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 ß 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.

Effects of targeted therapies on bone in rheumatic and musculoskeletal diseases.

Generalized bone loss (osteoporosis) and fragility fractures can occur in rheumatic and musculoskeletal diseases including rheumatoid arthritis and spondyloarthritis (SpA; including ankylosing spondylitis and psoriatic arthritis). In addition, rheumatoid arthritis can involve localized, periarticular bone erosion and, in SpA, local (pathological) bone formation can occur. The RANK-RANKL-osteoprotegerin axis and the Wnt-ß-catenin signalling pathway (along with its inhibitors sclerostin and Dickkopf 1) have been implicated in inflammatory bone loss and formation, respectively. Targeted therapies including biologic DMARDs and Janus kinase (JAK) inhibitors can stabilize bone turnover and inhibit radiographic joint damage, and potentially also prevent generalized bone loss. Targeted therapies interfere at various points in the mechanisms of local and generalized bone changes in systemic rheumatic diseases, and they effect biomarkers of bone resorption and formation, bone mass and risk of fragility fractures. Studies on the effects of targeted therapies on rates of fragility fracture are scarce. The efficacy of biologic DMARDs for arresting bone formation in axial SpA is debated. Improved understanding of the most relevant therapeutic targets and identification of important targeted therapies could lead to the preservation of bone in inflammatory rheumatic and musculoskeletal diseases.

EDTA-Induced Pseudothrombocytopenia up to 9 Months after Initial COVID-19 Infection Associated with Persistent Anti-SARS-CoV-2 IgM/IgG Seropositivity.

Platelets have a role in vascular complications of COVID-19-related viral coagulopathy. Although immune-induced thrombocytopenia has been described mostly in moderate-to-severe COVID-19, the prognostic role of platelet count in COVID-19 is still controversial. Pseudothrombocytopenia has been reported to represent COVID-19-associated coagulopathy in critical illness, and transient EDTA-dependent pseudothrombocytopenia lasting less than 3 weeks was described in a patient with severe acute COVID-19 pneumonia. In our case study, EDTA-induced pseudothrombocytopenia was still present at 9 months after an initial SARS-CoV-2 virus infection in an apparently recovered 60 year old man. The persistence of antinucleocapside and antispike antibodies 9 months after the initial infection suggests that EDTA-induced pseudothrombocytopenia may be related to anti-SARS-CoV-2 IgG or IgM antibodies. We should acknowledge the possibility that pseudothrombocytopenia may also appear in some patients after seroconversion after the launch of large-scale vaccination programs.

Recommendations on the measurement and the clinical use of vitamin D metabolites and vitamin D binding protein - A position paper from the IFCC Committee on bone metabolism.

Vitamin D, an important hormone with a central role in calcium and phosphate homeostasis, is required for bone and muscle development as well as preservation of musculoskeletal function. The most abundant vitamin D metabolite is 25-hydroxyvitamin D [25(OH)D], which is currently considered the best marker to evaluate overall vitamin D status. 25(OH)D is therefore the most commonly measured metabolite in clinical practice. However, several other metabolites, although not broadly measured, are useful in certain clinical situations. Vitamin D and all its metabolites are circulating in blood bound to vitamin D binding protein, (VDBP). This highly polymorphic protein is not only the major transport protein which, along with albumin, binds over 99% of the circulating vitamin D metabolites, but also participates in the transport of the 25(OH)D into the cell via a megalin/cubilin complex. The accurate measurement of 25(OH)D has proved a difficult task. Although a reference method and standardization program are available for 25(OH)D, the other vitamin D metabolites still lack this. Interpretation of results, creation of clinical supplementation, and generation of therapeutic guidelines require not only accurate measurements of vitamin D metabolites, but also the accurate measurements of several other "molecules" related with bone metabolism. IFCC understood this priority and a committee has been established with the task to support and continue the standardization processes of vitamin D metabolites along with other bone-related biomarkers. In this review, we present the position of this IFCC Committee on Bone Metabolism on the latest developments concerning the measurement and standardization of vitamin D metabolites and its binding protein, as well as clinical indications for their measurement and interpretation of the results.

Analytical Performance Specifications for 25-Hydroxyvitamin D Examinations.

