Low vitamin K status is associated with low BMD and increased fracture risk. Additionally, a specific menaquinone, menatetrenone (MK4), may reduce fracture risk. However, whether vitamin K plays a role in the skeletal health of North American women remains unclear. Moreover, various K vitamers (e.g., phylloquinone and MK4) may have differing skeletal effects. The objective of this study was to evaluate the impact of phylloquinone or MK4 treatment on markers of skeletal turnover and BMD in nonosteoporotic, postmenopausal, North American women. In this double-blind, placebo-controlled study, 381 postmenopausal women received phylloquinone (1 mg daily), MK4 (45 mg daily), or placebo for 12 mo. All participants received daily calcium and vitamin D 3 supplementation. Serum bone-specific alkaline phosphatase (BSALP) and n-telopeptide of type 1 collagen (NTX) were measured at baseline and 1, 3, 6, and 12 mo. Lumbar spine and proximal femur BMD and proximal femur geometry were measured by DXA at baseline and 6 and 12 mo. At baseline, the three treatment groups did not differ in demographics or study endpoints. Compliance with calcium, phylloquinone, and MK4 treatment was 93%, 93%, and 87%, respectively. Phylloquinone and MK4 treatment reduced serum undercarboxylated osteocalcin but did not alter BSALP or NTX. No effect of phylloquinone or MK4 on lumbar spine or proximal femur BMD or proximal femur geometric parameters was observed. This study does not support a role for vitamin K supplementation in osteoporosis prevention among healthy, postmenopausal, North American women receiving calcium and vitamin D supplementation.

This study assessed bone mineral density (BMD) comparability and precision using Lunar Prodigy and iDXA densitometers (GE Healthcare, Madison, WI) in adults. Additionally, the utility of supine forearm measurement with iDXA was investigated. Lumbar spine and bilateral proximal femur measurements were obtained in routine clinical manner in 345 volunteers, 202 women and 143 men of mean age 52.5 (range: 20.1–91.6) yr. Seated and supine distal forearm scans were obtained in a subset (n = 50). Lumbar spine and proximal femur precision assessments were performed on each instrument following International Society for Clinical Densitometry recommendations in 30 postmenopausal women. BMD at the L1–L4 spine, total proximal femur, and femoral neck was very highly correlated (r2 ≥ 0.98) between densitometers, as was the one-third radius site (r2 5 0.96). Bland-Altman analyses demonstrated no clinically significant bias at all evaluated sites. BMD precision was similar between instruments at the L1–L4 spine, mean total proximal femur, and femoral neck. Finally, one-third radius BMD measurements in the supine vs seated position on the iDXA were highly correlated (r2 = 0.96). In conclusion, there is excellent BMD correlation between iDXA and Prodigy densitometers. Similarly, BMD precision is comparable with these two instruments.

We studied reproducibility of the ISCD vertebral exclusion criteria among four interpreters. Surprisingly, agreement among interpreters was only moderate, because of differences in threshold for diagnosing focal structural defects and choice of which vertebra among a pair discordant for T-score, area, or BMC to exclude. Our results suggest that reproducibility may be improved by specifically addressing the sources of interobserver disagreement.Introduction: Although DXA is widely used to measure vertebral BMD, its interpretation is subject to multiple confounders including osteoarthritis, aortic calcification, and scoliosis. In an attempt to standardize interpretation and minimize the impact of artifacts, the International Society for Clinical Densitometry (ISCD) established criteria for vertebral exclusion, including the presence of a focal structural defect (FSD), discrepancy of >1 SD in T-score between adjacent vertebrae, and a lack of increase in BMC or area from L 1 to L 4 . Whereas the efforts of the ISCD represent an important advance in BMD interpretation, the interobserver reproducibility with application of these criteria is unknown. We hypothesized that there would be substantial agreement among four interpreters regarding application of the exclusion criteria and the final lumbar spine T-score. Materials and Methods: Each interpreter read a set of 200 lumbar DXA scans obtained on male veterans, applying the ISCD vertebral body exclusion criteria. Results: Surprisingly, agreement among interpreters was only moderate. Differences in interpretation resulted from differing thresholds for recognition of FSD and the choice of excluding the upper or lower vertebral body for the criteria requiring comparison between adjacent vertebrae. Conclusions: Despite their apparent simplicity, the ISCD vertebral exclusion criteria are difficult to apply consistently. In principle, appropriate refinement of the exclusion criteria may significantly improve interobserver agreement.

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