Effect of changes in serum levels of endogenous hydrogen sulfide on fracture healing: Study protocol clinical trial (SPIRIT compliant).

BACKGROUND: Fracture is a common disease; many factors affect fracture healing. Recent studies have confirmed that hydrogen sulfide (H2S) plays an essential role in bone formation, but most of these studies are drawing conclusions based on animal experiment; whether H2S could promote fracture healing in patients is still unclear. We aim to investigate the change of serum H2S in fracture patients, and analyze its effort on fracture healing. METHODS: This is a single-center, prospective cohort study. Patients with spinal or limb fracture will be recruited. Patient's serum and urine will be collected at baseline for examination (serum H2S, ß-CTX, OC, PINP, 25-OH-VitD3, S-CTX, urinary calcium, and urinary creatinine). All patients will be followed-up for 24 months in outpatients settings, the image of X-ray or CT will be reviewed and fracture healing will be judged by 2 experienced orthopedic physicians. The difference in serum parameters especially H2S will be compared between patients with fracture healed within 9 months and those with fracture unhealed at 9 months. DISCUSSION: Results of the trial could provide insight into influence of H2S on fracture healing. ETHICS AND DISSEMINATION: The study was approved by the ethics committee of School of Medicine UESTC & Sichuan Provincial People's Hospital Ethics Committee. All the participants will be asked to provide written informed consent before data collection. The findings of the study will be published in peer-reviewed journals and will be presented at national or international conferences.

Hyperparathyroidism in patients over 75: Clinical characteristics and outcome. Is conservative treatment a safe alternative?

OBJECTIVE: With the current aging of the world's population, primary hyperparathyroidism (PHPT) is increasingly detected in the elderly. Yet data on the presentation and outcome of PHPT in this group are scarce. The objective was to describe a cohort of patients aged 75 years or more with PHPT observed in our endocrine clinic. STUDY DESIGN: A retrospective analysis of medical records in an endocrine clinic at a tertiary hospital. We evaluated 182 patients with PHPT, aged 75 years or more at their last follow-up, all diagnosed at age 65 or more. Laboratory data were compared at diagnosis and last follow-up. RESULTS: Mean age at diagnosis was 73 ± 4 years, last follow-up was at 83 ± 4 years, and mean follow-up was 11.3 ± 5.5 years. Osteoporosis, fractures, and nephrolithiasis were diagnosed in 114(63 %), 84(46 %), and 43(24 %) patients, respectively. Overall, 150 patients had an indication for surgery; of them, the 29 who underwent parathyroidectomy were younger than the non-operated patients and had higher rates of hypercalciuria. During the follow-up of the 141 patients who did not undergo operation, serum and urinary calcium levels significantly had decreased, and vitamin D level had increased at last visit (10.4 ± 0.5 mg/dl, 161 ± 70 mg/24 h, 69 ± 17 nmol/l, p < 0.01 respectively) compared with levels at diagnosis (10.6 ± 0.2 mg/dl, 223 ± 95 mg/24 h, 53 ± 15 nmol/l, respectively, p = 0.001). Overall, 38 of the 182 patients (20 %) died during follow-up; these patients were significantly older at diagnosis (76 ± 5 vs. 72 ± 4 years) but there were no differences in laboratory variables. CONCLUSIONS: While most patients had a formal indication for surgery, few underwent parathyroidectomy. Serum and urinary calcium significantly decreased during follow-up in patients who did not undergo surgery. Our data are reassuring and support at least the consideration of conservative treatment for these patients.

Proteinuria Is Associated With Increased Risk of Fragility Fracture in Men With or at Risk of HIV Infection.

