title: Difference in the trajectory of change in bone geometry as measured by hip structural analysis in the narrow neck, intertrochanteric region, and femoral shaft between men and women following hip fracture.
abstract: Prior studies have shown that women have declines in bone structure and strength after hip fracture, but it is unclear whether men sustain similar changes. Therefore, the objective was to examine sex differences in proximal femur geometry following hip fracture. Hip structural analysis was used to derive metrics of bone structure and strength: aerial bone mineral density, cross-sectional bone area (CSA), cortical outer diameter, section modulus (SM), and buckling ratio (BR) from dual-energy x-ray absorptiometry scans performed at baseline (within 22days of hospital admission), two, six, or twelve months after hip fracture in men and women (n=282) enrolled in the Baltimore Hip Studies 7th cohort. Weighted estimating equations were used to evaluate sex differences at the narrow neck (NN), intertrochanteric (IT), and femoral shaft (FS). Men had significantly different one year NN changes compared to women in CSA: -6.33% (-12.47, -0.20) vs. 1.37% (-3.31, 6.43), P=0.049; SM: -4.98% (-11.08, 1.10) vs. 3.94% (-2.51, 10.42), P=0.042; and BR: 7.50% (0.65, 14.36) vs. -1.20% (-6.41, 4.00), P=0.044. One year IT changes displayed similar patterns, but the sex differences were not statistically significant for CSA: -4.07% (-10.83, 2.67) vs. 0.41% (-3.41, 4.24), P=0.252; SM: -4.78% (-12.10, 5.53) vs. -0.31 (-4.74, 4.11), P=0.287; and BR: 4.59% (-0.65, 9.84) vs. 1.52% (-4.23, 7.28), P=0.425. Differences in FS geometric parameters were even smaller in magnitude and not significantly different by sex. Women generally experienced non-significant increases in bone tissue and strength following hip fracture, while men had structural declines that were statistically greater at the NN region. Reductions in the mechanical strength of the proximal femur after hip fracture could put men at higher risk for subsequent fractures of the contralateral hip.
authors: University of Maryland School of Medicine, Baltimore, MD, United States. Electronic address: arathbun@epi.umaryland.edu.
authors: Alan M
authors: AM
authors: Rathbun
authors: National Institutes on Aging, Baltimore, MD, United States.
authors: Michelle
authors: M
authors: Shardell
authors: University of Maryland School of Medicine, Baltimore, MD, United States.
authors: Denise
authors: D
authors: Orwig
authors: University of Maryland School of Medicine, Baltimore, MD, United States.
authors: J Richard
authors: JR
authors: Hebel
authors: University of Delaware, Newark, DE, United States.
authors: Gregory E
authors: GE
authors: Hicks
authors: Beck Radiological Innovations, Catonsville, MD, United States.
authors: Thomas J
authors: TJ
authors: Beck
authors: University of Maryland School of Medicine, Baltimore, MD, United States.
authors: Jay
authors: J
authors: Magaziner
authors: University of Maryland School of Medicine, Baltimore, MD, United States.
authors: Marc C
authors: MC
authors: Hochberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology; D005272:Femur Neck / Q000000981:diagnostic imaging* / Q000502:physiology; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000502:physiology; D006801:Humans; D008297:Male; D012727:Sex Characteristics
keywords: Aging; DXA; Fracture prevention; Injury/fracture healing; Osteoporosis