Small bone size, greater volumetric bone mineral density and mostly favorable bone microarchitecture at both weight and non-weight-bearing skeletal sites were found among postmenopausal women without diabetes.
Vikram V. Shanbhogue, MD, of the department of endocrinology at Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, and colleagues evaluated data from the SWAN study on 146 postmenopausal women (mean age, 60.3 years) without diabetes to determine the effect of insulin resistance on peripheral bone geometry, volumetric BMD, bone microarchitecture and estimated bone strength.
Bone density and microstructure at the distal radius and tibia were assessed by high-resolution peripheral quantitative CT. Homeostasis model assessment for insulin resistance (HOMA-IR) was used to estimate fasting insulin and glucose; greater insulin resistance was indicated by higher values.
Participants were divided into two groups based on HOMA-IR quartiles; high HOMA-IR included the top two quartiles and low HOMA-IR included the bottom two quartiles.
Compared with the low HOMA-IR group, the high HOMA-IR group had greater areal BMD at the total hip (P = .001) and lumbar spine (P = .011), higher ratio of cortical to total bone area at the radius (P = .011) and tibia (P = .002), higher total volumetric BMD at the radius and tibia (P < .001 for both), higher cortical thickness at the radius and tibia (P < .02 for both), lower cortical porosity at the tibia (P = .001), greater trabecular number at the radius (P < .05) and larger trabecular thickness at the radius (P < .05) and tibia (P < .05).
The high HOMA-IR group had greater estimates of bone stiffness and failure load at both sites compared with the low HOMA-IR group (P < .001 for all).
“Data from our study indicate that the presence of peripheral insulin resistance and hyperinsulinemia have a generally favorable outcome on bone density and microarchitecture independent of body size in healthy, nondiabetic postmenopausal women,” the researchers wrote. “These results suggest the possibility that bone cells may remain sensitive to the actions of insulin in conditions of peripheral insulin resistance, although further experimental studies at the bone tissue and cellular levels are needed to confirm this notion.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.