Risedronate in Osteopenic Postmenopausal Women

The primary objective of this study is to compare risedronate 35 mg and placebo with respect to the percent change at 12 months for distal radius trabecular bone volume (BV/TV) in osteopenic postmenopausal women, as measured by three-dimensional peripheral quantitative computed tomography (3D pQCT). The secondary objectives are to compare the percent change from Screening/Baseline between the 2 treatment groups for the following measurements: * Bone mineral density of the lumbar spine, femoral neck, femoral trochanter, and total proximal femur using a dual energy X-ray absorptiometry (DXA) scan at 12 and 24 months; * 3D pQCT analysis of distal radius and distal tibia bone microarchitecture data at 6, 12, and 24 months; and * Bone turnover markers (BTMs) of: * fasting serum carboxyterminal cross linking telopeptide of type 1 bone collagen (CTX 1); * serum aminoterminal propeptide of type 1 procollagen (PINP); and * urine N-telopeptide cross-links (NTX) at 3, 6, 12, and 24 months.