DXA scan. In each subject, we evaluated PTH, 25-hydroxyvitamin D, calcium, phosphate, albumin, magnesium, and creatinine. Glomerular filtration rate was estimated by a conventional formula.

Results: In the 57 men, we found a significant correlation between PTH and both body mass index (BMI) (ρ = 0.37; p = 0.020) and trunk fat percentage (ρ = 0.62; p < 0.001). After multiple adjustments, we confirmed a significant association between PTH and BMI (r = 0.38; p = 0.004) or trunk fat percentage (r = 0.51; p < 0.001). In the 518 women, we found a slightly significant correlation between PTH and BMI (ρ = 0.09; p = 0.047), but after adjustments the correlation coefficient dropped to 0.02 (p = 0.69). We found no significant relationships between PTH and trunk fat percentage at bivariate correlation (ρ = 0.04; p = 0.35) or after adjustments (r = 0.04; p = 0.38).

Conclusions: PTH serum levels were robustly associated with body fat compartment in men, but not in women following a fracture of the hip. A role of PTH in affecting body composition in hip fracture men is suggested. Its potential role in male prognostic disadvantage needs further investigation.