Bone demineralisation in a large cohort of Wilson disease patients

We compared the bone mineral density (BMD) of adult Wilson disease (WD) patients (n = 148), with an age- and gender-matched healthy control population (n = 148). Within the WD cohort, correlations of BMD with WD disease parameters, lab results, type of treatment and known osteoporosis risk factors were analysed.

Hip and lumbar spine absolute BMD and T-score were measured by dual-energy X-ray absorptiometry. Osteoporosis and osteopenia were defined as a T-score ≤ −2.5, and between −1 and −2.5, respectively.

There were significantly more subjects with abnormal T-scores in the WD population (58.8 %) than in the control population (45.3 %) (χ² = 6.65, df = 2, p = 0.036), as there were 50.0 % osteopenic and 8.8 % osteoporotic WD patients, vs. 41.2 % and 4.1 %, respectively, in the controls. Especially L2-L4 spine BMD measurements (BMD and T-scores) differed significantly between the WD population and matched controls. L2-L4 spine BMD for WD patients was on average 0.054 g/cm² (5.1 %) lower than in matched normal controls (0.995 ± 0.156 vs 1.050 ± 0.135; p = 0.002). We found no significant correlation between BMD values and any of the WD disease parameters (e.g. the severity of liver disease), lab results, type of treatment or known osteoporosis risk factors. Duration of D-penicillamine treatment was negatively correlated with femoral BMD value, but in a clinically irrelevant manner, compared to age and gender. Importantly, BMD remained significantly lower in WD patients (n = 89) vs. controls after excluding WD patients with cirrhosis (p = 0.009).

Our study suggests that WD is intrinsically associated with bone demineralisation.