Reference intervals of biochemical bone turnover markers for Saudi Arabian women: a cross-sectional study

Bone turnover markers reference database in five Southeast Asian countries

Osteoporosis is highly prevalent, particularly in developing countries. However, bone turnover marker reference ranges for management of osteoporosis in Asian population are yet to be explored and established. Thus, this study aims to develop a regional bone turnover markers (BTMs) reference database by combining country-specific reference database from five ASEAN countries: Malaysia, the Philippines, Singapore, Thailand, and Vietnam. We established a healthy reference population of 746 healthy premenopausal women aged 20 to 44 years old. Serum Procollagen 1 N-Terminal Propeptide (P1NP), Osteocalcin (OC), and Beta-Crosslaps (CTX) concentrations were measured using an automated immunoassay analyzer system, the cobas® modular analyzer systems (Roche Diagnostic Gmbh). The reference interval was defined as the central 95 % range. The estimated reference interval for CTX was 128 to 811 ng/L, OC was 9.0 to 33.0 μg/L, and for P1NP, the range was 22.8 to 96.5 μg/L. Comparison across countries showed that Singaporeans had the highest levels of median CTX along with Thais and Filipinos, who had significantly higher levels of P1NP and OC. Exploratory analysis on the associations with age showed that BTMs decreased with increasing age at 20 to 29 years old and plateaued after 30 years old. When excluding participants in their 20s, the reference interval estimated were CTX: 117-678 ng/L, P1NP: 21.6-85.8 μg/L and OC: 3.5-27.0 μg/L respectively. To the best of our knowledge, this is the first study to report BTMs reference intervals based on a healthy premenopausal Southeast Asian population which will contribute to the appropriate assessment and monitoring of bone turnover rate in the evaluation and management of osteoporosis in the Southeast Asian region. LAY SUMMARY: Osteoporosis is a common health issue, especially in developing countries. However, there is a lack of information on bone health markers specific to the Southeast Asian population. This study aimed to fill this gap by creating a reference database for bone turnover markers (BTMs) in Southeast Asian countries, including Malaysia, the Philippines, Singapore, Thailand, and Vietnam. The researchers studied 746 healthy women aged 20 to 44 years and measured blood markers related to bone health. The reference interval, representing the normal range, was determined. For example, the normal range for CTX was found to be 128 to 811 ng/L, for Osteocalcin was 9.0 to 33.0 μg/L, and for P1NP, the range was 22.8 to 96.5 μg/L. When excluding participants in their 20s, the reference intervals estimated were CTX: 117-678 ng/L, P1NP: 21.6-85.8 μg/L and OC: 3.5-27.0 μg/L respectively. Comparing the results across countries, Singaporeans, Thais, and Filipinos showed variations in their biochemical bone marker levels. Additionally, the study observed changes in the levels with age, with a decrease in BTMs observed after the age of 30. This groundbreaking study provides the first-ever reference intervals for BTMs in a healthy premenopausal Southeast Asian population. These findings will help in the proper assessment and monitoring of bone health, contributing to the management of osteoporosis in the Southeast Asian region.

Changes in Collagen Type I C-Telopeptide and Procollagen Type I N-Terminal Propeptide During the Menopause Transition

CONTEXT

Collagen type I C-telopeptide (CTX) and procollagen type I N-terminal propeptide (PINP) are reference bone resorption and formation markers, respectively.

OBJECTIVE

To characterize CTX and PINP trajectories across the menopause transition (MT).

METHODS

This 18-year longitudinal analysis of a community-based cohort from the Study of Women's Health Across the Nation included 541 women (126 Black, 90 Chinese, 87 Japanese, 238 White) who transitioned from pre- to postmenopause. Multivariable mixed effects regression fit piecewise linear models of CTX or PINP relative to years from final menstrual period (FMP); covariates were race/ethnicity, body mass index (BMI), and age at FMP. In the referent participant (White, 52.46 years at FMP, BMI 27.12 kg/m2), CTX and PINP were stable until 3 years pre-FMP (premenopause). During the MT (3 years before to 3 years after the FMP), CTX and PINP increased 10.3% (P < .0001) and 7.5% (P < .0001) per year, respectively; MT-related gains totaled 61.9% for CTX and 45.2% for PINP. Starting 3 years post-FMP (postmenopause), CTX and PINP decreased 3.1% (P < .0001) and 2.9% (P < .0001) per year, respectively. Compared with the White participants, during the MT, Chinese participants had larger gains in CTX (P = .01), and Japanese women experienced greater increases in CTX (P < .0001) and PINP (P = .02). In postmenopause, CTX (P = .01) and PINP (P = .01) rose more in Japanese relative to White women.

CONCLUSION

CTX and PINP are stable in premenopause, increase during the MT, and decrease in postmenopause. During the MT and postmenopause, bone turnover change rates vary by race/ethnicity.

Bone Turnover Markers: Basic Biology to Clinical Applications

Bone turnover markers (BTMs) are used widely, in both research and clinical practice. In the last 20 years, much experience has been gained in measurement and interpretation of these markers, which include commonly used bone formation markers bone alkaline phosphatase, osteocalcin, and procollagen I N-propeptide; and commonly used resorption markers serum C-telopeptides of type I collagen, urinary N-telopeptides of type I collagen and tartrate resistant acid phosphatase type 5b. BTMs are usually measured by enzyme-linked immunosorbent assay or automated immunoassay. Sources contributing to BTM variability include uncontrollable components (e.g., age, gender, ethnicity) and controllable components, particularly relating to collection conditions (e.g., fasting/feeding state, and timing relative to circadian rhythms, menstrual cycling, and exercise). Pregnancy, season, drugs, and recent fracture(s) can also affect BTMs. BTMs correlate with other methods of assessing bone turnover, such as bone biopsies and radiotracer kinetics; and can usefully contribute to diagnosis and management of several diseases such as osteoporosis, osteomalacia, Paget's disease, fibrous dysplasia, hypophosphatasia, primary hyperparathyroidism, and chronic kidney disease-mineral bone disorder.

Associations between biomarkers of matrix metabolism and inflammation with pain and fatigue in participants suspected of early hip and or knee osteoarthritis: data from the CHECK study

OBJECTIVES

To assess the associations of biomarkers in serum [highsensitivity C-reactive protein (hs-CRP), serum cartilage oligomeric protein (sCOMP), serum propeptide of type I procollagen (sPINP) and serum osteocalcin (sOC)] and urine [urinary type II collagen telopeptide (uCTX-2)] with the extent and progression of nocturnal pain, pain while walking, and fatigue in participants with hip and/or knee pain suspected to be early stage osteoarthritis (OA).

METHODS

hs-CRP, uCTX-2, sCOMP, sPINP and sOC were measured at baseline in 1,002 participants of the Cohort Hip and Cohort Knee (CHECK). Nocturnal pain, pain while walking and fatigue were assessed by self-reported questionnaires at baseline and 2-year follow-up. Associations between these biomarkers and symptoms were examined using logistic and linear regression analyses.

RESULTS

hs-CRP was significantly associated with mild nocturnal pain (OR 1.18 95% CI 1.01-1.37), with mild and moderate pain while walking (OR 1.17 95% CI 1.01-1.35 and OR 1.56 95% CI 1.29-1.90, respectively) and with progression of nocturnal pain (OR 1.25 95% CI 1.07-1.46). uCTX-2 was associated with mild nocturnal pain (OR 1.40 95% CI 1.05-1.85) and with mild and severe-extreme pain while walking (OR 1.35 95% CI 1.04-1.75 and OR 2.55 95% CI 1.03-6.34, respectively). sPINP was associated with severe-extreme nocturnal pain (OR 0.45 95% CI 0.25-0.82). No significant associations were found for sCOMP and sOC, nor for any of the biomarkers and fatigue.

CONCLUSION

This study of biomarkers in a large cohort of participants with hip and/or knee pain suspected to reflect early stage hip and/or knee OA suggests that inflammation and cartilage matrix degeneration play a role in pain, but not in fatigue.

