Children with Cystic Fibrosis May Benefit From Vitamin K Supplementation
NEW YORK (Reuters Health) Dec 05 - Patients with cystic fibrosis (CF) may need vitamin K supplementation of at least 1 mg/day to prevent complications related to low bone mineral density, Dutch investigators suggest. They found that CF patients tend to have low vitamin K levels and some indication of poor bone health.
Fat malabsorption increases the risk of vitamin K deficiency in CF, Dr. J. J. E. Hendriks and associates at the University Hospital Maastricht explain in the Archives of Disease in Childhood for November. This in turn affects bone mineral status, since vitamin K is a cofactor in carboxylation of glutamic acid and these compounds are found in osteocalcin as well as various clotting factors.
Because there is little consensus about treating vitamin K deficiency in CF, the authors compared vitamin K and bone mineral status in serum from 19 healthy subjects and 20 CF patients. Six patients were taking low-dose vitamin K (< 0.25 mg/day), and four were taking at least 1 mg/day.
They found that undercarboxylated osteocalcin and undercarboxylated prothrombin levels, markers of vitamin K status, were significantly higher in those receiving no or low-dose vitamin K supplementation than controls, whereas concentrations were lower in patients on high-dose vitamin K.
Because the opposite pattern was observed for carboxylated osteocalcin, "all other groups were vitamin K deficient to some degree," Dr. Hendriks' group suggests.
However, bone mineral markers were inconsistent in supporting their theory regarding improved bone health. Total osteocalcin, but not the bone-formation marker bone alkaline phosphatase, was significantly raised in the high-dose group. And for the bone resorption markers deoxypyridinoline and N-terminal collagen type 1, only the latter was lower in the high-dose vitamin K group.
Because the risk of pathological fractures will increase as CF patients survive longer, long-term randomized trials are required to clarify the association of vitamin K status with bone health, the investigators conclude.
Arch Dis Child 2003;
Reprinted with Permission
Brain Disorders/Neurological Index