BACKGROUND: Proteinuria has been associated with bone loss and fractures in general population, but data in HIV-infected population are lacking. SETTING: Prospective, multicenter cohort study of men with or at risk of HIV infection. METHODS: Between 2006 and 2015, urine protein measurements and bone fracture histories were ascertained semiannually in 947 HIV-infected (HIV+) and 969 HIV-uninfected (HIV-) men aged 40 years or older. Proteinuria was defined as protein-to-creatinine ratio ≥200 mg/g at ≥2 consecutive visits. Outcome measures (1) all fractures (excluding fractures of skull, face, and digits) and (2) fragility fractures (fractures of vertebral column, femur, wrist, and humerus). Multivariable Cox proportional hazards models assessed the association between proteinuria and fracture after adjusting for additional risk factors. RESULTS: The overall period prevalence of proteinuria was higher among HIV+ than HIV- (29% vs 6%, P < 0.001). Men with proteinuria had a significantly higher risk of fragility fracture compared with men without proteinuria [adjusted hazard ratio (aHR) = 2.29 (1.12-4.66)] and did not differ by HIV serostatus (p-interaction = 0.83). The risk of all fractures was not statistically different between men with or without proteinuria [aHR = 1.31 (0.84-2.05)]. Among HIV+ men, the association between confirmed proteinuria and fragility fracture was attenuated [aHR = 2.12 (0.95-4.73)] after additional adjustment for CD4 T-cell count/mm, history of AIDS, the presence of detectable plasma HIV-1 RNA, and cumulative exposure to tenofovir disoproxil fumarate. CONCLUSIONS: Proteinuria was more common in HIV+ than in HIV- men and was a strong independent risk factor for fragility fracture regardless of HIV serostatus. Proteinuria should prompt consideration of a thorough evaluation for bone disease among HIV+ persons.

The variation in urinary calcium levels in adult patients with fracture and surgical intervention.

BACKGROUND: Generally, a higher calcium diet is fed to fracture patients after surgery. However, recent studies have indicated that higher dietary calcium intakes increase the risk of urinary stones for fracture patients. Therefore, this study aimed to observe the variation in urinary calcium levels among fracture patients who underwent surgery, based on fracture type, fracture location, age and gender. METHODS: A total of 768 subjects were enrolled in this study from 2012 to 2015 and were divided into 2 groups: group A (fracture patients who underwent surgery) and group B (normal patients without fracture). Urine samples were collected for a 24-h period (24-h urine), at multiple specific time points before and after surgery for group A, or after hospitalisation for group B. Subsequently, urine calcium was detected and the changes were evaluated according to fracture location, fracture type, age and gender, as well as the distribution of hypercalciuria. RESULTS: Compared with group B, the level of urine calcium in group A significantly increased at different time points during the study period (P < 0.05). There were significant differences in the changes in urine calcium levels according to fracture location, fracture type and age, but not gender. Further, there were more patients with hypercalciuria in group A at the different time points, compared with group B. CONCLUSION: Variation in urinary calcium among fracture patients that underwent surgery was of a regular pattern and hypercalciuria was also found in these patients. Therefore, a high-calcium diet and calcium supplements should be used with caution in this patient population.

Association of Increased Urinary Albumin With Risk of Incident Clinical Fracture and Rate of Hip Bone Loss: the Osteoporotic Fractures in Men Study.

Prior studies suggest that increased urine albumin is associated with a heightened fracture risk in women, but results in men are unclear. We used data from Osteoporotic Fractures in Men (MrOS), a prospective cohort study of community-dwelling men aged ≥65 years, to evaluate the association of increased urine albumin with subsequent fractures and annualized rate of hip bone loss. We calculated albumin/creatinine ratio (ACR) from urine collected at the 2003-2005 visit. Subsequent clinical fractures were ascertained from triannual questionnaires and centrally adjudicated by review of radiographic reports. Total hip BMD was measured by DXA at the 2003-2005 visit and again an average of 3.5 years later. We estimated risk of incident clinical fracture using Cox proportional hazards models, and annualized BMD change using ANCOVA. Of 2982 men with calculable ACR, 9.4% had ACR ≥30 mg/g (albuminuria) and 1.0% had ACR ≥300 mg/g (macroalbuminuria). During a mean of 8.7 years of follow-up, 20.0% of men had an incident clinical fracture. In multivariate-adjusted models, neither higher ACR quintile (p for trend 0.75) nor albuminuria (HR versus no albuminuria, 0.89; 95% CI, 0.65 to 1.20) was associated with increased risk of incident clinical fracture. Increased urine albumin had a borderline significant, multivariate-adjusted, positive association with rate of total hip bone loss when modeled in ACR quintiles (p = 0.06), but not when modeled as albuminuria versus no albuminuria. Macroalbuminuria was associated with a higher rate of annualized hip bone loss compared to no albuminuria (-1.8% more annualized loss than in men with ACR <30 mg/g; p < 0.001), but the limited prevalence of macroalbuminuria precluded reliable estimates of its fracture associations. In these community-dwelling older men, we found no association between urine albumin levels and risk of incident clinical fracture, but found a borderline significant, positive association with rate of hip bone loss. © 2016 American Society for Bone and Mineral Research.

