Correlations between insulin sensitivity and bone mineral density in non-diabetic men

Aims To investigate relationships between bone mineral density (BMD), insul in secretion and insulin sensitivity, controlling for body composition, in view of data suggesting that hypoglycaemia leads to decreased osteoblast pr oliferation and a negative calcium balance and that insulin stimulates oste oblast differentiation and collagen synthesis, with no clear evidence if th is response in impaired in insulin resistance. Methods Femur and whole body (WB) BMD was measured in 55 male patients with ischaemic heart disease and 40 healthy men, using a Hologic QDR-2000 densi tometer, Insulin sensitivity (S-i) was estimated as the rate of glucose dis appearance divided by the area under the insulin curve during an intravenou s glucose tolerance test. Results Insulin and C-peptide levels were not correlated with BMD, but S-i was a significant: predictor of femur (log, r = 0.35) and WB BMD (log r = 0 .29, both P < 0.01), even after controlling for weight: and age. Fat mass ( FM) was a predictor of BMD (femur: r = 0.33 P < 0.01, WB: r = 0.43 P < 0.00 1). In the femur the association with FM disappeared when log(S-i) was ente red in the regression. Lean body mass (LBM) contributed significantly to BM D (r = 0.50 and r = 0.66, both P < 0.001). Conclusions These results are compatible with a direct influence of lean bo dy mass on bone, while the impact of fat mass may consist of insulin resist ance with increased insulin exposure of bone. It is hypothesized that patie nts with insulin resistance in the metabolic pathway do not exhibit resista nce to the skeletal actions of insulin.