Clinical data
Participant clinical data including age at first blood transfusion,
frequency and volume of each blood transfusion, pre-transfusion Hb,
endocrine complications and medications were retrieved from the
electronic medical record. We also collected concentrations of serum
25-hydroxy vitamin D (25OHD) and ferritin (assessed every 3-4 months)
and liver iron concentration (LIC) measured by MRI (annually). Fracture
history was acquired through an interview.