Association Between Insulin Resistance and Bone Mass in Men

Context: The association between insulin resistance and bone mass is still not clear. Objective: The purpose of this study was to evaluate the association between insulin resistance and bone mass. Design and Setting: This was a cross-sectional survey of the nationally representative population. Participants: A total of 3113 men (aged >= 20 years) from the fourth Korean National Health and Nutrition Examination Survey of 2008-2009 were included. Main Outcome Measures: Bone mineral density (BMD) was measured using dual-energy x-ray absorptiometry. Osteopenia and osteoporosis were defined using the World Health Organization T score criteria. Fasting plasma insulin and glucose levels were measured, and insulin resistance was evaluated using the homeostasis model assessment-estimated insulin resistance (HOMA-IR) index. Results: Age-, height-, and weight-adjusted mean BMD values significantly decreased as quartiles of HOMA-IR and the fasting plasma insulin level increased (P for trends <.001). In multivariable logistic regression analyses, participants who had a higher HOMA-IR or fasting plasma insulin level had a higher odds ratio for osteoporosis/osteopenia. Interestingly, the association between fasting plasma insulin level and whole-body BMD differed by the degree of insulin resistance. In the lowest quartile of HOMA-IR, the fasting insulin level was positively associated with BMD. As insulin resistance increased, however, the fasting insulin level was inversely associated with BMD, and this relationship became more significant as the degree of insulin resistance increased. Conclusions: In a nationally representative sample of Korean men, insulin resistance and the fasting plasma insulin level were inversely associated with bone mass. Further studies are required to confirm this association and reveal the underlying mechanisms.