BONE-MINERAL DENSITY IN THE FEMUR AND LUMBAR VERTEBRAE DECREASES AFTER 12 WEEKS OF DIABETES IN SPONTANEOUSLY DIABETIC-PRONE BB WORCESTER RATS/

The accumulated data indicate that bone mineral density (BMD) is decre ased in humans with insulin-dependent diabetes mellitus. The purpose o f this study was to prospectively determine sequential lumbar and femo ral BMD utilizing dual energy X-ray absorptiometry in rats that sponta neously become diabetic to determine if weight and blood glucose contr ol would prevent the diabetes-related bone mass changes. BMD of the lu mbar spine and femur was measured prior to the onset of diabetes and a t 3-week intervals after the diagnosis of diabetes for 12 weeks in 14 diabetes-prone BB/Wor rats (DR) and eight diabetes-resistant BB/ Wor c ontrol rats (DR). At 12 weeks, the lumbar (0.238 +/- 0.013 vs 0.262 +/ - 0.007 g/cm(2), P < 0.001) and femoral (0.313 +/- 0.013 vs 0.343 +/- 0.013 g/cm(2), P < 0.001) BMD were significantly lower in the DP rats despite significantly greater body weights (387 +/- 26 vs 329 +/- 46 g , P < 0.001) and plasma glucose levels of only 178 mg/dl. There was no difference in plasma values of calcium, phosphorus, osteocalcin, or t artrate-resistant acid phosphatase between groups or differences in os teoblast numbers in histologic sections. There was a significant (P < 0.001) decrease in plasma creatinine in the diabetic animals. The resu lts indicate that in; this animal model of type I diabetes, spine and femoral BMD do not increase comparable to control despite weight and b lood glucose control. This would suggest that the diabetic condition i tself affects bone mass in the absence of weight loss and poor blood g lucose control.