Serum and urine markers of type I collagen metabolism in elderly women with high and low bone mineral density

The serum markers of bone formation (carboxy-terminal propeptide of type I collagen, PICP) and resorption (pyridinoline cross-links containing telopeptide of type I collagen, ICTP), as well as urinary resorption markers, pyridinoline (Pyr) and deoxypyridinoline (Dpyr), were studied in 78-year-old women with high (n = 18) and low (n = 17) bone mineral density (BMD) measured from the calcaneus and tibia. The low-BMD group had higher values for PICP (P = 0.025), Pyr (P = 0.001) and Dpyr (P < 0.001) than the high-BMD group. No inverse relationship between these markers and BMD was, however, observed within the study groups. ICTP, Pyr and Dpyr correlated with each other in both groups and with PICP in the high-BMD group. Higher levels of both the formation and resorption markers of type I collagen suggest an increased rate of bone turnover and remodelling in osteopenic elderly women.