Bone mineral density and biochemical markers of bone turnover in healthy elderly men and women

Abstract

Background. Osteoporosis risk in middle-aged women is twofold greater than that in men, and the difference increases with age. Gender differences in bone mineral density, estimated rates of bone loss, and usefulness of markers of bone metabolism for predicting bone density have not been well described in healthy elders aged 65 and above. The purpose of this cross- sectional analysis was to describe associations of bone mineral density at the hip, spine, and whole body with age, serum osteocalcin, and urinary N- telopeptide crosslinks of Type I collagen in healthy elderly men and women. Methods. A total of 1,087 healthy adults (273 men and 814 women) aged 65 to 87 years were enrolled in a collaborative study at 3 sties: Tufts University (Boston, MA), University of Connecticut Health Center (Farmington, CT), and Creighton University (Omaha, NE). Bone mineral density (BMD) at three regions of the hip, the lumbar spine, and whole body was determined by dual energy x- ray absorptiometry. Serum osteocalcin was measured by immunoassay, and measurement of N-telopeptide crosslinks (Ntx) in urine was made using an enzyme linked radioimmunoassay (ELISA). Results. Among women, the age- related decline in BMD at all non-spine skeletal sites was significantly different from zero, with the largest decline seen at the femoral neck (- .0038 g/cm2/y, p