Interpreting low normative bone mineral density among Saudi Arabian women

Background: Although results from prior publications have indicated that normative bone mineral density (BMD) in Saudi Arabian women is significantly lower than their North American and European counterparts, there has been no systematic attempt to study these differences across the age spectrum. Objectives: To explore these issues in more detail, a new Saudi Arabian normative BMD dataset was systematically derived from patient data at King Faisal Specialist Hospital & Research Centre in Riyadh. Changes in mean BMD were studied with respect to both age and years-since-menopause. Methods: A retrospective analysis of BMD was carried out among 858 Saudi Arabian women who had undergone routine dual-energy x-ray absorptiometry. In addition to the usual patient details collected at each scan, information from questionnaires summarizing the patient's medical, lifestyle and menopause history was also used to identify a subset of 179 presumed-normal women. Results: The normative BMD results for the L2-L4 AP-spine scans agree very closely with published data describing Jeddah women and indicate that during their postmenopausal years, the BMD of an average Saudi Arabian woman drops from a premenopausal plateau (i.e. peak bone mass) of 1.14 g cm(-2), to a residual postmenopausal plateau of 0.92 g cm(-2). The time-constant for this loss is 4.64 years. Conclusions: We conclude that the average BMD of normal Saudi Arabian women is approximately 0.1 g cm(-2) lower than European women across the entire adult age-range, but that the extent and rate of postmenopausal bone loss appears to lie within the normal European range. This suggests that osteoporosis is first manifested in young adults.