The Relationship between Serum Sclerostin Levels and Bone Mineral Disorders and Vascular Calcification in Hemodialysis Patients

Background and aim of the study: Sclerostin is produced by osteocytes and has been shown to down-regulate the synthesis of many markers of bone formation by osteogenic cells. The aim of this study to investigate the relationship between serum sclerostin levels and bone mineral disorders and vascular calcification in hemodialysis patients (HD). Methods:This is a cross-sectional study of 70 patients with ESRD on regular HD for at least six months, Theodor Bilharz Research Institute, Giza, Egypt.Twenty-five subjects who matched the ages, genders, and demographics of the study patients were included as a control group.All patients and control groups included in the study underwent a full through history and clinical examination. Serum calcium, phosphorus, alkaline phosphatase and intact PTH (iPTH) levels were measured. Serum sclerostin was measured by an ELISA. Bone Mineral Densitometry Measurements BMD (g/cm2) was determined by dual-energy X-ray absorptiometry (DXA). CT scan was done to detect the presence or absence of vascular calcification and transthoracic echocardiogram to detect the presence or absence of  valvular calcification. Results:The mean seumscleostin levels was a statistically significant high in the HD patients when compared with the control group (156.8 ±121.4 Vs.29.38±0.84,  p =0.0001 ) and statistically significant high mean ALP in the HD patients when compared with the control group (147.2 ± 94.3      Vs.              38.8 ±23.4, p = 0.0001). The mean BMD  was statistically significant low in the HD patients when compared with the controls (0.839±0.086 g/ m2 Vs.1.306  ±0.153 g/ m2, p = 0.0001).The mean seumscleostin levels was statistically significant high in the HD patients with vascular and valvular  calcification  when compared with HD patients without calcification.Using spearman correlation coefficient analysis, there was  statistically significant negative correlations between serum sclerostin levels and iPTH(r=-0.362,   p =0.0021), ALP (r=-0.301, p =0.0114), and BMD (r=-0.469, p =0.0278 ), and there was a statistically significant positive correlation between serum sclerostin levels and phosphate(r=0.5829,  p =0.0001 ).Independent predictors of BMD in HD patients were determined using multi-variate regression analysis. Sclerostin levels, iPTH, ALP, and age  were found to be independent predictors of BMD. Conclusion: High sclerostin levels in patients with ESRD on HD were associated with high risk of vascular and valvularcalcification and were independent predictors of low BMD in such population.

Age-related trends and reference intervals of cross-linked C-telopeptide of type I collagen and procollagen type I N-propeptide from a reference population of Sri Lankan adult women

Refer ence values of bone turnover markers (BTMs) are determined by factors that are country-specific. In Sri Lanka, unavailability of BTM reference data has led to their non-use in management of osteoporosis. The results of this study can be used as reference data for women in Sri Lanka.

INTRODUCTION

This study was performed to establish age-related reference intervals for bone resorption marker; cross-linked C-telopeptide of type I collagen (CTX) and bone formation marker; procollagen type I N-propeptide (PINP) in a group of Sri Lankan adult women.

METHODS

Adult women (n = 347) aged 20-70 years were recruited using age-stratified random sampling technique and categorized into age groups by decades. Serum CTX and PINP concentration were measured using enzyme-linked immunosorbent assay (ELISA). The geometric mean (95% confidence interval) and 2.5th and 97.5th percentiles were calculated. ANOVA was used to compare the means between groups.

RESULTS

Mean CTX levels were relatively low and remained unchanged between 20 and 49 years. After the age of 49 years, mean CTXconcentration elevated significantly until the age of 70 years (43%, p < 0.001). Mean PINP concentrations were not significantly different between age categories (p > 0.05). Reference intervals of CTX and PINP were based on 2.5th and 97.5th percentile values. Reference intervals of CTX for the age groups of 20-29, 30-39, 40-49, 50-59, and 60-70 years were 0.19-0.97 ng/mL, 0.18-0.95 ng/mL, 0.20-1.29 ng/mL, 0.17-2.20 ng/mL, and 0.17-2.85 ng/mL respectively. Reference intervals of PINP for the same age groups were 118-810 pg/mL, 119-772 pg/mL, 116-645 pg/mL, 108-684 pg/mL, and 108-715 pg/mL respectively.

CONCLUSION

In Sri Lanka, bone turnover markers are not used in evaluating patients mainly due to lack of normative data. These values can be used as reference data for women in this age group.

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

The aim of this study was to provide definitive reference values for bone mineral density (BMD) and bone turnover markers in the general elderly population. Registered citizens of 50 to 89 years old were targeted for this survey. After random sampling from the resident registry of Obuse town, we established eight groups based on age (50 s, 60 s, 70 s, and 80 s) and gender. A total of 411 people were enrolled. We used a dual-energy x-ray absorptiometry device to measure and evaluate BMD. The bone formation marker bone alkaline phosphatase (BAP) was measured as a bone turnover marker. Bone quality marker pentosidine, and bone resorption markers including urinary total deoxypyridinoline (DPD), tartrate-resistant acid phosphatase 5b (TRACP-5b), 25-hydroxyvitamin D (25[OH]D), and whole parathyroid hormone (PTH) were also measured as bone turnover markers. Sixty-three people (15.3%) were diagnosed as osteoporosis. BMD decreased with age in the femoral neck and total hip. On the other hand, there was no characteristic change with age in the lumber spine. As for bone markers, pentosidine and DPD increased with aging, although 25(OH)D, whole PTH, and BAP showed no characteristic associations with gender and aging. In terms of the relationship between low BMD and bone markers, there was a significant independent association between low BMD and TRACP-5b in females. In conclusions, hip BMD decreased with aging in men and women. However, there was no characteristic decline with aging in the lumbar spine. All bone markers showed no significant independent characteristics associated with age or gender in a multivariate analysis model, except for a significant association between low BMD and TRACP-5b in females. TRACP-5b was a potentially useful marker for the detection of low BMD.

Association of RANKL and OPG Gene Polymorphism in Arab Women with and without Osteoporosis

Receptor activator of the nuclear factor-κB ligand (RANKL) and osteoprotegerin genes (OPG) were identified as susceptible loci for postmenopausal osteoporosis (PMO) in various ethnicities, but neither have been studied in an Arabian population. Hence, the current study aimed to fill this gap. A total of 372 postmenopausal women (174 osteoporosis (OP) and 198 control group (CTRs)) were genotyped for four SNPs: rs2277438A/G and rs9533156T/C (RANKL), and rs2073618C/G and rs3102735T/C (OPG). Anthropometrics, bone mineral density, 25(OH)D and several other bone markers were measured. The frequency distribution of the heterozygous CG genotype of rs2073618 (OPG) was lower in the OP (36.8%) than in CTRs (47%) (OR: 0.6, 95% CI: 0.3–0.97; p = 0.041). No differences in the allelic/genotypic frequencies were detected between the two groups for all other studied SNPs. However, the heterozygous TC genotype of rs3102735 (OPG) was associated significantly with lower BMD at the femoral neck in OP subjects (p = 0.04). The homozygous rare CC genotype of rs9533156 (RANKL) was associated with lower 25(OH)D levels in CTRs (p = 0.032). In contrast, heterozygous AG genotype of rs2277438 (RANKL) is associated with lower 25(OH)D in the OP group (p = 0.02). Our results suggest that RANKL SNPs may impact 25(OH)D levels and that OPG SNP rs2073618A/G is a significant genetic risk factor for PMO Saudi Arabian women.

Age- and sex-specific concentrations of bone remodeling markers in healthy Indian adults with and without vitamin D deficiency

Bone remodeling markers exhibit marked inter-ethnic variation; hence, population-specific data are required. Herein, we have established age- and sex-specific concentrations of serum PINP and CTX in healthy Indian adults with and without vitamin D deficiency that can be used in clinical practice for monitoring response to anti-osteoporotic therapy.

OBJECTIVE

The present study was undertaken to generate data on age- and sex-specific concentrations of serum procollagen type I N-propeptide (PINP) and type I collagen C-telopeptide (CTX) in healthy Indian adults with and without vitamin D deficiency.

METHODS

Apparently, healthy subjects aged ≥ 20 years with no prior co-morbidities were recruited from the community by door-to-door surveys. Provisionally eligible participants underwent blood sampling after overnight fast. Individuals with biochemical abnormalities that could potentially affect bone remodeling were excluded. However, subjects with vitamin D deficiency were not excluded. Serum total PINP and β-CrossLaps (CTX) were measured using electro-chemiluminescence immunoassay.

RESULTS

After exclusion, 677 subjects were enrolled (M:F = 2.5:4.2, mean age = 45.0 years). Median serum PINP and CTX were 55.78 ng/ml (40.27-71.70) and 0.356 ng/ml (0.238-0.499), respectively. There was no difference in PINP/CTX between men and women or between premenopausal and postmenopausal women. Decade-wise distribution of PINP/CTX showed that maximum values were attained in 3rd decade; subsequently, in men, levels declined with age while in women, there was a peak in the 6th decade coinciding with the early years of menopause. Vitamin D deficiency and severe vitamin D deficiency were seen in 417 (61.5%) and 259 subjects (38.2%), respectively. There was no significant difference in PINP/CTX in subjects with and without vitamin D deficiency.

