Positive Association between Total Lymphocyte Count and Femur Bone Mineral Density in Hip-Fractured Women

Abstract

Background: Protein depletion appears to play a detrimental role in the causes of hip fracture and low bone mineral density has been observed in protein-depleted subjects. Objective: To investigate the association between femur bone mineral density and total lymphocyte count, a marker of the protein nutrition status, in elderly hip-fractured women. Methods: 210 white women affected by their first hip fracture either spontaneous or due to minimal trauma consecutively admitted to a rehabilitation hospital were studied. 34 women were ruled out because of confounding factors altering their lymphocyte count. Both total lymphocyte count and bone mineral density at the unfractured femur were evaluated. The correlation between these two variables was studied by Pearson’s coefficient. Bonferroni adjustment was used for multiple comparisons. Bone density was measured by DXA (Hologic QDR 4500W). Results: A positive correlation was observed between lymphocyte count and bone mineral density measured at both total proximal femur (r = 0.21; p < 0.05) and intertrochanteric area (r = 0.21; p < 0.05). Stepwise linear multiple regression analysis showed that the association with total lymphocyte count was independent of age, weight, height, body mass index, time between surgery and blood sample collection for lymphocyte count and type of hip fracture (cervical or trochanteric) when bone mineral density was evaluated both at total proximal femur (p < 0.05) and intertrochanteric area (p < 0.05). Conclusion: Our results support the role exerted by protein nutrition in bone health, at least in elderly frail women. From this point of view, a total lymphocyte count is a suitable, inexpensive marker.