Vitamin K and maintenance of skeletal integrity in adults.

PURPOSE

To determine the role of vitamin K status in the maintenance of skeletal integrity in adults.

PATIENTS AND METHODS

1. Bone mineral density (BMD) was measured by quantitative digital radiography (QDR) in 50 patients taking a vitamin K antagonist (warfarin) who were recruited from a large urban cardiology practice, and 50 age-, sex- and race-matched controls recruited from the community. 2. The relationship of BMD versus indices of vitamin K status (determined by measuring levels of vitamin K and descarboxyprothrombin in the plasma) in 113 nonanticoagulated adults was assessed.

RESULTS

Measurements of BMD in the hip and spine were similar in anticoagulated subjects and matched controls. Multivariate analysis revealed that use of warfarin was not associated with a lower BMD. Ninety-five percent confidence intervals excluded a 0.06 g/cm2 reduction in BMD associated with the use of warfarin. Indices of vitamin K status did not correlate with BMD in normal subjects.

CONCLUSIONS

Patients receiving long-term maintenance therapy with a vitamin K antagonist have normal bone density. BMD is unrelated to vitamin K status in nonanticoagulated subjects. These data suggest that vitamin K does not have a major role in maintenance of skeletal integrity in adults.