Urinary Citrate, an Index of Acid-Base Status, Predicts Bone Strength in Youths and Fracture Risk in Adult Females.

CONTEXT: Diet can impact on bone strength via metabolic shifts in acid-base status. In contrast to the strongly diet-dependent biomarker urinary potential renal acid load (uPRAL), the amount of renally excreted citrate integrates nutritional and systemic influences on acid-base homeostasis with high citrate indicating prevailing alkalization. OBJECTIVE: To examine the association between urinary citrate excretion and bone strength as well as long-term fracture risk. DESIGN AND PARTICIPANTS: Prospective cross-sectional analysis; 231 healthy children (6-18 y) of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study were included, with at least 2 urine collections available during the 4 years preceding peripheral quantitative computed tomography (pQCT) of the nondominant proximal forearm. uPRAL, urinary citrate, and urinary nitrogen excretion were quantified in 857 24-hour urine samples. Data on overall fracture incidence were collected within a 15-year follow-up after pQCT measurement. MAIN OUTCOME MEASURES: Parameters of bone quality and geometry (pQCT) as well as long-term fracture incidence. RESULTS: After controlling for confounders, especially forearm length, muscle area, and urinary nitrogen (biomarker of protein intake), urinary citrate excretion was positively associated with various parameters of bone quality and geometry (P < .05). Fracture risk in adult females, but not in males, was inversely associated with urinary citrate and positively with uPRAL (P < .05). CONCLUSIONS: Although urinary citrate has to be confirmed as an integrated noninvasive biomarker of systemic acid-base status in further studies, our results substantiate dietary and metabolic acidity as potentially adverse for bone health in the long run from childhood onward.

Low-Level Cadmium Exposure Is Associated With Decreased Bone Mineral Density and Increased Risk of Incident Fractures in Elderly Men: The MrOS Sweden Study.

One risk factor for osteoporosis that has attracted increasing attention in recent years is exposure to cadmium. The aim of this study was to examine the associations between low-level cadmium exposure, from diet and smoking, and bone mineral density (BMD) and incident fractures in elderly men. The study population consisted of 936 men from the Swedish cohort of the Osteoporotic Fractures in Men (MrOS) study, aged 70 to 81 years at inclusion (years 2002 to 2004), with reliable data on cadmium in urine (U-Cd) analyzed using inductively coupled plasma mass spectrometry in baseline samples. The participants also answered a questionnaire on lifestyle factors and medical history. BMD was measured at baseline using dual-energy X-ray absorptiometry (DXA) in the total body, hip, and lumbar spine. During the follow-up period (until 2013), all new fractures were registered by date and type. Associations between BMD and U-Cd were assessed using multiple linear regression, and associations between incident fractures and baseline U-Cd were analyzed using Cox regression. In both cases, a number of potential confounders and other risk factors (eg, age, smoking, body mass index [BMI], and physical activity) were included in the models. We found significant negative associations between U-Cd and BMD, with lower BMD (4% to 8%) for all sites in the fourth quartile of U-Cd, using the first quartile as the reference. In addition, we found positive associations between U-Cd and incident fractures, especially nonvertebral osteoporosis fractures in the fourth quartile of U-Cd, with hazard ratios of 1.8 to 3.3 in the various models. U-Cd as a continuous variable was significantly associated with nonvertebral osteoporosis fractures (adjusted hazard ratio 1.3 to 1.4 per µg Cd/g creatinine), also in never-smokers, but not with the other fracture groups (all fractures, hip fractures, vertebral fractures, and other fractures). Our results indicate that even relatively low cadmium exposure through diet and smoking increases the risk of low BMD and osteoporosis-related fractures in elderly men.

Methylation of bone SOST, its mRNA, and serum sclerostin levels correlate strongly with fracture risk in postmenopausal women.