CONCLUSIONS

The present study has allowed us to generate data on serum concentrations of PINP/CTX in a diverse group of healthy community-dwelling Indian adults with varying serum vitamin D levels. It might aid in monitoring response to anti-osteoporotic therapy amongst native Indians.

Fusion Potential of Human Osteoclasts In Vitro Reflects Age, Menopause, and In Vivo Bone Resorption Levels of Their Donors-A Possible Involvement of DC-STAMP

It is well established that multinucleation is central for osteoclastic bone resorption. However, our knowledge on the mechanisms regulating how many nuclei an osteoclast will have is limited. The objective of this study was to investigate donor-related variations in the fusion potential of in vitro-generated osteoclasts. Therefore, CD14⁺ monocytes were isolated from 49 healthy female donors. Donor demographics were compared to the in vivo bone biomarker levels and their monocytes’ ability to differentiate into osteoclasts, showing that: (1) C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) levels increase with age, (2) the number of nuclei per osteoclast in vitro increases with age, and (3) there is a positive correlation between the number of nuclei per osteoclast in vitro and CTX levels in vivo. Furthermore, the expression levels of the gene encoding dendritic cell-specific transmembrane protein (DCSTAMP) of osteoclasts in vitro correlated positively with the number of nuclei per osteoclast, CTX levels in vivo, and donor age. Our results furthermore suggest that these changes in gene expression may be mediated through age-related changes in DNA methylation levels. We conclude that both intrinsic factors and age-induced increase in fusion potential of osteoclasts could be contributing factors for the enhanced bone resorption in vivo, possibly caused by increased expression levels of DCSTAMP.

Reference Intervals for Bone Turnover Markers in Korean Healthy Women

Background

Adequate suppression of bone turnover rate is important to decrease fracture risk without mineralization defect due to oversuppression. This study was performed to determine reference intervals (RIs) for 2 bone turnover markers, serum C-terminal telopeptide of type I collagen (CTX) and osteocalcin, in Korean women.

Methods

A total of 461 Korean women (287 premenopausal and 174 postmenopausal) without any disease or drug history affecting bone metabolism was included. Serum CTX and osteocalcin were measured after overnight fasting. Bone mineral density (BMD) was measured at the 1st to 4th lumbar vertebra using dual energy X-ray absorptiometry. Subjects with normal spinal BMD (T-score ≥-1.0) were included in this study.

Results

After stable concentrations were maintained, both CTX and osteocalcin were abruptly increased in 50 to 59 years, and then decreased with increasing age. Median levels and interquartile range of serum CTX and osteocalcin in all subjects were 0.322 (0.212-0.461) ng/mL and 15.68 (11.38-19.91) ng/mL. RIs for serum CTX and osteocalcin in all subjects were 0.115 to 0.861 ng/mL and 6.46 to 36.76 ng/mL. Those were higher in postmenopausal women (CTX, 0.124-1.020 ng/mL, osteocalcin, 5.42-41.57 ng/mL) than in premenopausal women (CTX, 0.101-0.632 ng/mL, osteocalcin, 6.73-24.27 ng/mL). If we use target reference levels as lower half of premenopausal 30 to 45 years in patients with antiresorptive drugs, those were 0.101 to 0.251 ng/mL and 6.40 to 13.36 ng/mL.

Conclusions

We established RIs for serum CTX and osteocalcin in healthy Korean women with normal lumbar spine BMD. Premenopausal RIs for serum CTX and osteocalcin would be useful to monitor patients with low bone mass using osteoporosis drugs.

Effects of age and sex on osteocalcin and bone-specific alkaline phosphatase-reference intervals and confounders for two bone formation markers

Bone formation markers bone-specific alkaline phosphatase and osteocalcin are used in many clinical situations. Therefore, we calculated reference intervals for the two markers and investigated how they are influenced by several factors including sex and age. Furthermore, we established clinically relevant reference intervals for the two markers.

OBJECTIVE

The bone turnover markers (BTMs), bone-specific alkaline phosphatase (bone ALP), and osteocalcin (OC), are frequently measured formation markers. The purpose of this study was to establish reference intervals (RIs) for the two BTMs in a general adult Danish population.

METHODS

Bone ALP and OC were measured on the iSYS (IDS Plc) automatic analyzer in samples from the Danish Health2006 5-year follow-up study on serum from 2308 participants (54% women, age range 24-76). Participants with self-reported diagnosis of osteoporosis or receiving hormonal replacement were excluded from analyses while participants on hormonal contraceptives were included.

RESULTS

The geometric mean and 95%RI for bone ALP were 13.9 μg/L (7.6-25.6) for men and 13.8 μg/L (7.0-27.4) for women, while for OC 16.0 μg/L (7.5-34.4) for men and 18.6 μg/L (8.1-42.9) for women. Levels of bone ALP increased with increasing age (β 1.004, p < 0.001), while female sex had no effect. OC levels decreased with increasing age (β 0.998, p = 0.009) and increased with female sex (β 1.104, p < 0.001). Based on our findings, we propose for bone ALP and OC three clinical RIs for men based on age and three clinical RI for women based on age and menopausal status.

CONCLUSION

The RI for bone ALP and OC varies with age and sex and the BTMs are influenced differently by the two factors. Consequently, the need for establishing valid RIs is of great importance before the full potential of BTM can be used in clinical practice.

Viewpoint on the role of tissue maintenance in ageing: focus on biomarkers of bone, cartilage, muscle, and brain tissue maintenance

Specific hallmarks are thought to underlie the ageing process and age-related functional decline. In this viewpoint, we put forward the hypothesis that disturbances in the process of tissue maintenance are an important common denominator that may lie in between specific hallmarks of ageing (i.e. damage and responses to damage) and their ultimate (patho)physiological consequences (i.e. functional decline and age-related disease). As a first step towards verifying or falsifying this hypothesis, it will be important to measure biomarkers of tissue maintenance in future studies in different study populations. The main aim of the current paper is to discuss potential biomarkers of tissue maintenance that could be used in such future studies. Among the many tissues that could have been chosen to explore our hypothesis, to keep the paper manageable, we chose to focus on a selected number of tissues, namely bone, cartilage, muscle, and the brain, which are important for mobility and cognition and affected in several common age-related diseases, including osteoporosis, osteoarthritis, sarcopenia, and neurodegenerative diseases. Furthermore, we discuss the advantages and limitations of potential biomarkers for use in (pre)clinical studies. The proposed biomarkers should be validated in future research, for example by measuring these in humans with different rates of ageing.

Reduced Serum Osteocalcin in High-Risk Alcohol Using People Living With HIV Does Not Correlate With Systemic Oxidative Stress or Inflammation: Data From the New Orleans Alcohol Use in HIV Study

BACKGROUND

HIV infection is now largely a chronic condition as a result of the success of antiretroviral therapy. However, several comorbidities have emerged in people living with HIV (PLWH), including alcohol use disorders and musculoskeletal disorders. Alcohol use has been associated with lower bone mineral density, alterations to circulating bone turnover markers, and hypocalcemia. The pathophysiological basis of bone loss in the PLWH population is unclear but has been suggested to be linked to oxidative stress and inflammation. To test the hypothesis that PLWH consuming excessive alcohol have altered markers of bone turnover and/or calcium homeostasis in association with oxidative stress, we correlated measurements of alcohol consumption with markers of oxidative stress and inflammation, serum calcium concentrations, and measurements of bone turnover, including c-terminal telopeptide cross-links (CTX-1) and osteocalcin.

METHODS

Data were drawn from cross-sectional baseline data from the ongoing New Orleans Alcohol Use in HIV (NOAH) study, comprised of 365 in care PLWH. Alcohol consumption measures (Alcohol Use Disorders Test, 30-day timeline follow-back calendar, and phosphatidylethanol [PEth]) were measured in a subcohort of 40 subjects selected based on highest and lowest PEth measurements. Multivariate linear regression was performed to test the relationships between alcohol consumption and systemic oxidative stress (4-hydroxynonenal; 4-HNE) and inflammation (c-reactive protein; CRP).

