<p class="first" id="P1">Older adults with type 2 diabetes (T2D) tend to have normal
or greater areal bone
mineral density (aBMD), as measured by DXA, than those who do not have diabetes (non-T2D).
Yet, risk of fracture is higher in T2D, including 40%–50% increased hip fracture risk.
We used HR-pQCT to investigate structural mechanisms underlying skeletal fragility
in T2D. We compared cortical and trabecular bone microarchitecture, density, bone
area, and strength in T2D and non-T2D. In secondary analyses we evaluated whether
associations between T2D and bone measures differed according to prior fracture, sex,
and obesity.
</p><p id="P2">Participants included 1,069 members of the Framingham Study, who attended
examinations
2005–2008 and underwent HR-pQCT scanning in 2012–2015. Mean age was 64 (±8) years
(range, 40–87), and 12% (n=129) had T2D. After adjustment for age, sex, weight, and
height, T2D had lower cortical vBMD (p<0.01), higher cortical porosity (p=0.02),
and
smaller cross-sectional area (p=0.04) at the tibia, but not radius. Trabecular indices
were similar or more favorable in T2D than non-T2D. Associations between T2D and bone
measures did not differ according to sex or obesity status (all interaction p>0.05),
however associations did differ in those with a prior fracture and those with no history
of fracture. Specifically, cortical vBMD at the tibia and cortical thickness at the
radius were lower in T2D than non-T2D, but only among those individuals with a prior
fracture. Cortical porosity at the radius was higher in T2D than non-T2D, but only
among those who did not have a prior fracture.
</p><p id="P3">Findings from this large, community-based study of older adults suggest
that modest
deterioration in cortical bone and reductions in bone area may characterize diabetic
bone disease in older adults. Evaluation of these deficits as predictors of fracture
in T2D is needed to develop prevention strategies in this rapidly increasing population
of older adults.
</p>