Inhibition of sclerostin, a glycoprotein secreted by osteocytes, offers a new therapeutic paradigm for treatment of osteoporosis (OP) through its critical role as Wnt/catenin signaling regulator. This study describes the epigenetic regulation of SOST expression in bone biopsies of postmenopausal women. We correlated serum sclerostin to bone mineral density (BMD), fractures, and bone remodeling parameters, and related these findings to epigenetic and genetic disease mechanisms. Serum sclerostin and bone remodeling biomarkers were measured in two postmenopausal groups: healthy (BMD T-score > -1) and established OP (BMD T-score < -2.5, with at least one low-energy fracture). Bone specimens were used to analyze SOST mRNAs, single nucleotide polymorphisms (SNPs), and DNA methylation changes. The SOST gene promoter region showed increased CpG methylation in OP patients (n = 4) compared to age and body mass index (BMI) balanced controls (n = 4) (80.5% versus 63.2%, p = 0.0001) with replication in independent cohorts (n = 27 and n = 36, respectively). Serum sclerostin and bone SOST mRNA expression correlated positively with age-adjusted and BMI-adjusted total hip BMD (r = 0.47 and r = 0.43, respectively; both p < 0.0005), and inversely to serum bone turnover markers. Five SNPs, one of which replicates in an independent population-based genomewide association study (GWAS), showed association with serum sclerostin or SOST mRNA levels under an additive model (p = 0.0016 to 0.0079). Genetic and epigenetic changes in SOST influence its bone mRNA expression and serum sclerostin levels in postmenopausal women. The observations suggest that increased SOST promoter methylation seen in OP is a compensatory counteracting mechanism, which lowers serum sclerostin concentrations and reduces inhibition of Wnt signaling in an attempt to promote bone formation.

Bone resorption and fracture across the menopausal transition: the Study of Women's Health Across the Nation.

OBJECTIVE: Bone turnover markers (BTMs) predict fracture in older women, whereas data on younger women are lacking. To test the hypothesis that BTMs measured before and after menopause predict fracture risk, we performed a cohort study of 2,305 women. METHODS: Women attended up to nine clinic visits for an average of 7.6 ± 1.6 years; all were aged 42 to 52 years and were premenopausal or early perimenopausal at baseline. Incident fractures were self-reported. Serum osteocalcin and urinary cross-linked N-telopeptide of type I collagen (NTX) were measured at baseline. NTX was measured at each annual follow-up. Interval-censored survival models or generalized estimating equations were used to test whether baseline BTMs and changes in NTX, respectively, were associated with fracture risk. Hazard ratios (HRs) or odds ratios were calculated with 95% CIs. RESULTS: Women who experienced fractures (n = 184) had about a 10% higher baseline median NTX (34.4 vs 31.5 nanomoles of bone collagen equivalents per liter per nanomole of creatinine per liter; P = 0.001), but there was no difference in osteocalcin. A 1-SD decrease in lumbar spine bone mineral density (BMD) measured premenopausally was associated with a higher fracture risk during menopause (HR, 1.50; 95% CI, 1.28-1.68). Women with a baseline NTX greater than the median had a 45% higher risk of fracture, multivariable-adjusted (HR, 1.46; 95% CI, 1.05-2.26). The HR of fracture among women with both the lowest spine BMD (quartile 1) and the highest NTX (quartile 4) at baseline was 2.87 (95% CI, 1.61-6.01), compared with women with lower NTX and higher BMD. Women whose NTX increased more than the median had a higher risk of fracture (odds ratio, 1.51; 95% CI, 1.08-2.10). Women who had baseline NTX greater than the median experienced greater loss of spine and hip BMD. CONCLUSIONS: A higher urinary NTX excretion measured before menopause and across menopause is associated with a higher risk of fracture. Our results are consistent with the pathophysiology of transmenopausal changes in bone strength.

Long-term cadmium exposure and the association with bone mineral density and fractures in a population-based study among women.

