Change in hip bone mineral density and risk of subsequent fractures in older men.
Low bone mineral density (BMD) increases fracture risk; how changes in BMD influence fracture risk in older men is uncertain. BMD was assessed at two to three time points over 4.6 years using dual-energy X-ray absorptiometry (DXA) for 4470 men aged ≥65 years in the Osteoporotic Fractures in Men (MrOS) Study. Change in femoral neck BMD was estimated using mixed effects linear regression models. BMD change was categorized as "accelerated" (≤-0.034 g/cm(2) ), "expected" (between 0 and -0.034 g/cm(2) ), or "maintained" (≥0 g/cm(2) ). Fractures were adjudicated by central medical record review. Multivariate proportional hazards models estimated the risk of hip, nonspine/nonhip, and nonspine fracture over 4.5 years after the final BMD measure, during which time 371 (8.3%) men experienced at least one nonspine fracture, including 78 (1.7%) hip fractures. Men with accelerated femoral neck BMD loss had an increased risk of nonspine (hazard ratio [HR] = 2.0; 95% confidence interval [CI] 1.4-2.8); nonspine/nonhip (HR = 1.6; 95% CI 1.1-2.3); and hip fracture (HR = 6.3; 95% CI 2.7-14.8) compared with men who maintained BMD over time. No difference in risk was seen for men with expected loss. Adjustment for the initial BMD measure did not alter the results. Adjustment for the final BMD measure attenuated the change in BMD-nonspine fracture and the change in BMD-nonspine/nonhip relationships such that they were no longer significant, whereas the change in the BMD-hip fracture relationship was attenuated (HR = 2.6; 95% CI 1.1-6.4). Total hip BMD change produced similar results. Accelerated decrease in BMD is a strong, independent risk factor for hip and other nonspine fractures in men.
Research Institute, California Pacific Medical Center, San Francisco, CA, USA. pcawthon@sfcc-cpmc.net
Peggy M
PM
Cawthon
Susan K
SK
Ewing
Dawn C
DC
Mackey
Howard A
HA
Fink
Steven R
SR
Cummings
Kristine E
KE
Ensrud
Marcia L
ML
Stefanick
Doug C
DC
Bauer
Jane A
JA
Cauley
Eric S
ES
Orwoll
D000368:Aged; D015519:Bone Density / Q000502:physiology*; D016001:Confidence Intervals; D004198:Disease Susceptibility; D005272:Femur Neck / Q000503:physiopathology; D006615:Hip / Q000502:physiology / Q000503:physiopathology*; D006620:Hip Fractures / Q000453:epidemiology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D016103:Spinal Fractures / Q000503:physiopathology; D014481:United States / Q000453:epidemiology