Assessment of fracture risk: value of random population-based samples--the Geelong Osteoporosis Study.
Fracture risk is determined by bone mineral density (BMD). The T-score, a measure of fracture risk, is the position of an individual's BMD in relation to a reference range. The aim of this study was to determine the magnitude of change in the T-score when different sampling techniques were used to produce the reference range. Reference ranges were derived from three samples, drawn from the same region: (1) an age-stratified population-based random sample, (2) unselected volunteers, and (3) a selected healthy subset of the population-based sample with no diseases or drugs known to affect bone. T-scores were calculated using the three reference ranges for a cohort of women who had sustained a fracture and as a group had a low mean BMD (ages 35-72 yr; n = 484). For most comparisons, the T-scores for the fracture cohort were more negative using the population reference range. The difference in T-scores reached 1.0 SD. The proportion of the fracture cohort classified as having osteoporosis at the spine was 26, 14, and 23% when the population, volunteer, and healthy reference ranges were applied, respectively. The use of inappropriate reference ranges results in substantial changes to T-scores and may lead to inappropriate management.
Henry
M J
MJ
The University of Melbourne, Department of Clinical and Biomedical Sciences, Geelong, Australia.
Pasco
J A
JA
Seeman
E
E
Nicholson
G C
GC
Sanders
K M
KM
Kotowicz
M A
MA
D015502:Absorptiometry, Photon / Q000592:standards*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications / Q000175:diagnosis*; D012016:Reference Values; D018570:Risk Assessment; D013048:Specimen Handling / Q000379:methods