All people are exposed to cadmium (Cd) via food; smokers are additionally exposed. High Cd exposure is associated with severe bone damage, but the public health impact in relation to osteoporosis and fractures at low environmental exposure remains to be clarified. Within the population-based Swedish Mammography Cohort, we assessed urinary Cd [U-Cd, µg/g of creatinine (cr)] as a marker of lifetime exposure and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) among 2688 women. Register-based information on fractures was retrieved from 1997 to 2009. Associations were evaluated by multivariable regression analyses. In linear regression, U-Cd was inversely associated with BMD at the total body (p < .001), femoral neck (p = .025), total hip (p = .004), lumbar spine (p = .088), and volumetric femoral neck (p = .013). In comparison with women with U-Cd < 0.50 µg/g of cr, those with U-Cd ≥ 0.75 µg/g of cr had odds ratios (ORs) of 2.45 [95% confidence interval (CI) 1.51-3.97] and 1.97 (95% CI 1.24-3.14) for osteoporosis at the femoral neck and lumbar spine, respectively. Among never-smokers, the corresponding ORs were 3.47 (95% CI 1.46-8.23) and 3.26 (95% CI 1.44-7.38). For any first fracture (n = 395), the OR was 1.16 (95% CI 0.89-1.50) comparing U-Cd ≥ 0.50 µg/g of cr with lower levels. Among never-smokers, the ORs (95% CIs) were 2.03 (1.33-3.09) for any first fracture, 2.06 (1.28-3.32) for first osteoporotic fracture, 2.18 (1.20-3.94) for first distal forearm fracture, and 1.89 (1.25-2.85) for multiple incident fractures. U-Cd at low environmental exposure from food in a general population of women showed modest but significant association with both BMD and fractures, especially in never-smokers, indicating a larger concern than previously known.

Urinary pentosidine and plasma homocysteine levels at baseline predict future fractures in osteoporosis patients under bisphosphonate treatment.

To clarify what kind of risk factors predict incident fractures in patients treated with bisphosphonates, the authors investigated the relationship between baseline characteristics and incident vertebral fracture in Japanese osteoporosis patients undergoing bisphosphonate treatment. This was a multi-center follow-up study conducted at three centers, in which a total of 251 Japanese patients with osteoporosis (mean age 70.5 years) from the three centers were followed for 3.2 ± 2.0 years. Baseline data, including pre-existing fractures, bone mineral density in the lumbar spine (LBMD), bone metabolic markers, urinary pentosidine, and plasma homocysteine, were evaluated. Changes in LBMD, bone turnover markers, and incident fractures after the treatment were followed. Sixty-one patients developed incident vertebral fractures; this group of patients was older and had lower LBMD, a higher prevalent vertebral fracture number, and higher homocysteine and pentosidine levels than patients who did not develop incident vertebral fractures. Changes in LBMD, urinary N-terminal telopeptides of type I collagen (NTX), and bone-derived alkaline phosphatase showed no significant association with the occurrence of vertebral fractures. Cox's proportional hazard model demonstrated that age, prevalent fracture, pentosidine, and homocysteine were independent predictors of the incident vertebral fracture rate under bisphosphonate treatment. Higher baseline levels of pentosidine and homocysteine in osteoporosis patients are potential risk factors for incident vertebral fractures when these patients are treated with bisphosphonates. Further clarification is needed to explain why such patients have higher fracture susceptibility.

Low urine pH and acid excretion do not predict bone fractures or the loss of bone mineral density: a prospective cohort study.

BACKGROUND: The acid-ash hypothesis, the alkaline diet, and related products are marketed to the general public. Websites, lay literature, and direct mail marketing encourage people to measure their urine pH to assess their health status and their risk of osteoporosis.The objectives of this study were to determine whether 1) low urine pH, or 2) acid excretion in urine [sulfate + chloride + 1.8x phosphate + organic acids] minus [sodium + potassium + 2x calcium + 2x magnesium mEq] in fasting morning urine predict: a) fragility fractures; and b) five-year change of bone mineral density (BMD) in adults. DESIGN: Cohort study: the prospective population-based Canadian Multicentre Osteoporosis Study. Multiple logistic regression was used to examine associations between acid excretion (urine pH and urine acid excretion) in fasting morning with the incidence of fractures (6804 person years). Multiple linear regression was used to examine associations between acid excretion with changes in BMD over 5-years at three sites: lumbar spine, femoral neck, and total hip (n = 651). Potential confounders controlled included: age, gender, family history of osteoporosis, physical activity, smoking, calcium intake, vitamin D status, estrogen status, medications, renal function, urine creatinine, body mass index, and change of body mass index. RESULTS: There were no associations between either urine pH or acid excretion and either the incidence of fractures or change of BMD after adjustment for confounders. CONCLUSION: Urine pH and urine acid excretion do not predict osteoporosis risk.

Pentosidine and increased fracture risk in older adults with type 2 diabetes.