RESULTS

Serum calcium and CTX-1 did not differ significantly between the high and low-PEth groups. Individuals in the high-PEth group had significantly lower serum osteocalcin (median low-PEth group: 13.42 ng/ml, inter-quartile range [IQR] 9.26 to 14.99 ng/ml; median high-PEth group 7.39 ng/ml, IQR 5.02 to 11.25 ng/ml; p = 0.0005, Wilcoxon rank-sum test). Osteocalcin negatively correlated with PEth (Spearman r = -0.45, p = 0.05) and self-reported measures after adjusting for covariates. Alcohol consumption showed mild, but significant, positive associations with serum 4-HNE, but not with CRP. Osteocalcin did not correlate with either 4-HNE or CRP.

CONCLUSIONS

In this subcohort of PLWH, we detected significant associations between at-risk alcohol use and osteocalcin, and at-risk alcohol use and serum 4-HNE, suggesting suppression of bone formation independent of increased systemic oxidative stress with increasing alcohol consumption.

The 24-hour serum profiles of bone markers in healthy older men and women

The process of bone turnover displays variations over 24 h, with C-terminal cross-linked telopeptide of type 1 collagen (CTX) and osteocalcin exhibiting a nadir in the afternoon and a peak in the night. In contrast, N-terminal propeptide of type 1 procollagen (P1NP) did not display an apparent 24-hour rhythm. Other emerging novel biomarkers of bone, sclerostin and Dickkopf-related protein 1 (DKK1), are markers of osteocyte activity with limited data available regarding their 24-hour profiles. In this study, we aimed to extend available data on 24-hour profiles of CTX, osteocalcin, and P1NP and to assess the 24-hour profiles of sclerostin and DKK1 in healthy older men and women and to compare these between men and women. We measured these five bone markers in EDTA plasma collected every 4 h during 24 h in 37 healthy older men and women (range 52-76 years). Differences between time points were determined using repeated measures ANOVA and cosinor analyses were performed to determine circadian rhythmicity. The circadian rhythm of CTX was confirmed by the cosinor model, with women showing larger amplitude compared to men. Osteocalcin showed higher levels during nighttime compared to daytime in both men and women. For P1NP levels we observed a small but significant increase in the night in men. Sclerostin and DKK1 did not show a circadian rhythm, but sclerostin levels differed between time points. Because of the large intraindividual variation, DKK1 as measured in this study cannot be considered a reliable marker for diagnostic or research purposes. In conclusion, when measuring CTX, osteocalcin, P1NP, or sclerostin either in clinical practice or in a research setting, one should consider the 24-hour profiles of these bone markers.

Age-related Reference Intervals for Total Collagen-I-N-terminal Propeptide in Healthy Korean Population

Background

Procollagen type I N-terminal propeptide (PINP) is one of the most clinically useful bone formation biomarkers. Therefore, the purpose of this study was to independently evaluate the performance of automated total PINP assay and established age- and gender-specific reference intervals for PINP in healthy Korean population.

Methods

The imprecision, linearity, and detection capability of Elecsys total PINP assay was determined and reference interval was established using 599 serums from Korean population with normal bone mineral densities based on bone densitometry. Age groups were divided into 20s, 30s, 40s, 50s, 60s and over.

Results

Elecsys total PINP had excellent performance in imprecision, linearity, and detection capability. When partitioning age groups in Korean male and female populations, there was significant difference in total PINP between different age groups. In male populations, PINP level was decreased with increasing age, then it remained steady after middle-age. In female populations, there was a decreasing tendency similar to that in the male population with a sharp increase in the 50 to 59 age group.

Conclusions

Elecsys total PINP assay showed precise and reliable performance in our study. We established age-related PINP reference intervals for Korean male and female population with normal bone mineral densities.

Dental Panoramic Radiographic Indices as a Predictor of Osteoporosis in Postmenopausal Saudi Women

Background

Many oral presentations of osteoporosis-a bone metabolic disease-were recorded. Thus, we aimed to assess panoramic radiomorphometric indices with bone mineral density (BMD) values among Saudi postmenopausal women and its importance in the prediction of osteoporosis.

Methods

A total of 431 Saudi women were enrolled in this study. Panoramic radiographs were obtained at the time of BMD measurement. Subjects were fatherly classified into; normal BMD, osteopenia, and osteoporosis groups. Serum follicle-stimulating hormone, luteinizing hormone (LH), estradiol (E2), 25-hydroxy-vitamin D (25[OH]D) and intact-parathyroid hormone were measured. Moreover, serum creatinine, calcium, and phosphate, together with serum osteocalcin (s-OC), procollagen type I N-terminal propeptide (s-PINP) and cross-linked C-terminal telopeptide of type 1 collagen (s-CTX) were measured. Receiver-operator curve (ROC) curve analysis for use of mandibular cortical width (MCW), panoramic mandibular index (PMI), and maxillary-mandibular ratio (M/M ratio) to differentiate women with osteoporosis or osteopenia from normal subjects was calculated. Cut off values of 4.6 at T score <−1 and 4.1 at T score ≤−2.5 were used.

Results

Body mass index is significantly low in the osteoporotic group. There is no significant difference in serum levels of LH, E2, calcium, phosphate, and 25(OH)D between the studied groups. Moreover, s-OC, C-terminal propeptide of procollagen type I, s-PINP, s-CTX, and urinary-CTX are significantly higher in osteoporosis than normal and osteopenia groups. ROC curve analysis revealed that MCW and PMI showed significant data while M/M ratio is non-significant.

Conclusions

It could be concluded that MCW as an important panoramic radiographic parameter can be used for prediction and diagnosis of osteoporosis in postmenopausal Saudi women with low BMD.

Bone turnover markers after the menopause: T-score approach

Bone turnover increases at the menopause and is associated with accelerated bone loss. However, it is not known to what extent there is an imbalance between the processes of bone resorption and bone formation, nor whether it is the rate of bone turnover or the bone balance that is most closely associated with the rate of bone loss. We studied 657 healthy women ages 20 to 79 from five European cities (the OPUS Study) and divided them into two premenopausal age groups, 20 to 29 (n=129), 30 to 39years (n=183), and three postmenopausal groups 1 to 10years (n=91), 11 to 20years (n=131) and 21+ years since menopause (n=123). We measured collagen type I C-telopeptide (CTX, a marker of bone resorption) and procollagen I N-propeptide (PINP, a marker of bone formation). We used these two markers to calculate the overall bone turnover and the difference between bone formation and resorption (bone balance) using the results from the women ages 30 to 39years to calculate a standardised score (T-score). We found that the CTX and PINP levels were higher in the women ages 20 to 29 and in the women in the three menopausal groups as compared to women ages 30 to 39years (p<0.001). For example, the CTX and PINP levels were 80 and 33% higher in women 1 to 10years since menopause as compared to women ages 30 to 39years. In this group of postmenopausal women, the bone turnover expressed as a T-score was 0.72 (0.57 to 0.88, 95%CI) and the bone balance was -0.37 (-0.59 to -0.16). There was greater rate of bone loss from the total hip in all the groups of women after the menopause compared to women before the menopause. We conclude that the bone loss after the menopause is associated with both an increase in bone turnover and a negative bone balance and that bone loss was most clearly associated with overall bone turnover.

High Plasma Sphingosine 1-phosphate Levels Predict Osteoporotic Fractures in Postmenopausal Women: The Center of Excellence for Osteoporosis Research Study

Background

Higher sphingosine 1-phosphate (S1P) plasma levels are associated with decreased bone mineral density (BMD), and increased risk of prevalent vertebral fracture. So, we hypothesized that postmenopausal women with increased baseline plasma S1P levels have a greater risk for future incident fracture (osteoporosis-related fractures [ORFs]).

Methods

This study was conducted in a prospective longitudinal cohort of 707 women recruited in 2004 and followed up annually for a mean period of 5.2±1.3 years. They were postmenopausal (aged ≥50 years). The primary outcome measure was the time to the first confirmed ORF event using radiographs and/or a surgical report.

Results

The plasma S1P levels (µmol/L) were significantly higher in the women with incident fracture (7.23±0.79) than in those without ORFs (5.02±0.51; P<0.001). High S1P levels were strongly associated with increased fracture risk. After adjustment for age and other confounders, the hazard ratio (HR) was 6.12 (95% confidence interval [CI], 4.92−7.66) for each 1-standard deviation increase in plasma S1P levels. The women in the highest quartile of S1P levels had a significant increase in fracture risk (HR, 9.89; 95% CI, 2.83−34.44). Results were similar when we compared plasma S1P levels at the 1-year visit.

Conclusions

The associations between plasma S1P levels and fracture risk were independent of BMD and other confounders. These findings demonstrate that high plasma S1P level at baseline and at years 1 to 5 is a strong and independent risk factor for future [ORFs] among postmenopausal women and could be a useful biomarker for fracture risk assessment in this population.

