Reference values for bone metabolism in a Japanese cohort survey randomly sampled from a basic elderly resident registry

Rapid bone microarchitecture decline in older men with high bone turnover-the prospective STRAMBO study

Older men with high bone turnover have faster bone loss. We assessed the link between the baseline levels of bone turnover markers (BTMs) and the prospectively assessed bone microarchitecture decline in men. In 825 men aged 60-87 yr, we measured the serum osteocalcin (OC), bone alkaline phosphatase (BAP), N-terminal propeptide of type I procollagen (PINP), and C-terminal telopeptide of type I collagen (CTX-I), and urinary total deoxypyridinoline (tDPD). Bone microarchitecture and strength (distal radius and distal tibia) were estimated by high-resolution pQCT (XtremeCT, Scanco Medical) at baseline and then after 4 and 8 yr. Thirty-seven men took medications affecting bone metabolism. Statistical models were adjusted for age and BMI. At the distal radius, the decrease in the total bone mineral density (Tt.BMD), cortical BMD (Ct.BMD), cortical thickness (Ct.Thd), and cortical area (Ct.Ar) and failure load was faster in the highest vs the lowest CTX-I quartile (failure load: -0.94 vs -0.31% yr-1, P < .001). Patterns were similar for distal tibia. At the distal tibia, bone decline (Tt.BMD, Ct.Thd, Ct.Ar, Ct.BMD, and failure load) was faster in the highest vs the lowest tDPD quartile. At each skeletal site, the rate of decrease in Tb.BMD differed between the extreme OC quartiles (P < .001). Men in the highest BAP quartile had a faster loss of Tt.BMD, Tb.BMD, reaction force, and failure load vs the lowest quartile. The link between PINP and bone decline was poor. The BTM score is the sum of the nos. of the quartiles for each BTM. Men in the highest quartile of the score had a faster loss of cortical bone and bone strength vs the lowest quartile. Thus, in the older men followed prospectively for 8 yr, the rate of decline in bone microarchitecture and estimated bone strength was 50%-215% greater in men with high bone turnover (highest quartile, CTX-I above the median) compared to the men with low bone turnover (lowest quartile, CTX-I below the median).

Biomarkers of aging

Aging biomarkers are a combination of biological parameters to (i) assess age-related changes, (ii) track the physiological aging process, and (iii) predict the transition into a pathological status. Although a broad spectrum of aging biomarkers has been developed, their potential uses and limitations remain poorly characterized. An immediate goal of biomarkers is to help us answer the following three fundamental questions in aging research: How old are we? Why do we get old? And how can we age slower? This review aims to address this need. Here, we summarize our current knowledge of biomarkers developed for cellular, organ, and organismal levels of aging, comprising six pillars: physiological characteristics, medical imaging, histological features, cellular alterations, molecular changes, and secretory factors. To fulfill all these requisites, we propose that aging biomarkers should qualify for being specific, systemic, and clinically relevant.

Practical Considerations for the Clinical Application of Bone Turnover Markers in Osteoporosis

Bone turnover markers (BTMs) are released during the bone remodelling cycle and are measurable in blood or urine, reflecting bone remodelling rate. They have been useful in elucidating the pharmacodynamics and effectiveness of osteoporosis medication in clinical trials and are increasingly used in routine clinical management of osteoporosis, especially for monitoring therapy, in addition to their use in other metabolic bone disease such as Paget's disease of bone and osteomalacia. Serum β isomerised C-terminal telopeptide of type I collagen and pro-collagen I N-terminal propeptide have been designated as reference BTMs for use in osteoporosis. In addition, bone-specific isoenzyme of alkaline phosphatase (B-ALP) secreted by osteoblasts and tartrate-resistant acid phosphatase 5b (TRACP-5b) secreted by osteoclasts are also found to be specific markers of bone formation and resorption, respectively. The concentrations of the latter enzymes in blood measured by immunoassay provide reliable measures of bone turnover even in the presence of renal failure. B-ALP is recommended for use in the assessment of renal bone disease of chronic kidney disease, and TRACP-5b shows promise as a marker of bone resorption in that condition. BTMs in blood do not suffer from biological variation to the same extent as the older BTMs that were measured in urine. Appropriate patient preparation and sample handling are important in obtaining accurate measures of BTMs for clinical use. Reference change values and treatment targets have been determined for the reference BTMs for their use in monitoring osteoporosis treatment. Further ongoing studies will enhance their clinical applications.

DXAGE 2.0 - adult age at death estimation using bone loss in the proximal femur and the second metacarpal

The accurate age at death assessment of unidentified adult skeletal individuals is a critical research task in forensic anthropology, being a key feature for the determination of biological profiles of individual skeletal remains. We have previously shown that the age-related decrease of bone mineral density (BMD) in the proximal femur could be used to assess age at death in women (Navega et al., J Forensic Sci 63:497-503, 2018). The present study aims to generate models for age estimation in both sexes through bone densitometry of the femur and radiogrammetry of the second metacarpal. The training sample comprised 224 adults (120 females, 104 males) from the "Coimbra Identified Skeletal Collection," and different models were generated through least squares regression and general regression neural networks (GRNN). The models were operationalized in a user-friendly online interface at https://osteomics.com/DXAGE2/ . The mean absolute difference between the known and estimated age at death ranges from 9.39 to 13.18 years among women and from 10.33 to 15.76 among men with the least squares regression models. For the GRNN models, the mean absolute difference between documented and projected age ranges from 8.44 to 12.58 years in women and from 10.56 to 16.18 years in men. DXAGE 2.0 enables age estimation in incomplete and/or fragmentary skeletal remains, using alternative skeletal regions, with reliable results.