CONTEXT: Type 2 diabetes is associated with higher fracture risk at a given bone mineral density. Advanced glycation endproducts (AGEs) accumulate in bone collagen with age and diabetes and may weaken bone. OBJECTIVE: The aim was to determine whether urine pentosidine, an AGE, was associated with fractures in older adults with and without diabetes. DESIGN: We performed an observational cohort study. SETTING: We used data from the Health, Aging and Body Composition prospective study of white and black, well-functioning men and women ages 70-79 yr. PARTICIPANTS: Participants with (n = 501) and without (n = 427) diabetes were matched on gender, race, and study site. PREDICTOR: Urine pentosidine was assayed from frozen stored baseline specimens. MAIN OUTCOME MEASURES: Incident clinical fractures and baseline vertebral fractures were measured. RESULTS: Despite higher bone mineral density, clinical fracture incidence (14.8 vs. 12.6%) and vertebral fracture prevalence (2.3 vs. 2.9%) were not lower in those with diabetes (P > 0.05). In multivariable models, pentosidine was associated with increased clinical fracture incidence in those with diabetes [relative hazard, 1.42; 95% confidence interval (CI), 1.10, 1.83, for 1 sd increase in log pentosidine] but not in those without diabetes (relative hazard, 1.08; 95% CI, 0.79, 1.49; P value for interaction = 0.030). In those with diabetes, pentosidine was associated with increased vertebral fracture prevalence (adjusted odds ratio, 5.93; 95% CI, 2.08, 16.94, for 1 sd increase in log pentosidine) but not in those without diabetes (adjusted odds ratio, 0.74; 95% CI, 0.30, 1.83; P value for interaction = 0.005). CONCLUSIONS: Higher pentosidine levels are a risk factor for fracture in older adults with diabetes and may account in part for reduced bone strength in type 2 diabetes.

High bone turnover is associated with accelerated bone loss but not with increased fracture risk in men aged 50 and over: the prospective MINOS study.

OBJECTIVES: The association of bone turnover markers (BTM) with bone loss and fracture risk in men is poorly studied. The morphological basis of such a relationship is unknown. The objective of this study was to evaluate the association between baseline BTM levels and subsequent bone loss and fracture risk in men. METHODS: This study is a prospective 7.5-year follow-up of the cohort composed of 723 men aged 50-85 years. Serum concentrations of osteocalcin, bone alkaline phosphatase (BAP), procollagen type I N-terminal propeptide, C-terminal telopeptide of type I collagen (beta-CTX-I) and urinary excretion of deoxypyridinoline and beta-CTX-I were measured at baseline. Every 18 months, incident fractures were recorded and bone mineral density (BMD) was measured by dual energy x ray absorptiometry DXA (spine, hip, distal forearm, whole body). RESULTS: Increase in BTM levels was associated with faster bone loss at the level of the trochanter, whole body and distal forearm. At the level of the distal radius and the ulna, increase in the serum BAP and beta-CTX-I levels were associated with faster apparent, net and estimated endosteal bone mineral loss. BTM levels did not correlate with the periosteal expansion rate. BTMs were significantly associated with bone mineral loss but their predictive power was poor. BTMs did not predict incident fractures. CONCLUSIONS: In men aged 50 and over, accelerated bone turnover is associated with greater endosteal bone mineral loss. From a practical point of view, BTMs cannot be used for the prediction of accelerated bone loss or fractures in the clinical management of osteoporosis in men.

Effect of fracture on bone turnover markers: a longitudinal study comparing marker levels before and after injury in 113 elderly women.

UNLABELLED: In this longitudinal, prospective, and population-based study (n = 1044), seven BTMs were assessed before and after trauma in 113 elderly women (85 with fractures). Markers were not altered in the immediate postfracture period but were clearly elevated during fracture repair. Recent fracture should thus be taken into account when markers are used in clinical practice. INTRODUCTION: Fracture may influence the levels of bone turnover markers (BTM) and have implications for their use in clinical practice. In this longitudinal, prospective, and population-based study, we assessed prefracture levels of BTMs and compared them with postfracture levels of the same individuals immediately after fracture and during fracture repair. This is the first study in which the effect of fracture on bone markers has been evaluated with prefracture samples available. MATERIALS AND METHODS: Serum and urine were collected at the emergency unit from 85 women (77.9 +/- 1.8 yr) who sustained a fracture after low-energy trauma and 28 controls (77.8 +/- 2.0 yr) with similar trauma but no fracture. All were participants of the Malmö OPRA study (n = 1044), and pretrauma samples were collected 1.05 +/- 0.85 yr before. Bone turnover was assessed by seven different BTMs reflecting different stages of bone metabolism {C-terminal cross-linked telopeptides of type I collagen [S-CTX], S-TRACP5b, N-terminal propeptides of type I collagen [S-PINP], serum osteocalcin (S-OC[1-49] and S-TotalOC), urinary deoxypyridinoline [U-DPD], and urinary osteocalcin [U-OC]}. RESULTS: BTMs sampled within a few hours after fracture were not altered from preinjury levels. Both bone formation and bone resorption markers were, however, significantly increased 4 mo after fracture. The elevation was most pronounced after hip fracture. Bone turnover remained elevated up to 12 mo after fracture. CONCLUSIONS: We believe this study extends our knowledge on the skeletal postfracture metabolic processes. In addition, it may provide a basis for future means to monitor pharmacological intervention promoting fracture healing.