Bone Turnover Status: Classification Model and Clinical Implications

Aim: To develop a practical model for classification bone turnover status and evaluate its clinical usefulness. Methods: Our classification of bone turnover status is based on internationally recommended biomarkers of both bone formation (N-terminal propeptide of type1 procollagen, P1NP) and bone resorption (beta C-terminal cross-linked telopeptide of type I collagen, bCTX), using the cutoffs proposed as therapeutic targets. The relationships between turnover subtypes and clinical characteristic were assessed in1223 hospitalised orthogeriatric patients (846 women, 377 men; mean age 78.1±9.50 years): 451(36.9%) subjects with hip fracture (HF), 396(32.4%) with other non-vertebral (non-HF) fractures (HF) and 376 (30.7%) patients without fractures. Resalts: Six subtypes of bone turnover status were identified: 1 - normal turnover (P1NP>32 μg/L, bCTX≤0.250 μg/L and P1NP/bCTX>100.0[(median value]); 2- low bone formation (P1NP ≤32 μg/L), normal bone resorption (bCTX≤0.250 μg/L) and P1NP/bCTX>100.0 (subtype2A) or P1NP/bCTX<100.0 (subtype 2B); 3- low bone formation, high bone resorption (bCTX>0.250 μg/L) and P1NP/bCTX<100.0; 4- high bone turnover (both markers elevated ) and P1NP/bCTX>100.0 (subtype 4A) or P1NP/bCTX<100.0 (subtype 4B). Compared to subtypes 1 and 2A, subtype 2B was strongly associated with nonvertebral fractures (odds ratio [OR] 2.0), especially HF (OR 3.2), age>75 years and hyperparathyroidism. Hypoalbuminaemia and not using osteoporotic therapy were two independent indicators common for subtypes 3, 4A and 4B; these three subtypes were associated with in-hospital mortality. Subtype 3 was associated with fractures (OR 1.7, for HF OR 2.4), age>75 years, chronic heart failure (CHF), anaemia, and history of malignancy, and predicted post-operative myocardial injury, high inflammatory response and length of hospital stay (LOS) above10 days. Subtype 4A was associated with chronic kidney disease (CKD), anaemia, history of malignancy and walking aids use and predicted LOS>20 days, but was not discriminative for fractures. Subtype 4B was associated with fractures (OR 2.1, for HF OR 2.5), age>75 years, CKD and indicated risks of myocardial injury, high inflammatory response and LOS>10 days. Conclusions: We proposed a classification model of bone turnover status and demonstrated that in orthogeriatric patients altered subtypes are closely related to presence of nonvertebral fractures, comorbidities and poorer in-hospital outcomes. However, further research is needed to establish optimal cut points of various biomarkers and improve the classification model.

Bone turnover marker determinants in young women: results from the Safe-D study

Background Bone turnover markers (BTMs) may provide insight into bone health in young women, but have been little studied in this demographic. We aimed to explore the association between body composition, hormonal contraception, bone mineral density and biochemical parameters and BTMs in young women. Methods Participants were community-dwelling females aged 16-25 years, living in Victoria, Australia. Carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX) and total procollagen type 1 N-propeptide (P1NP) were analysed on the Roche Elecsys automated analyzer. A total of 305 were evaluated, after excluding participants with medical conditions or medications (except hormonal contraceptives), which may affect bone metabolism. Results Median (Q1, Q3) BTM values were 540 (410, 690) ng/L for CTX and 61.7 (46.2, 83.7) µg/L for P1NP. Serum CTX and P1NP were inversely associated with chronological age ( P < 0.001), transferrin ( P < 0.020) and serum dehydroepiandrosterone sulphate concentration ( P < 0.001). BTM values were up to 22% lower in combined oral contraceptive (COC) pill users ( P < 0.001). Serum CTX was inversely associated with per cent body fat ( P = 0.009) and tibial cortical volumetric bone mineral density (vBMD; P = 0.003). Serum P1NP concentrations were 23  µg/L higher in participants who reported using an osteopath in the previous year ( P = 0.007). Conclusions These data suggest that BTMs are influenced by age, COC use, body composition, iron status and hormonal profiles. Higher CTX values were associated with lower tibial cortical vBMD. Examining BTMs in relation to interventions aimed at improving bone health in young women is warranted.

Low bone turnover in premenopausal women with type 2 diabetes mellitus as an early process of diabetes-associated bone alterations: a cross-sectional study

BACKGROUND

Individuals with Diabetes Mellitus (DM) are at increased risk for fracture due to the decrease in bone strength and quality. Serum procollagen type I intact N-terminal (P1NP) and serum C-terminal cross-linking telopeptide of type I collagen (CTX) as markers of bone formation and resorption, respectively, have been reported to be decreased in T2DM. It remains unclear whether diabetes-associated alterations in the bone turnover of T2DM individuals are related to the longer duration of the disease or may occur earlier. Furthermore, previous studies on BTMs in T2DM individuals have mostly been done in postmenopausal women with T2DM, which might have masked the DM-induced alterations of bone turnover with concurrent estrogen deficiency. This study aims to assess the levels of serum P1NP and CTX as markers of bone turnover in premenopausal women with and without T2DM.

METHODS

This cross-sectional study involves 41 premenopausal women with T2DM, and 40 premenopausal women without DM. Sampling was done consecutively. P1NP and CTX measurement was done using the electrochemi-luminescence immunoassay (ECLIA) method. Other data collected include levels of HbA1C, ALT, creatinine, eGFR and lipid profile.

RESULTS

Median (interquartile range) P1NP in T2DM is 29.9 ng/ml (24.7-41.8 ng/ml), while in non-DM is 37.3 ng/ml, (30.8-47.3 ng/ml; p = 0.007). Median (interquartile range) CTX in T2DM is 0.161 ng/ml (0.106-0.227 ng/ml), while in non-DM is 0.202 ng/ml (0.166-0.271 ng/ml; p = 0.0035). Levels of P1NP and CTX in the T2DM group did not correlate with the duration of disease, age, BMI or the levels of HbA1C.

CONCLUSIONS

Premenopausal women with T2DM indeed have lower bone turnover when compared with non-DM controls. This significantly lower bone turnover process starts relatively early in the premenopausal age, independent of the duration of DM. Gaining understanding of the early pathophysiology of altered bone turnover may be key in developing preventive strategies for diabetoporosis.

Comparison of two automated assays of BTM (CTX and P1NP) and reference intervals in a Danish population

Bone turnover markers are used for monitoring osteoporosis treatment. Therefore, we evaluated the agreement between different assays for CTX and PINP and established reference intervals in a cohort of 2300 individuals. We found poor agreement between assays and different reference intervals. This highlights the importance of harmonization of the assays.

INTRODUCTION

Two reference markers for bone turnover have been proposed: CTX bone resorption and P1NP for bone formation. The purpose of the current study was to establish reference intervals for the two markers in a Danish cohort and to determine the agreement on the two platforms.

METHODS

Fasting sera from 2308 individuals (1250 males and 1058 females, age range 24-76 years) participating in the Health2006 study were analyzed for CTX and P1NP using the automated IDS-iSYS analyzer and the automated Cobas e411 analyzer. Participants in anti-osteoporotic treatment were excluded, while subjects on hormonal contraceptives were included.

RESULTS

There was significant disagreement between both the two P1NP assays with a mean difference of -3 μg/L (LoA -19 to 14) (p < 0.001) and the two CTX assays with a mean difference of 13 ng/L (LoA-187 to 214) (p < 0.001). For CTX, there was a systematic bias: at low values, Cobas measured a higher value than iSYS and at higher concentrations, iSYS measured increasingly higher values than Cobas. Based on the results, we propose three reference intervals for each sex: 25-29, 30-39, and 40-80 years for men, and 25-29, >30 (pre-menopausal), and >30 years (post-menopausal) for women.

CONCLUSIONS

There is significant disagreement between the IDS-iSYS and Roche Cobas assays for both reference markers. Consequently, the reference intervals for an adult, healthy population are different depending on the analysis method used. Therefore, repeated measurements of patient samples used for monitoring of treatment should be done on the same assay. Moreover, assay-specific reference intervals should be used. Harmonization of assays for BTM is highly warranted.

