A bone structural basis for fracture risk in diabetes.
BACKGROUND
Elevated areal bone mineral density (aBMD) in type 2 diabetes mellitus is inconsistent with increased fracture risk at some skeletal sites.


OBJECTIVE
Because aBMD is an imperfect surrogate for bone strength, we assessed bone structure and strength more directly using quantitative computed tomography.


METHODS
Diabetic and nondiabetic subjects were evaluated in a cross-sectional study.


METHODS
Subjects were recruited from a random sample of the Rochester, MN, population.


METHODS
Forty-nine subjects (28 women and 21 men) with type 2 diabetes were compared with age- and sex-matched nondiabetic controls.


METHODS
We measured bone geometry, strength, and volumetric BMD (vBMD) at the hip, spine, and wrist, along with hip aBMD, using central and peripheral quantitative computed tomography and estimated bone load to bone strength ratios at each site.


RESULTS
Adjusted for differences in body mass index between cases and controls (29.8 vs. 27.6), hip aBMD was greater in diabetic subjects, but this was accounted for by greater trabecular vBMD. Cortical vBMD was similar in the two groups, as was bone cross-sectional area and cortical thickness. Bone strength measures were generally better in diabetic subjects, but bone loads were higher from their greater weight. Consequently, load to strength ratios (i.e. factor-of-risk) were similar.


CONCLUSIONS
Patients with type 2 diabetes enjoy little benefit from elevated aBMD in terms of improved bone load to strength ratios. With no deficit in bone density, the rationale for antiresorptive therapy in diabetic patients is uncertain, but potential adverse effects of diabetes on bone quality need more study.
Melton
L Joseph
LJ
Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905, USA. melton.j@mayo.edu
Riggs
B Lawrence
BL
Leibson
Cynthia L
CL
Achenbach
Sara J
SJ
Camp
Jon J
JJ
Bouxsein
Mary L
ML
Atkinson
Elizabeth J
EJ
Robb
Richard A
RA
Khosla
Sundeep
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology; D001842:Bone and Bones / Q000473:pathology; D003430:Cross-Sectional Studies; D048909:Diabetes Complications / Q000473:pathology*; D003924:Diabetes Mellitus, Type 2 / Q000473:pathology*; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D012306:Risk; D012727:Sex Characteristics; D014057:Tomography, X-Ray Computed; D055815:Young Adult
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