Vitamin K deficiency from long-term warfarin anticoagulation does not alter skeletal status in male rhesus monkeys.

UNLABELLED: Vitamin K (K) inadequacy may cause bone loss. Thus, K deficiency induced by anticoagulants (e.g., warfarin) may be an osteoporosis risk factor. The skeletal impact of long-term warfarin anticoagulation was evaluated in male monkeys. No effect on BMD or bone markers of skeletal turnover was observed. This study suggests that warfarin-induced K deficiency does not have skeletal effects. INTRODUCTION: The skeletal role of vitamin K (K) remains unclear. It is reasonable that a potential role of vitamin K in bone health could be elucidated by study of patients receiving oral anticoagulants that act to produce vitamin K deficiency. However, some, but not all, reports find K deficiency induced by warfarin (W) anticoagulation to be associated with low bone mass. Additionally, epidemiologic studies have found W use to be associated with either increased or no change in fracture risk. Such divergent results may imply that human studies are compromised by the physical illnesses for which W was prescribed. MATERIALS AND METHODS: To remove this potential confounder, we prospectively assessed skeletal status during long-term W anticoagulation of healthy nonhuman primates. Twenty adult (age, 7.4-17.9 yr, mean, 11.7 yr) male rhesus monkeys (Macaca mulatta) were randomized to daily W treatment or control groups. Bone mass of the total body, lumbar spine, and distal and central radius was determined by DXA at baseline and after 3, 6, 9, 12, 18, 24, and 30 mo of W treatment. Serum chemistries, urinary calcium excretion, bone-specific alkaline phosphatase, and total and percent unbound osteocalcin were measured at the same time-points. Prothrombin time and international normalized ratio (INR) were monitored monthly. Serum 25-hydroxyvitamin D was measured at the time of study conclusion. RESULTS: W treatment produced skeletal K deficiency documented by elevation of circulating undercarboxylated osteocalcin (8.3% W versus 0.4% control, p<0.0001) but did not alter serum markers of skeletal turnover, urinary calcium excretion, or BMD. CONCLUSIONS: In male rhesus monkeys, long-term W anticoagulation does not alter serum markers of bone turnover or BMD. Long-term W therapy does not have adverse skeletal consequences in primates with high intakes of calcium and vitamin D.

An update on biomarkers of bone turnover and their utility in biomedical research and clinical practice.

BACKGROUND: Maintenance of the structural and functional integrity of the skeleton is a critical function of a continuous remodeling driven by highly associated processes of bone resorption and synthetic activities driven by osteoclasts and osteoblasts, respectively. Acceleration of bone turnover, accompanied with a disruption of the coupling between these cellular activities, plays an established role in the pathogenesis of metabolic bone diseases, such as osteoporosis. During the past decades, major efforts have been dedicated to the development and clinical assessment of biochemical markers that can reflect the rate of bone turnover. Numerous studies have provided evidence that serum levels or urinary excretion of these biomarkers correlate with the rate of bone loss and fracture risk, proving them as useful tools for improving identification of high-risk patients. OBJECTIVE: The aim of the present review is to give an update on biomarkers of bone turnover and give an overview of their applications in epidemiological and clinical research. DISCUSSION: Special attention is given to their utility in clinical trials testing the efficacy of drugs for the treatment of osteoporosis and how they supplement bone mass measurements. Recent evidence suggests that biochemical markers may provide information on bone age that may have indirectly relates to bone quality; the latter is receiving increasing attention. A more targeted use of biomarkers could further optimize identification of high-risk patients, the process of drug discovery, and monitoring of the efficacy of osteoporosis treatment in clinical settings.

