Bone mineral density of the spine and femur in healthy Saudis.

The reference values of bone mineral density (BMD) were determined in healthy Saudis of both sexes and compared with US / northern European and other reference data. BMD was determined by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and femur including subregions: trochanter, Ward's triangle, and neck, in 1,980 randomly selected Saudis (age range 20-79 years; 915 males and 1,065 females) living in the Jeddah area. Age-related changes in BMD were similar to those described in US / northern European and Lebanese reference data. Decreases in BMD of males were evident (% per year): 0.3-0.8 (lumbar spine), 0.2-0.4 (femoral trochanter), 0.2-1.4 (Ward's triangle), and 0.2-0.7 (femoral neck). Also, decreases in BMD of females were observed (% per year): 0.8-0.9 (lumbar spine), 0.7-0.9 (Ward's triangle), and 0.3-0.7 (femoral neck). Using stepwise multiple regressions that included both body weight and height, the former had 2-4 times greater effect on BMD than the latter. Using the mean BMD of the <35-year-old group the T-score values were calculated for Saudis. The prevalence of osteoporosis in Saudis (50-79 years) at the lumbar spine using the manufacturer's vs Saudi reference data was 38.3-47.7% vs 30.5-49.6 (P<0.000), respectively. Similarly, based on BMD of total femur, the prevalence of osteoporosis using the manufacturer's vs Saudi reference data was 6.3-7.8% vs 1.2-4.7% (P<0.000), respectively. Saudis (> or =50 years) in the lowest quartile of body weight exhibited higher prevalence of osteoporosis (25.6% in females and 15.5% in males) as compared to that of the highest quartiles (0.0% in females and 0.8% in males). The present study underscores the importance of using population-specific reference values for BMD measurements to avoid overdiagnosis and/or underdiagnosis of osteoporosis.