Vitamin K deficiency and osteopenia in disuse-affected limbs of vitamin D-deficient elderly stroke patients

Bone mineral density is reduced in stroke patients on the hemiplegic and co ntralateral sides, reflecting a degree of paralysis and vitamin D deficienc y. Because the deficiency of vitamin K, a factor essential for site-specifi c carboxylation of bone Cia protein, is also associated with reduced bone m ineral density, an additional contribution of vitamin K to bone changes was assessed in 168 elderly patients with long-standing post-stroke hemiplegia and hypovitaminosis D. Sera were analyzed to relate vitamin K-1 concentrat ions to bone-related biochemical indexes and bone mineral density measured by radiodensitometry of the second metacarpal. Bone mineral density was low er on both sides in patients than in the 56 controls (P < 0.02). Serum vita min K1 concentrations, which correlated positively with bone Cia protein co ncentrations (P < 0.0001), were lower in patients (0.48 +/- 0.47 nmol/L) th an controls (1.33 +/- 0.49; P < 0.0001). Serum bone cia protein and 25-hydr oxyvitamin D concentrations were lower in patients than controls (P < 0.000 1), whereas ionized Ca concentrations were higher in patients (1.277 +/- 0. 041 mmol/L) than controls (1.210 +/- 0.049; P < 0.0001), correlating with t he Barthel index. Multivariate linear regression identified vitamin K1, bon e Cia protein, 25-hydroxyvitamin D, ionized calcium, and the Barthel index as independent bone mineral density determinants on the hemiplegic side and 25-hydroxyvitamin D, calcium, and the Barthel index on the intact side. Im mobilization and vitamin K deficiency had stronger osteopenic effects on th e hemiplegic side than contralaterally.