The new dual X-ray and laser technology (DXL) gives a more accurate determination of bone mineral density (BMD) than ordinary dual X-ray absorptiometry (DXA) technology because of the ability to eliminate fat tissue both inside and outside the measured bone. In this study the reference database for BMD measured at the calcaneus by the DXL Calscan device is reported. The database was obtained from 993 healthy women and 459 healthy men in a population from southern Sweden. Inclusion criteria were: healthy Swedish Caucasians, 15-85 yr of age for women and 19-85 yr of age for men, no history of osteoporosis treatment, no use of corticosteroids for more than 3 mo, and no extended bed rest. The young adult reference mean BMD for women was found to be 0.483 +/- 0.062 g/cm2 and for men 0.556 +/- 0.074 g/cm2. The age-adjusted odds ratio was 3.7 for a history of fracture among women aged 50 yr and over, comparing subjects with a 1-SD reduction in bone density to subjects with a bone density above this value. The DXL Calscan device used for the study was calibrated weekly against a heel bone phantom. The precision of these measurements was 0.5%. The in vivo precision was 1.2%, as assessed by duplicate measurements on 35 healthy individuals (mean age 52 yr, range 25-72 yr).