Bone Mineral Density Measurements of Women in a Black African Population in Lagos, Nigeria Using Accudexa Bone Mineral Density Assessment System: A Preliminary Study.

Objective: No normative database for bone mineral density (BMD) exists in Nigeria. This study aims to provide the basis for the creation of a normative reference BMD database for women in Nigeria while assessing the appropriateness of applying normative data for African American women to Nigerian females.

Methods: Bone mineral density measurements of 70 women aged 50 years and above as well as 58 women aged between 23 and 30 years were taken using an accuDexa Dual X-ray Absorptiometry (DEXA) machine. Local T-scores were determined using the BMD measurements of the young healthy normal group as control and the patients were grouped using the World Health Organization definitions (WHO) classification into normal, low bone density and osteoporosis. This was compared with the T-scores obtained using the African American normative database.

Results: Using the local reference to determine T-scores for the older women, 24 were normal, 32 had low bone density and 14 had osteoporosis. When the African American database was used as reference, 31 were normal, 31 had low bone density and eight had osteoporosis. This gave a diagnostic difference of 10% for the normal group, -1.4% for the low bone density group and -8.6% for the osteoporosis group.

Conclusion: Preliminary results suggest that the BMD of the local young healthy normal female Nigerian is higher than the African American female. Since the diagnostic difference for osteoporosis is greater than 5%, the African American reference values are considered inappropriate for diagnosis of osteoporosis in the female Black Nigerian. There is a need for a larger multicentre study to evaluate these findings.