Urine cartilage oligomeric matrix protein (COMP) measurement is useful in discriminating the osteoarthritic Thoroughbreds.

OBJECTIVE: To quantify the urinary concentration of cartilage oligomeric matrix protein (COMP), and to evaluate the relationship between urinary COMP concentration and the catabolic activity of synovial fluid (SF) in diseased horses. METHODS: COMP in horse urine was detected by immunoblotting with a monoclonal antibody (mAb; 14G4) raised against equine COMP from articular cartilage. Urine and serum samples were obtained from 83 Thoroughbred horses with aseptic joint diseases (AJD, 79 horses) or septic joint diseases (SJD, four horses) at the time of anesthesia induction, and samples of SF were obtained during surgery. Control samples of urine (n=111) were collected from normal horses free of any orthopedic diseases after they had been racing. COMP concentration was determined in all samples using inhibition enzyme-linked immunosorbent assay (ELISA) with mAb 14G4. SF samples were also used for the quantification of gelatinase activity. RESULTS: Positive bands of COMP fragments were determined on the immunoblots with mAb 14G4. The urinary COMP concentrations in AJD and SJD horses (1.02+/-0.75 and 1.55+/-1.17 microg/100mg creatinine, respectively) were significantly higher than normal (0.57+/-0.29 microg/100mg creatinine). In 55 horses with fractures in the AJD group there was a logarithmic relationship (r=-0.45, P<0.001) between the urinary and SF COMP measurements, while the urinary COMP level was positively correlated with matrix metalloproteinase (MMP)-2 and -9 activities (r=0.30, P<0.05 and r=0.51, P<0.001, respectively) in SF. CONCLUSIONS: The urinary COMP assay with mAb 14G4 is useful for discriminating horses with osteoarthritis. The higher COMP levels in urine from such horses would be indicative of enhanced proteolytic activity, in addition to the increased COMP levels in the diseased joints.

Urinary excretion of type I collagen cross-linked N-telopeptide and serum bone-specific alkaline phosphatase analysis to determine the correlation of age and back-pain related changes in elderly women.

We evaluated bone turnover using biochemical markers in 273 women over 60 years of age with suspected osteoporosis. Their age range was 60-96 years, with an average of 72.7 years. Patients with disorders that might affect bone metabolism were excluded. Those complaining of back pain within 6 months before or after examination were assigned to the back-pain group. Serum bone-specific alkaline phosphatase (BAP) was measured as a bone formation marker, and the urinary N-terminal telopeptide of type I collagen (NTX) was measured as a bone resorption marker. Both BAP and NTX levels increased in individuals over 60 years of age; moreover, these markers were significantly higher in subjects aged over 80 years. Among elderly patients, both BAP and NTX levels were significantly higher in those with back pain than in those without, and in a similar way were observed to increase in parallel with age from the 60-year point. We found that both NTX and BAP increased with aging, and that the increase in these bone turnover markers was closely related to back pain. We also showed that NTX and BAP levels increased significantly in women over 80 years, and specifically in patients with back pain.

Interaction between environmental tobacco smoke and arsenic methylation ability on the risk of bladder cancer.

OBJECTIVE: Arsenic exposure and environmental tobacco smoke (ETS) have been suspected to be associated with bladder cancer risk. We hypothesize that interaction between ETS and the ability to methylate arsenic, a detoxification pathway, modifies the risk of bladder cancer. METHODS: From January 1996 to December 1999, we identified 41 newly diagnosed bladder cancer patients and 202 fracture and cataract patients at the National Cheng-Kung University (NCKU) Medical Center. The levels of urinary arsenic species [As(III), As(V), MMA(V), and DMA(V)] were determined in all subjects. RESULTS: We found significant interaction between ETS and secondary methylation index (SMI) on the risk of bladder cancer (p=0.02). Among non-smokers with a high primary methylation index (PMI), the risk of bladder cancer was lower in subjects exposed to ETS (OR, 0.37; 95% CI, 0.14-0.96) than in subjects without exposure to ETS. Among non-smokers without ETS, the risk of bladder cancer was 4.7 times higher in subjects with a low SMI (95% CI, 1.30-16.81) than in subjects with a high SMI. CONCLUSIONS: Ability to methylate arsenic plays an important role in reducing the risk of bladder cancer attributable to the continuation of arsenic exposure from drinking water and from ETS exposure.