Marjo H. J. Knapen, BSc; Karly Hamulyák, MD; Cees Vermeer, PhD
Study Objective: To determine whether vitamin K administration affects urinary calcium excretion in postmenopausal women.
Design: Before- and after-trials with a 2-week treatment period.
Subjects: Healthy postmenopausal women (55 to 75 years old) were recruited from the convents in and around Maastricht. Controls (25 to 40 years old) were healthy premenopausal volunteers.
Intervention: Daily administration of 1 mg of vitamin K for 2 weeks.
Measurements: Serum immunoreactive osteocalcin; hydroxylapatite binding (HAB) capacity of serum immunoreactive osteocalcin; excretion of calcium, hydroxyproline, and creatinine in the urine during the last 2 h of a 16-h fasting period.
Results: In premenopausal women, no effect of vitamin K administration was seen. In the postmenopausal group, vitamin K induced increased serum immunoreactive osteocalcin concentration; normalization of the HAB capacity of serum immunoreactive osteocalcin (this marker was less than 50% that of the controls in the pretreatment samples); a decrease in urinary calcium excretion, notably in the "fast losers" of calcium; and a parallel decrease in urinary hydroxyproline excretion in the fast losers of calcium.
Conclusions: The serum immunoreactive osteocalcin level may vary with vitamin K status. This variance should be taken into consideration if osteocalcin is used as a marker for osteoblast activity. Vitamin K is one factor that may play a role in the loss of bone mass in postmenopausal osteoporosis.
Knapen MHJ, Hamulyák K, Vermeer C. The Effect of Vitamin K Supplementation on Circulating Osteocalcin (Bone Gla Protein) and Urinary Calcium Excretion. Ann Intern Med. ;111:1001–1005. doi: 10.7326/0003-4819-111-12-1001
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Published: Ann Intern Med. 1989;111(12):1001-1005.
Endocrine and Metabolism, Metabolic Bone Disorders.
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