Elevated Bone Turnover Markers after Risk-Reducing Salpingo-Oophorectomy in Women at Increased Risk for Breast and Ovarian Cancer

BACKGROUND

Risk-reducing salpingo-oophorectomy (RRSO) reduces ovarian cancer risk in BRCA1/2 mutation carriers. Premenopausal RRSO is hypothesized to increase fracture risk more than natural menopause. Elevated bone turnover markers (BTMs) might predict fracture risk. We investigated BTM levels after RRSO and aimed to identify clinical characteristics associated with elevated BTMs.

METHODS

Osteocalcin (OC), procollagen type I N-terminal peptide (PINP) and serum C-telopeptide of type I collagen (sCTx) were measured in 210 women ≥ 2 years after RRSO before age 53. BTM Z-scores were calculated using an existing reference cohort of age-matched women. Clinical characteristics were assessed by questionnaire.

RESULTS

BTMs after RRSO were higher than age-matched reference values: median Z-scores OC 0.11, p = 0.003; PINP 0.84, p < 0.001; sCTx 0.53, p < 0.001 (compared to Z = 0). After excluding women with recent fractures or BTM interfering medication, Z-scores increased to 0.34, 1.14 and 0.88, respectively. Z-scores for OC and PINP were inversely correlated to age at RRSO. No correlation was found with fracture incidence or history of breast cancer.

CONCLUSIONS

Five years after RRSO, BTMs were higher than age-matched reference values. Since elevated BTMs might predict higher fracture risk, prospective studies are required to evaluate the clinical implications of this finding.

Measurement and Clinical Utility of βCTX in Serum and Plasma

Biochemical markers of bone turnover (BTM) are released during bone remodeling and can be measured in blood or urine as noninvasive surrogate markers for the bone remodeling rate. The C-terminal cross-linked telopeptide of type I collagen (βCTX) is released during bone resorption and is specific to bone tissue. Assays have been developed to measure βCTX in blood and in urine; most current use of βCTX measurement for research and in clinical practice is performed on a blood sample. Method-specific differences for serum and plasma βCTX have led to initiatives to standardize or harmonize βCTX commercial assays. βCTX demonstrates significant biological variation due to circadian rhythm and effect of food which can be minimized by standardized sample collection in the fasting state in the morning. While βCTX predicts fracture risk independent of bone mineral density, lack of data has precluded its inclusion in fracture risk calculators. The changes seen in βCTX with antiresorptive therapies have been well characterized and this has led to its widespread use for monitoring therapy in osteoporosis. However, more fracture-based data on appropriate treatment goals for monitoring need to be developed. Evidence is lacking for the use of βCTX in managing "drug holidays" of bisphosphonate treatment in osteoporosis or risk stratifying those at increased risk of developing osteonecrosis of the jaw. βCTX is useful as an adjunct to imaging techniques for the diagnosis of Paget's disease of bone and for monitoring therapy and detecting recurrence. βCTX also shows promise in the management of metastatic bone disease.

Bone turnover markers: Emerging tool in the management of osteoporosis

Bone is a dynamic tissue which undergoes constant remodeling throughout the life span. Bone turnover is balanced with coupling of bone formation and resorption at various rates leading to continuous remodeling of bone. A study of bone turnover markers (BTMs) provides an insight of the dynamics of bone turnover in many metabolic bone disorders. An increase in bone turnover seen with aging and pathological states such as osteoporosis leads to deterioration of bone microarchitecture and thus contributes to an increase in the risk of fracture independent of low bone mineral density (BMD). These microarchitectural alterations affecting the bone quality can be assessed by BTMs and thus may serve as a complementary tool to BMD in the assessment of fracture risk. A systematic search of literature regarding BTMs was carried out using the PubMed database for the purpose of this review. Various reliable, rapid, and cost-effective automated assays of BTMs with good sensitivity are available for the management of osteoporosis. However, BTMs are subjected to various preanalytical and analytical variations necessitating strict sample collection and assays methods along with utilizing ethnicity-based reference standards for different populations. Estimation of fracture risk and monitoring the adherence and response to therapy, which is a challenge in a chronic, asymptomatic disease such as osteoporosis, are the most important applications of measuring BTMs. This review describes the physiology of bone remodeling, various conventional and novel BTMs, and BTM assays and their role in the assessment of fracture risk and monitoring response to treatment with antiresorptive or anabolic agents.

Bone turnover markers and bone mineral density in healthy mother-daughter pairs from South India

Bone turnover markers (BTMs) provide important insights into the dynamics of bone remodelling and are subjected to preanalytical and ethnic variations in addition to influence of genetic and environmental factors.

AIM/OBJECTIVES

To derive ethnicity specific reference range for BTMs and to study their correlation with Bone Mineral Density (BMD) in a cohort of healthy postmenopausal women and their premenopausal daughters and to look at the impact of maternal bone mineral status on daughters bone health.

MATERIAL AND METHODS

This community based cross sectional study included 300 subjects (150 mother-daughter pairs). Demographic details were collected. Fasting blood and a second void morning urine samples were obtained for measurement of BTMs (sCTX, sPTNP1, sOC and urine DPD respectively) and bone mineral parameters. BMD was measured by DXA scan.

RESULTS

Osteoporosis was seen in 44·7% of the postmenopausal women. Ethnicity specific reference ranges of BTMs were derived for the study population. Significant inverse correlation was found between all BTMs (except urine DPD) and BMD(P < 0·05). Daughters of mothers with osteoporosis at spine and femoral neck had lower BMD, compared to daughters of mothers without osteoporosis(P = 0·03 & 0·05).

CONCLUSION

Apart from deriving the ethnicity specific reference range for BTMs and finding a significant inverse correlation between BTM and BMD, this study found significantly lower BMD in daughters of mothers with osteoporosis at spine and femoral neck implicating the probable interplay of genetic, epigenetic and similar environmental factors.

Clinical usefulness of bone turnover marker concentrations in osteoporosis

Current evidence continues to support the potential for bone turnover markers (BTM) to provide clinically useful information particularly for monitoring the efficacy of osteoporosis treatment. Many of the limitations identified earlier remain, principally in regard to the relationship between BTM and incident fractures. Important data are now available on reference interval values for CTX and PINP across a range of geographic regions and for individual clinical assays. An apparent lack of comparability between current clinical assays for CTX has become evident indicating the possible limitations of combining such data for meta-analyses. Harmonization of units for reporting serum/plasma CTX (ng/L) and PINP (μg/L) is recommended. The development of international collaborations continues with an important initiative to combine BTM results from clinical trials in osteoporosis in a meta-analysis and an assay harmonization program are likely to be beneficial. It is possible that knowledge derived from clinical studies can further enhance fracture risk estimation tools with inclusion of BTM together with other independent risk factors. Further data of the relationships between the clinical assays for CTX and PINP as well as physiological and pre-analytical factors contributing to variability in BTM concentrations are required.

Establishment of reference intervals of clinical chemistry analytes for the adult population in Saudi Arabia: a study conducted as a part of the IFCC global study on reference values

Background:

This study is a part of the IFCC-global study to derive reference intervals (RIs) for 28 chemistry analytes in Saudis.

Method:

Healthy individuals (n=826) aged ≥18 years were recruited using the global study protocol. All specimens were measured using an Architect analyzer. RIs were derived by both parametric and non-parametric methods for comparative purpose. The need for secondary exclusion of reference values based on latent abnormal values exclusion (LAVE) method was examined. The magnitude of variation attributable to gender, ages and regions was calculated by the standard deviation ratio (SDR). Sources of variations: age, BMI, physical exercise and smoking levels were investigated by using the multiple regression analysis.

Results:

SDRs for gender, age and regional differences were significant for 14, 8 and 2 analytes, respectively. BMI-related changes in test results were noted conspicuously for CRP. For some metabolic related parameters the ranges of RIs by non-parametric method were wider than by the parametric method and RIs derived using the LAVE method were significantly different than those without it. RIs were derived with and without gender partition (BMI, drugs and supplements were considered).

Conclusions:

RIs applicable to Saudis were established for the majority of chemistry analytes, whereas gender, regional and age RI partitioning was required for some analytes. The elevated upper limits of metabolic analytes reflects the existence of high prevalence of metabolic syndrome in Saudi population.