Currently the 25-hydroxy vitamin D (25(OH)D) concentration is thought to be the best estimate of the vitamin D status of an individual. Unfortunately, its measurement remains complex, despite recent technological advances. We evaluated the biological variation (BV) of 25(OH)D in order to set analytical performance specifications (APS) for measurement uncertainty (MU). Six European laboratories recruited 91 healthy participants. The 25(OH)D concentrations in K3-EDTA plasma were examined weekly for up to 10 weeks in duplicate on a Lumipulse G1200 (Fujirebio, Tokyo, Japan). The linear regression of the mean 25(OH)D concentrations at each blood collection showed that participants were not in a steady state. The dissection of the 10-sample collection into two subsets, namely collections 1-5 and 6-10, did not allow for correction of the lack of homogeneity: estimates of the within-subject BV ranged from 5.8% to 7.1% and the between-subject BV ranged from 25.0% to 39.2%. Methods that would differentiate a difference induced by 25(OH)D supplementation at p < 0.05 should have MU < 13.6%, while at p < 0.01, the MU should be <9.6%. The development of APS using BV assumes a steady state of patients. The findings in this study suggest that patients are not in steady state. Therefore, APS that are based on MU appear to be more appropriate.

The path to the standardization of PTH: Is this a realistic possibility? a position paper of the IFCC C-BM.

Parathyroid hormone (PTH) determination is of greatest importance for patients suffering from parathyroid gland disorders and for the follow-up of bone turnover in patients suffering from chronic kidney disease (CKD). Two generations of PTH assays are simultaneously present on the market for PTH quantification. As these assays are not yet standardized, this results in a significant level of confusion in the care of CKD patients. One key objective of the IFCC Committee for Bone Metabolism is to improve this situation. In this position paper, we will highlight the current state of PTH testing and propose a pathway to ultimately overcome issues resulting from PTH assay variability.

Analytical considerations and plans to standardize or harmonize assays for the reference bone turnover markers PINP and ß-CTX in blood.

Procollagen type I N-propeptide (PINP) and the C-terminal telopeptide of type I collagen (ß-CTX) in blood have been designated as reference bone turnover markers in osteoporosis by the International Osteoporosis Foundation (IOF) and International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). The IFCC Committee on Bone Metabolism (C-BM) has examined current commercial assays and performed a multicentre study to examine the agreement between assays for PINP and ß-CTX in serum and plasma. The results of these studies will inform our work towards the harmonization of PINP assays and the standardization of ß-CTX assays in blood, with the development of common calibrators and reference measurement procedures in collaboration with the reagent manufacturing industry. Successful achievement of these goals will help develop universally acceptable practice guidelines for the management of osteoporosis with the inclusion of common reference intervals and treatment targets for PINP and ß-CTX.

Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths.

The world is in the grip of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing the risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increasing concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced the risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D (25(OH)D) concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome; and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce the risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40-60 ng/mL (100-150 nmol/L). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.

Variations in 25-Hydroxyvitamin D in Countries from the Middle East and Europe: The Roles of UVB Exposure and Diet.

Serum 25-hydroxyvitamin D (25(OH)D) has been largely associated with latitude and sunshine exposure across several regions. According to previous results, 25(OH)D concentrations are, on average, relatively low in countries with abundant sunshine, including those of the Middle East and North Africa region, as well as lower-latitude Europe. The standard explanation for this phenomenon is that people wear concealing clothing because of cultural and religious practices and that high temperatures in summer limit direct sun exposure. However, the role of diet in the development of profound hypovitaminosis D has not been adequately explored in those countries. To examine how diet affects vitamin D status in the Middle Eastern and European countries, a search was conducted for papers from that region reporting 25(OH)D concentrations. Papers were sought that reported summertime and wintertime 25(OH)D concentrations for healthy nonpregnant adults representative of the entire population. Data from 15 Middle Eastern and European countries were found through this search. Data for postmenopausal women from 19 European countries were also obtained. Dietary supply data for animal products containing vitamin D (animal fat, eggs, ocean fish, animal meat, and milk) were obtained from the Food and Agriculture Organization of the United Nations. Latitude and a solar UVB dose index also were obtained for each country. For the 15-country study, energy from dietary factors was highly correlated with latitude, making it difficult to separate the effects of UVB exposure and dietary factors. However, for the 19-country study, dietary factors were only weakly correlated with latitude. In that study, ocean fish was the most important single dietary factor affecting serum 25(OH)D concentration for postmenopausal women in various European countries, but animal fat and meat also contributed. Because this is an ecological study, further research is encouraged to evaluate and extend the findings.

Vitamin D supplementation guidelines.

