Vertebral bone density in Icelandic women using quantitative computed tomography without an external reference phantom

Abstract

Vertebral trabecular bone mineral density (BMD) was measured in 187 healthy Icelandic women, age 35-64 years, by quantitative computed tomography (QCT) with the use of internal references (muscle and subcutaneous fat) instead of the traditional external references (phantoms). We found a mean 2.4 mg/cm3 (1.8%) bone loss per year in the age range 35-64 years. There was an accelerated phase (exponential) after menopause, with 4% loss per year for the first 1-5 years after menopause or 5-fold trabecular bone loss compared with the subsequent 11-15 years after menopause. Reproducibility was found to be 1.9%. This method thus compares with traditional QCT measurements and is highly reproducible. We find QCT using internal references a promising method for assessing fracture risk in perimenopausal women and for follow-up in osteoporotic patients.