Effect of simvastatin and atorvastatin on serum vitamin d and bone mineral density in hypercholesterolemic patients: a cross-sectional study

Background. Besides lipid-lowering effect of statins, they have been shown to have nonlipid lowering effects, such as improving bone health. An improvement in bone mineral density (BMD) has been indicated in some studies after the use of statins, in addition to an increase in 25-hydroxyvitamin D (25OHD) level. The aim of this study is to explore the association between statins and bone health taking into consideration 25OHD level and BMD. Methods. This is a randomized, cross-sectional comparative study. Subjects were divided into two groups, hypercholesterolemic participants taking simvastatin or atorvastatin as the study group and a matched control group not taking statins. All participants were assessed for serum 25OHD and BMD at lumbar spine and femoral neck. Results. A total of 114 participants were included in the study, 57 participants in each group. Results of serum 25OHD showed no significant difference between study and control groups (P = 0.47), while BMD results of lumbar spine and femoral neck showed significant difference (P = 0.05 and 0.03, resp.). Conclusion. Simvastatin and atorvastatin, at any dose for duration of more than one year, have no additive effect on 25OHD level but have a positive effect on the BMD.

Reference intervals of bone turnover markers determined by using their curve-fitting valley for adult females in China

SUMMARY

The reference values for bone turnover markers (BTMs) have a significant role in the diagnosis, monitoring, and treatment of metabolic bone disease. This study proposes that the peak value of bone mineral density and the trough value for the BTM curve can be used to determine the reference range of BTM.

INTRODUCTION

The aim of this study is to determine the reference intervals of BTMs for adult females in China with an attempt to reference the peak bone mineral density (BMD) with the corresponding BTM valley.

METHODS

This study included 546 premenopausal and 394 postmenopausal women. The levels of several BTMs were determined, and the BMD was measured using a dual-energy X-ray absorptiometry.

RESULTS

The BTMs of postmenopausal women were 17-96 % higher than premenopausal women. The change of BTM with age presented an optimal goodness-of-fit according to the cubic regression model (R (2) = 0.074-0.346, all P = 0.000). All kinds of BTM levels were positively correlated with age in premenopausal women aged 27-56 years old (r = 0.167-0.502, P = 0.023-0.000). Except for uCTX, the BTM reference value determined using a curve-fitting valley was significantly lower than the reference values for premenopausal women. The BTM reference values determined in this study were also significantly different from the reference values given by the manufacturers of the reagents used.

CONCLUSIONS

This study found that the changes of level with age of BTMs in Chinese women present an optimal goodness-of-fit according to the cubic regression model. The fitting valley corresponds to the BMD fitting peak and may possibly be an effective means of determining the BTM reference intervals.

Relationships between age-related biochemical markers of bone turnover and OPG, TGF-β1 and TGF-β2 in native Chinese women

Osteoprotegerin (OPG), transforming growth factor-β1 (TGF-β1) and TGF-β2 are cytokines closely associated with bone metabolism. However, their association with bone turnover markers in native Chinese women remains unknown. The study aims to investigate the relationship between bone metabolism related cytokines including OPG, TGF-β1, TGF-β2 and bone turnover markers in native Chinese women. The cross-sectional study was conducted on 691 healthy Chinese women (20-80 years old). Levels of OPG, TGF-β1, TGF-β2, serum bone-specific alkaline phosphatase (BAP), osteocalcin (OC), cross-linked N-terminal telopeptides of type I collagen (sNTX), cross-linked C-terminal telopeptides of type I collagen (sCTX), urinary NTX (uNTX), urinary CTX (uCTX) and total urinary deoxypyridinoline (uDPD) were determined. The present study showed that OPG and TGF-β2 had positive correlation with BAP, OC, uNTX, uCTX and uDPD, while TGF-β1 showed negative correlation with BAP, OC, sCTX, uNTX and uCTX, and most of the coefficients of partial correlation remained significant after adjustments for age and body mass index (BMI). Multiple linear regression stepwise analysis showed that OPG and TGF-β2 were positive determinative factors for BAP, sCTX, uNTX and uCTX, which could explain 0.6-16.6% of the variation in these markers. TGF-β1 was a negative determinative factor for BAP, OC, sCTX and uCTX, which could explain 0.7-7.3% of the variation in these markers. This study suggested that measuring bone turnover indicators and serum cytokines simultaneously might help evaluating changes in bone turnover rate caused by aging or menopause in women.

Reference intervals for serum concentrations of three bone turnover markers for men and women

OBJECTIVE

Bone turnover markers (BTMs) reflect the metabolic activity of bone tissue and can be used to monitor osteoporosis therapy. To adequately interpret BTMs, method-specific reference intervals are needed. We aimed to determine reference intervals for serum concentrations of intact amino-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BAP) and carboxy-terminal telopeptide of type I collagen (CTX).

MATERIAL AND METHODS

We established a healthy reference population of 1107 men as well as 382 pre- and 450 postmenopausal women, who participated in the first follow-up of the Study of Health in Pomerania. Serum PINP, BAP and CTX concentrations were measured on the IDS-iSYS Automated System (Immunodiagnostic Systems, Frankfurt am Main, Germany). The reference interval was defined as the central 95% range. We determined age-specific reference intervals for PINP, BAP, and CTX for men by quantile regression. Reference intervals for women were age-independent.

RESULTS

Reference intervals for men for PINP and CTX decreased with age (25-29year-old men: PINP 31.1-95.9ng/mL, CTX 0.12-0.83ng/mL; 75-79year-old men: PINP 15.7-68.1ng/mL, CTX 0.05-0.58ng/mL). The reference interval for men for BAP did not significantly change with age (25-29year-old men: 7.4-27.7ng/mL; 75-79year-old men: 7.6-24.4ng/mL). The reference intervals for 30-54year-old premenopausal women were: PINP 19.3-76.3ng/mL, BAP 6.0-22.7ng/mL, and CTX 0.05-0.67ng/mL. The reference intervals for 50-79year-old postmenopausal women were: PINP 18.2-102.3ng/mL, BAP 8.1-31.6ng/mL, and CTX 0.09-1.05ng/mL.

CONCLUSION

An intensively characterized, large reference population free of bone-related diseases allowed us to determine robust reference intervals for serum concentrations of PINP, BAP and CTX. Our normative data may aid to interpret bone turnover in adult men and pre- and postmenopausal women.

Study of the distribution by age group of serum cross-linked C-terminal telopeptide of type I collagen and procollagen type I N-propeptide in healthy Japanese women to establish reference values

Osteoporosis prevention is an important public health goal. Bone turnover markers are clinically measured to assess bone strength. C-terminal telopeptide of type I collagen (CTX) is released when collagens degrade and serves as an indicator of bone resorption. Simple CTX immunoassays are now available. However, serum CTX (sCTX) reference ranges for Japanese women are lacking. Procollagen type I N-propeptide (intact P1NP) reflects osteoblast activity, serving as a marker of bone formation. Because sCTX and intact P1NP are clinically applied as bone turnover markers, we determined reference ranges for both sCTX and intact P1NP in healthy Japanese women. We collected 228 blood samples from healthy Japanese women aged 19-83 years, grouped by age and menopausal status. We measured sCTX and intact P1NP and examined their correlation. sCTX values differed significantly between the two consecutive decade groups encompassing 19-39 years of age, intact P1NP values between 20 and 30 s, between post-menopausal 50 and 60 s, and between pre-and post-menopausal women in their 50 s. The mean sCTX of 91 healthy pre-menopausal women was 0.255 (0.100-0.653) ng/mL, the intact P1NP in 90 women 33.2 (17.1-64.7) μg/L. Corresponding values for post-menopausal women were 0.345 (0.115-1.030) ng/mL and 41.6 (21.9-79.1) μg/L. sCTX correlated with intact P1NP. Bone resorption markers are measured to assess anti-resorption agents, bone formation markers to assess the effects of bone-forming agents. The sCTX and intact P1NP reference values determined herein, in healthy Japanese women, are expected to be useful for osteoporosis treatment, assessment of fracture risk, and other clinical applications.

