Bone and Osteoporosis Measures
Bone and Osteoporosis Measures began at Visit 5 (1988-92) and continued through Visit 11 (2007-09). This resulted in up to 6 DXA scans of the hip and spine and 5 whole-body scans for each participant over a 20-year period. In addition, several newer bone assessments were conducted including QCT of the hip, vertebral fracture assessment, heel and finger BMD using portable devices, and three measures of kyphosis. Participants from the original cohort were invited to the bone clinic Visits when they reached the eligibility age (most were age 45+), and remained eligible as long as they were ambulatory, community dwelling and able to give informed consent.
Summary of Data Available and Methods by Visit
The number of participants with hip and spine scans at each Bone Health Visit is shown in Table 1. Table 2 shows the number of participants whose BMD was assessed one or more times. Among all RBS participants, BMD was assessed at least once in 2614, at least twice in 1763, etc.
Bone and Osteoporosis Measures by Visit
Visit 5: Between 1988 and 1991, 2,153 participants, aged 34 to 98 (mean 71.4), had anterior posterior (AP) spine and hip bone mineral density (BMD) measured by dual energy x-ray absorptiometry (DXA) using the Hologic 1000, and ultradistal wrist and midshaft radius BMD measured using single photon absorptiometry (SPA).
Visit 7: Between 1992 and 1996, 1,708 participants, aged 30 to 97 (mean 71.0), had repeat DXA of the hip and spine using the Hologic 1000 and first-time DXA scans of the anterior-posterior (AP) spine, the thoracic spine, the lateral lumbar spine and the whole body using the Hologic 2000. Hip axis length was obtained in 947 participants using the Hologic 1000 and repeated in 159 participants using the Hologic 2000.
Visit 8: Between 1997-99, 1,046 participants, aged 37 to 96 (mean 73.6), had total body DXA scans and repeat scans of the hip and lumbar spine BMD using the Hologic 2000.
Visit 9: Between 1998 and 2001, 1,098 participants, aged 42 to 99 (mean 73.7), had repeat DXA of the hip and spine using the Hologic 1000, repeat DXA scans of the anterior-posterior (AP) spine, lumbar spine and whole body using Hologic 2000,and the first heel ultrasound using Hologic Sahara. Lateral x-rays of the thoracic and lumbar spine were repeated.
Visit 10: Between 2003 and 2005, 814 participants, aged 43 to 99 (mean 73.2), had repeat measures of BMD (hip, spine, radius and whole body) and heel ultrasound using the same instruments as Visit 9. Vertebral Fracture Assessment (VFA) using Hologic Delphi DXA was measured for the first time. Lateral spine x-rays were repeated. Visit 11: Between 2007 and 2009, 630 participants, aged 50 to 104 (mean 75.7), had repeat measures of BMD (hip, spine, radius and whole body), lateral spine x-rays, VFA (vertebral fracture assessment) and heel ultrasound using the same instruments as prior visits. QCT (quantitative computed tomography) of the femoral neck of the hip was obtained for the first and only time.
Fracture history was obtained at each research clinic Visit and via multiple Mailers using self-administered questionnaires. Participants were queried by fracture site for fracture (yes/no), year of fracture, age of fracture and cause of fracture (chosen from a list of 9 codes severe trauma, 3 types of falls, spontaneous fracture, and local bone disease). The time frame for the fracture history questions varied by Visit as indicated in the summary table below. Clinic nurses reviewed the fracture history questionnaire with participants. History of reported clinical fractures was validated in a subset of 36%, with validation of 71% by medical chart review (1). Vertebral fractures identified by spine scans are included in the section on Bone and Osteoporosis Measures.