Research carried out during the past two-decades extended the understanding of actions of vitamin D, from regulating calcium and phosphate absorption and bone metabolism to many pleiotropic actions in organs and tissues in the body. Most observational and ecological studies report association of higher serum 25-hydroxyvitamin D [25(OH)D] concentrations with improved outcomes for several chronic, communicable and non-communicable diseases. Consequently, numerous agencies and scientific organizations have developed recommendations for vitamin D supplementation and guidance on optimal serum 25(OH)D concentrations. The bone-centric guidelines recommend a target 25(OH)D concentration of 20ng/mL (50nmol/L), and age-dependent daily vitamin D doses of 400-800IU. The guidelines focused on pleiotropic effects of vitamin D recommend a target 25(OH)D concentration of 30ng/mL (75nmol/L), and age-, body weight-, disease-status, and ethnicity dependent vitamin D doses ranging between 400 and 2000IU/day. The wise and balanced choice of the recommendations to follow depends on one's individual health outcome concerns, age, body weight, latitude of residence, dietary and cultural habits, making the regional or nationwide guidelines more applicable in clinical practice. While natural sources of vitamin D can raise 25(OH)D concentrations, relative to dietary preferences and latitude of residence, in the context of general population, these sources are regarded ineffective to maintain the year-round 25(OH)D concentrations in the range of 30-50ng/mL (75-125nmol/L). Vitamin D self-administration related adverse effects, such as hypercalcemia and hypercalciuria are rare, and usually result from taking extremely high doses of vitamin D for a prolonged time.

Why vitamin D clinical trials should be based on 25-hydroxyvitamin D concentrations.

Many health benefits are attributed to vitamin D, with those findings supported mostly by observational outcome studies of relationships to serum 25-hydroxyvitamin D [25(OH)D]. However, many randomized controlled trials (RCTs) aiming to confirm those findings have failed, perhaps because serum 25(OH)D is an index of UVB exposure and non-vitamin D mechanisms or because disease reduces serum 25(OH)D content. But the most likely reason for that failure is inappropriate design, conduct, analysis, and interpretation of RCTs. Most RCTs used principles designed to test pharmaceutical drugs; that design incorporates the assumptions that the RCT is the sole source of the agent and that dose-response relationships are linear. However, neither assumption is true for vitamin D, since neither vitamin D dose-responses or health outcome-serum 25(OH)D concentration relationships are linear-larger changes being induced with low rather than high baseline 25(OH)D values. Here, we propose a hybrid observational approach to vitamin D RCT design, based primarily on serum 25(OH)D concentration, requiring an understanding of serum 25(OH)D concentration-health outcome relationships, measuring baseline 25(OH)D values, recruiting non-replete subjects, measuring serum 25(OH)D during the trial for adjustment of supplemental doses for achievement of pretrial selection of target 25(OH)D values, where possible, and analyzing health outcomes in relation to those data rather than solely to vitamin D dosages.

Bone metabolism and the 10-year probability of hip fracture and a major osteoporotic fracture using the country-specific FRAX algorithm in men over 50 years of age with type 2 diabetes mellitus: a case-control study.

The aim of the study was to evaluate the 10-year probability of hip fracture and a major osteoporotic fracture using the FRAX algorithm, vitamin D status, bone mineral density (BMD), and biochemical markers of bone turnover in men over 50 years of age with type 2 diabetes mellitus (T2DM). We estimated FRAX-predicted 10-year fracture probability, levels of 25-hydroxyvitamin D (25-OH-D), markers of bone turnover, and bone mineral density at the L1-L4 (lumbar spine (LS)) and femur neck (FN) in 68 men with T2DM and compared these with an age-matched group (n = 68). The mean (range) age of the T2DM group was 61.4 (51-78) years. The prevalence of hypovitaminosis D (25-OH-D <75 nmol/L) was 59 %. The mean (range) FRAX hip fracture and FRAX major osteoporotic fracture was 0.7 (0-2.8) and 3.2 (0-8.5) %, respectively. BMD at the FN (0.974 vs. 0.915 g/cm(2), p = 0.008) and LS (1.221 vs. 1.068 g/cm(2), p < 0.001) was significantly higher in the T2DM cohort as compared to the healthy age-matched males. 25-OH-vitamin D (67.7 vs.79.8 nmol/L, p < 0.001), crosslaps (0.19 vs. 0.24 µg/L, p = 0.004), and osteocalcin (13.3 vs. 15.7 µg/L, p = 0.004) were significantly lower in the T2DM group. There was no difference in FRAX-related fracture probability between the two groups. Acknowledging the limitations of our study size, we suggest that the increased BMD in T2DM and the noninclusion of T2DM as a secondary risk factor in the FRAX algorithm may be probable explanations for the discordance between literature-observed and FRAX-related fracture probabilities.

Pre-malignant and malignant cervical pathologies among inert and copper-bearing intrauterine contraceptive device users: a 10-year follow-up study.

