Biochemical Markers of Bone Turnover and Prediction of Hip Bone Loss in Older Women: The Study of Osteoporotic Fractures

Abstract

To examine the ability of commercially available biochemical markers of bone formation and resorption to predict hip bone loss, we prospectively obtained serum and timed 2-h urine specimens from 295 women age 67 years or older who were not receiving estrogen replacement therapy. Serum was assayed for two markers of bone formation: osteocalcin (OC) and bone-specific alkaline phosphatase (BALP). Urine specimens were assayed for four markers of bone resorption: N-telopeptides (NTX), free pyridinolines (Pyr), free deoxypyridinoline (Dpyr), and C-telopeptides (CTX). Measurements of hip bone mineral density were made at the time the samples were collected and then repeated an average of 3.8 years later. Higher levels of all four resorption markers were, on average, significantly associated with faster rates of bone loss at the total hip, but not at the femoral neck. Women with OC levels above the median had a significantly faster rate of bone loss than women with levels below the median, but there was no significant association between levels of BALP and hip bone loss. The sensitivity and specificity of higher marker levels for predicting rapid hip bone loss was limited, and there was considerable overlap in bone loss rates between women with high and low marker levels. We conclude that higher levels of urine NTX, CTX, Pyr, Dpyr, and serum OC are associated with faster bone loss at the hip in this population of elderly women not receiving estrogen replacement therapy, but these biochemical markers have limited value for predicting rapid hip bone loss in

Enhanced bone metabolism in vegetarians – the role of vitamin B12 deficiency

“…Since animal products are a good source of vitamin D and vitamin B12, a vegetarian diet might be associated with depletion of both vitamin B12 and vitamin D stores; the latter being of major importance for bone health. Increased bone turnover with aging is associated with accelerated bone loss (30)(31)(32)(33)(34).…”

Perspective: On Genetic Studies of Bone Loss

“…Also, although bone turnover markers may be useful for predicting bone loss rate in some circumstances, (7) the sensitivity and specificity of the predictions are very limited. (8) In addition, the heritability of bone turnover markers is still controversial.(9,10) Thus, no studies have powerfully addressed the important question of whether the rate of bone loss is heritable.Second, the rate of bone loss may be influenced by multiple environmental and physiological factors, such as age, (11) body composition, (12) and skeletal sites.(13) Lack of controlling these important factors may lead to adverse effects on genetic studies of bone loss. Notably, the variation of bone loss rate can never be independent of the variation of BMD.…”

A moderately high intake compared to a low intake of zinc depresses magnesium balance and alters indices of bone turnover in postmenopausal women

“…The highest value for plasma osteocalcin was found when the women fed the low dietary copper consumed deficient dietary zinc. This could be considered unfavorable because an increased concentration of serum total osteocalcin has been associated with increased hip bone loss in humans (Bauer, 2001) and with suppressed bone formation and stimulated bone resorption in rats (Tanimoto et al, 1991). High dietary zinc tended to increase bone-specific alkaline phosphatase, especially in the women fed low dietary copper.…”