Boys with haemophilia have low trabecular bone mineral density and sarcopenia, but normal bone strength at the radius

Abstract

Although a decreased areal bone mineral density (BMD) has been reported in patients with haemophilia, data are lacking that would reflect the three-dimensional structure of the bone and the muscle-bone relationship. We aimed to assess volumetric BMD, bone geometry and muscle-bone phenotype in boys with haemophilia, and to describe the association between clinical characteristics of haemophilia and bone quality and structure. A cross-sectional study was conducted in 41 boys with haemophilia (mean age 12.4, range 6.6-19.8 years) using peripheral quantitative CT (pQCT) at the nondominant forearm. Results were transformed into Z-scores using previously published reference data. Significant differences were tested by one-sample t-test or sign test. Two-sample t-test and anova were used to compare results between subgroups of patients divided according to the severity of the disease, the fracture history and the number of joint and muscle bleedings. Boys with haemophilia had a decreased trabecular volumetric BMD (mean Z-score -0.5, P < 0.01), while their cortical volumetric BMD was increased (mean Z-score 0.4, P < 0.05). The volumetric bone mineral content and the bone geometry at the radial diaphysis were normal when adjusted for patients' shorter body height. Muscle area was decreased (mean Z-score -1.0, P < 0.001), irrespective of age. No association was observed of bone quality parameters and bone geometry with the disease severity, fracture history or number of bleedings. Bone strength measured at the diaphysis of the radius is not impaired in boys with haemophilia. The finding of the decreased trabecular bone density can be most likely attributed to their sarcopenia.

Vitamin D deficiency and osteoporosis in hemophilic children

“…In this study there was a negative association between total joint scores (indicating high grade of hemophilic arthropathy) and 25(hydroxy) D concentrations which was also previously reported [21,27,28]. This may be explained by the possibility that joint damage causes reduced mobility and outdoor activity, accordingly decreased sun exposure.…”

Haemophilia A and B as a cause for secondary osteoporosis and increased fracture risk

“…An accumulating body of evidence over the last decade supports the association between haemophilia and low BMD, both in adults [6][7][8] and children [9]. Regarding its prevalence, most studies have yielded percentages as high as 50-80% [7,8].…”

“…The available data have documented low trabecular BMD in children with haemophilia compared with their healthy age-and sex-matched controls, without difference in cortical bone [9,12], although some studies evaluated only BMD in the lumbar spine [13]. The exact prevalence of low BMD (Z score less than À2.0) in children is unknown (7.5% in one study) [12].…”

“…Of note, these studies were conducted in the Mediterranean region (in Greece and Turkey respectively). Decreased mobility and concomitant reduced sun exposure provide the most plausible explanation, as an inverse association between total joint scores (indicating a high degree of haemophilic arthropathy) and 25(OH)D concentrations was also reported [6,9]. However, others did not find any difference between patients and controls, with regard to vitamin D status [7].…”

“…The degree of arthropathy, either defined as a total clinical score [9] or as a number of target-joints [32], has been also identified as an independent risk factor for low BMD. A positive correlation between the number of affected joints and b-ALP concentrations has been shown, indicating increased bone metabolism in these patients [16].…”