Whole Body and Regional Bone Mineral Content and Density in Women Aged 20-75 years

Dual-energy X-ray absorptiometry (DXA) allows measurement of whole body (WB) and regional bone mineral content (BMC) and density (BMD).To measure WB and regional bone area, BMC and BMD (arms, legs, ribs and pelvis) in women of different ages.140 women participated (age range 20-75 yrs). Three subgroups were built: 20-44 yr (30 premenopausal women), 45-59 (80 women), and 60-75 (30 women). WB DXA was performed on a Hologic QDR 4500 A bone densitometer (Hologic Inc., Bedford MA). WB BMD T-scores were calculated by using the manufacturer-provided and the NHANES 1999-2004 reference databases, while the WB BMC Z-scores - based on the latter. Statistical analysis was performed on an IBM SPSS Statistics 19.0 for Windows platform (Chicago, IL).WB BMC and BMD Z-scores were consistently lower than the reference databases showing a difference of about 0.4 - 0.5 SD. The arms, legs and ribs lost more BMC after the age of 50-55, while the pelvis - much earlier. The total decreases in BMC were highest in the pelvis (26.36 %), followed by the arms (16.81 %) and whole body (15.91 %), while the bone area decreased mostly in the pelvis (13.23 %).The age-related declines in regional BMC, bone areas and BMD follow different patterns in appendicular and axial bones.