OBJECTIVES: The aim of the study was to compare the incidence of pre-malignant and malignant cervical conditions during a period of 10 years of use of inert (Szontagh) and copper-bearing IUCDs. METHODS: Candidates were parous women requesting intrauterine contraception regardless of the previous IUCD use and having no contraindications. Follow-ups were scheduled at 1, 6, and 12 months after insertion, and annually thereafter. Colposcopy and cytological evaluation were performed at insertion and at yearly follow-ups. For comparison of the two groups and the different follow-up periods (at the end of each ordinal year), net and gross cumulative lifetable rates were calculated. Statistical differences were measured by chi-squared test, and were regarded as significant at P

Ectopic pregnancy among non-medicated and copper-containing intrauterine device users: a 10-year follow-up.

OBJECTIVE: To compare ectopic pregnancy (EP) rates among users of non-medicated and copper-containing IUDs. STUDY DESIGN: The number of women with non-medicated and copper devices were 3491 and 11,682, respectively. Cumulative woman-months of use (CWMU), Pearl Index (PI) and gross cumulative lifetable EP rates for 1000 women were calculated. RESULTS: The numbers of users at the end of the 10th year were 550 and 569 for non-medicated and copper-containing IUDs, respectively. CWMU for plastic and copper devices was 191,678 and 473,533, respectively, at the 169th month of maximum follow-up. The PIs were 0.8 and 1.0 calculated for 1000 users per year. The gross cumulative lifetable EP rates for 1000 women were 1.4 and 0.9 at 12 months, and 6.8 and 8.9 at the end of the 10th year, respectively, for the plastic and the copper IUDs. CONCLUSION: Although the rates were lower for the plastic IUD in the majority of the observations, there were no statistically significant differences between the two groups.

The effects of pregnancy and lactation on hormonal status and biochemical markers of bone turnover.

INTRODUCTION: Biochemical markers of bone turnover are reliable indices for measuring changes in bone formation and bone resorption. Due to limitations in the use of bone densitometry during pregnancy biochemical markers of bone turnover provide an excellent alternative to examine the state of the skeleton during this physiologic state. STUDY DESIGN: We performed a prospective study in 20 women, during their first full term pregnancy until 12 months postpartum, intending to breast feed for 12 (mean, 9.1; range, 7-12) months postpartum. Morning blood and urine samples were obtained for laboratory tests: within 3 months before conception (baseline); between 22 and 24 gestational weeks; after delivery, and 6 and 12 months postpartum. Serum 25-hydroxyvitamin D (25-OH-D), parathyroid hormone (PTH), bone specific alkaline phosphatase, osteocalcin (OC), procollagen I carboxypeptides, calcium, phosphate and creatinine in addition to urine deoxypyridinoline crosslinks and calcium were measured. RESULTS: There was no significant difference in the values of urinary calcium/creatinine and serum calcium, phosphate and 25-OH-D between the different visits during the study. In our patients there was a significant increase in PTH levels at 12 months postpartum as compared to baseline, although the mean values remained in the PTH reference range. All bone turnover markers increased during pregnancy and failed to reach baseline level even 12 months postpartum. CONCLUSION: The high maternal bone turnover may suggest that the calcium needed for infant growth during pregnancy and lactation may be drawn at least in part from the maternal skeleton.

Pregnancy in women with systemic lupus erythematosus.

BACKGROUND: Systemic lupus erythematosus (SLE) is an autoimmune disorder which may be affected by hormonal changes, such as those of pregnancy. Women with SLE have increased adverse pregnancy outcomes. STUDY DESIGN: A retrospective analysis of the gynecologic and immunologic case history of 140 women with SLE and the outcome of 263 pregnancies in 99 women with SLE. RESULTS: In patients diagnosed with SLE, the proportion of pregnancies ending with live birth at term decreased to one-third compared with three quarters in those without a diagnosis of SLE and the incidence of pre-term deliveries and spontaneous abortions increased by 6.8 and 4.7 times, respectively. When SLE was associated with secondary antiphospholipid (APL) syndrome, and lupus anticoagulant (LA) or beta2-glycoprotein antibodies were present, a further increase in the incidence of pregnancy loss was observed. Pregnancy did not cause a flare-up of SLE in all cases, the disease remained stable in about 30% of the patients. Lupus was mild in the majority of the women who carried out their pregnancy to term. We also observed mothers with active SLE who successfully carried out pregnancies to term. CONCLUSION: These findings accord with previous literature and should inform rheumatologists, obstetricians and neonatologists who guide patients in their reproductive decisions.