Allogeneic Bone Marrow Transplantation is Associated with a Preferential Femoral Neck Bone Loss

Osteoporosis is a major complication of organ transplantation. Little is known about the risk of developing osteoporosis in bone marrow transplant (BMT) recipients. We studied early and late changes in bone mineral density (BMD), as well as biochemical markers of bone remodeling, in patients at the time of allogeneic BMT (alloBMT) and up to 13 years thereafter. In a cross-sectional study, 102 patients (40 women, 62 men, mean age ± SEM, 38.9 ± 1.6 years) were segregated into a first group (A, n= 48) and evaluated before or during the first weeks (mean ± SD 0.3 ± 0.1 month, range –0.5 to 3 months) following alloBMT, and a second group (B, n= 54) studied 60.1 ± 5.6 months (range 6–156 months) following alloBMT. Lumbar spine (LS) BMD was similar in groups A and B and was within normal limits. In contrast, femoral neck (FN) Z- and T-scores were significantly decreased in group B compared with group A (–0.68 ± 0.14 vs –0.03 ± 0.14 SD and –0.84 ± 0.14 vs –0.22 ± 0.14 SD, respectively; p≤0.002). Osteopenia (T-score between –1 and –2.5 SD) was present in 35% of group A and 43% of group B patients (NS). Osteoporosis (T-score <–2.5 SD) was detected in 7% of group B patients, but in none of those in group A (p= 0.05). In a longitudinal study, 56 subjects were evaluated at the time of alloBMT, and 33 and 23 were studied 6 or 12 months later, respectively (13 women, 20 men, 37.5 ± 1.6 years). All were treated with supplements of calcium and vitamin D. Amenorrheic women received hormone replacement therapy (HRT). Three-monthly pamidronate infusions were given to 15 men and 10 non-amenorrheic women who were osteopenic/osteoporotic or had elevated baseline bone turnover markers. Mean baseline LS and FN Z- and T-scores were within normal range. Six months after BMT, FN BMD decreased by 4.2 ± 0.7% (p<0.001), and whole body BMD and bone mineral content by 1.5 ± 0.4% and 3.1 ± 0.6%, respectively (p≤0.0001). Twelve months after the graft, there was no further significant bone loss and only FN BMD decrease remained significantly different compared with baseline (–5.6 ± 1.1%, p≤0.0001). These results indicate that the risk of decreased BMD is higher for the femoral neck than the lumbar spine and whole body levels in patients with allogeneic bone marrow transplantation, and that bone loss occurs mainly during the first 6 months after the graft. Received: 9 February 2001 / Accepted: 23 May 2001