Increased serum sclerostin and decreased serum IGF-1 are associated with vertebral fractures among postmenopausal women with type-2 diabetes

Insulin-like growth factor 1 (IGF-1) is a determinant of bone mass and is inversely associated with vertebral fractures (VFs). Sclerostin regulates bone formation by inhibiting Wnt/β-catenin signaling. Currently, there is little information on circulating sclerostin levels among postmenopausal women with type-2 diabetes mellitus (T2DM) with VFs in relation to serum IGF-1 (s-IGF-1). We investigated the relationships between serum sclerostin, s-IGF-1, and VFs in postmenopausal women with T2DM. We assessed cross-sectionally 482 postmenopausal women with T2DM and 482 age-matched postmenopausal women without T2DM who were recruited at diabetic clinics and primary health care centers for inclusion in a bone health survey. The main outcome measures were serum sclerostin, s-IGF-1, bone mineral density (BMD), and bone turnover markers. Lateral X-rays of the thoracic and lumbar spine were taken to diagnose VFs. Serum sclerostin levels were increased, whereas s-IGF-1 levels were decreased when T2DM women were stratified by the number of VFs (P<0.0001). Multiple logistic regression analysis showed that serum sclerostin levels were positively associated with 1 VF (odds ratio [OR]=1.27, (95% CI:1.01-2.03), P=0.016), 2 VFs (OR=1.41, (95% CI:1.03-2.36), P=0.006), and ≥3 VFs (OR=1.54, (95% CI:1.12-2.44) P=0.005). s-IGF-1 levels were inversely associated with 1 VF (OR=0.58, (95% CI:0.39-0.88), P=0.041), 2 VFs (OR=0.42, (95% CI:0.21-0.90), P=0.012), and ≥3 VFs (OR=0.19, (95% CI: 0.14-0.27), P<0.001). Increased serum sclerostin and decreased s-IGF-1 were associated with VFs among postmenopausal women with T2DM, suggesting that sclerostin and/or IGF-1 may be involved in increased bone fragility in T2DM and could be potential markers of VF severity.

Bone remodelling is reduced by recovery from iron-deficiency anaemia in premenopausal women

Iron-deficiency anaemia (IDA), one of the most common and widespread health disorders worldwide, affects fundamental metabolic functions and has been associated with deleterious effects on bone. Our aim was to know whether there are differences in bone remodelling between a group of premenopausal IDA women and a healthy group, and whether recovery of iron status has an effect on bone turnover markers. Thirty-five IDA women and 38 healthy women (control group) were recruited throughout the year. IDA women received pharmacological iron treatment. Iron biomarkers, aminoterminal telopeptide of collagen I (NTx), procollagen type 1 N-terminal propeptide (P1NP), 25-hydroxyvitamin D, and parathormone (PTH) were determined at baseline for both groups and after treatment with pharmacological iron for the IDA group. IDA subjects were classified as recovered (R) or non-recovered (nR) from IDA after treatment. NTx levels were significantly higher (p <0.001), and P1NP levels tended to be lower in IDA women than controls after adjusting for age and body mass index (BMI), with no differences in 25-hydroxyvitamin D or PTH. After treatment, the R group had significantly lower NTx and P1NP levels compared to baseline (p <0.05 and p <0.001 respectively), whilst no significant changes were seen in the nR group. No changes were seen in 25-hydroxyvitamin D or PTH for either group. IDA is related to higher bone resorption independent of age and BMI. Recovery from IDA has a concomitant beneficial effect on bone remodelling in premenopausal women, decreasing both bone resorption and formation.

Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40) were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day). The animals were kept in individuals metabolic cages at a temperature of 24°±2ºC, light/dark cycles of 12/12 hours, and deionized water available ad libitum. On the 8th week of the experiment, food consumption was measured and 24-hour urine and 4-day feces were collected to determine calcium balance [Balance=Ca intake-(Urinary Ca+Fecal Ca)]. RESULTS: Animals with adequate calcium intake presented higher balances and rates of calcium absorption and retention (p<0.05) than those with inadequate calcium intake, regardless of caffeine intake (p<0.05). Caffeine intake did not affect urinary calcium excretion but increased balance (p<0.05) in the groups with adequate calcium intake. CONCLUSION: Adequate calcium intake attenuated the negative effects of estrogen deficiency and improved calcium balance even in the presence of caffeine.

Reference intervals for serum osteocalcin concentrations in adult men and women from the study of health in Pomerania

BACKGROUND

Osteocalcin (OC) is a bone-specific protein produced primarily by osteoblasts during bone formation. Besides its role in bone formation, osteocalcin may play a role in the regulation of energy metabolism and male fertility. To interpret serum OC data, reference intervals adapted to a specific laboratory method are needed.

METHODS

A healthy reference population was selected from the first follow-up of the Study of Health in Pomerania. Serum OC concentrations were measured with the IDS-iSYS N-Mid Osteocalcin assay on the IDS-iSYS Automated System (Immunodiagnostic Systems, Frankfurt am Main, Germany). The reference interval was defined as the central 95% range (2.5th-97.5th percentile). Age-specific reference intervals were calculated by quantile regression for 1107 men (25-79 years) and 545 premenopausal women (25-54 years). The reference interval for 498 postmenopausal women (50-79 years) was calculated irrespective of age.

RESULTS

Median (1st-3rd quartile) serum OC concentrations were 15.4 ng/mL (12.0-19.4 ng/mL) in men, 14.4 ng/mL (11.3-18.5 ng/mL) in premenopausal women, and 18.6 ng/mL (13.6-25.6 ng/mL) in postmenopausal women. Serum OC concentrations were highest in men and premenopausal women aged 25-29 years, were stable during midlife, and rose again after 65 years of age in men and at transition to menopause in women. Serum OC concentrations were lower in women taking oral contraceptives or who were under hormone replacement therapy after menopause and in subjects with diabetes mellitus or with body mass index < 18 or > 30 kg/m2 than in subjects without these conditions.

CONCLUSIONS

We established sex-specific adult reference intervals for the serum OC concentration measured by the IDS-iSYS N-Mid Osteocalcin assay.

Establishing reference intervals for bone turnover markers in the healthy shanghai population and the relationship with bone mineral density in postmenopausal women

The reference ranges of bone turnover markers (BTMs) were important during the treatment of osteoporosis, and the associations with bone mineral density (BMD) were controversial. The aim of this study was to establish the reference ranges of N-terminal procollagen of type l collagen (P1NP), osteocalcin (OC), and beta C-terminal cross-linked telopeptides of type I collagen ( β -CTX) in Shanghai area and to investigate the relationships between BTMs and BMD in postmenopausal women. 2,799 subjects recruited in Shanghai City were measured BTMs to establish the reference ranges. Additional 520 healthy postmenopausal women were also measured BTMs, these women measured BMD in addition. BTMs were measured using the Roche electrochemiluminescence system. We used the age range of 35 to 45-year-olds to calculate reference intervals. The reference range of OC was 4.91 to 13.90 ng/mL for women and 5.58 to 16.57 ng/mL for men, P1NP was 13.72 to 32.90 ng/mL for women and 16.89 to 42.43 ng/mL for men, and β -CTX was 0.112 to 0.210 ng/mL for women and 0.100 to 0.378 ng/mL for men. BTMs significantly negatively correlated with lumbar spine and femoral and total hip in postmenopausal women (Betastd = -0.157 ~ -0.217, P < 0.001). We established the normal reference ranges of P1NP, OC, and β -CTX in the Shanghai area. This study also found that BTMs correlated with BMD and suggested that BTMs were the key determining factors of early BMD decreases.

High serum sclerostin predicts the occurrence of osteoporotic fractures in postmenopausal women: the Center of Excellence for Osteoporosis Research Study

Sclerostin regulates bone formation by inhibiting Wnt pathway signaling. Low circulating sclerostin levels cause high bone mass. We hypothesized that postmenopausal women with increased sclerostin levels have a greater risk for osteoporosis-related fractures. We examined the association between circulating sclerostin together with bone turnover markers and osteoporosis-related fracture risk in 707 postmenopausal women, in a population-based study with a mean follow-up period of 5.2 ± 1.3 years. Multivariate Cox proportional hazards regression models were used to analyze fracture risk, adjusted for age, body mass index, and other confounding risk factors. High sclerostin levels were strongly associated with increased fracture risk. After adjustment for age and other confounders, the relative fracture risk was more than sevenfold among postmenopausal women for each 1-SD increment increase in sclerostin level. Women in the highest quartile of sclerostin levels had about a 15-fold increase in fracture risk. Results were similar when we compared sclerostin at the 1-year visit to an average of two to three annual measurements. Fracture risk attributable to sclerostin levels was 56.6% in the highest quartile. Only high levels of bone resorption markers (plasma cross-linked C-terminal telopeptide of type 1 collagen [p-CTx], urinary CTx [u-CTx], and urinary N-telopeptide of type 1 collagen [u-NTx]) were predictive of osteoporosis-related fractures but at much lower hazard ratio (HR) values than that of serum sclerostin. Associations between sclerostin levels and fracture risk were independent of bone mineral density and other confounding risk factors. High sclerostin levels are a strong and independent risk factor for osteoporosis-related fractures among postmenopausal women. © 2012 American Society for Bone and Mineral Research.

A global representation of vitamin D status in healthy populations

PURPOSE

This paper visualizes the available data on vitamin D status on a global map, examines the existing heterogeneities in vitamin D status and identifies research gaps.

METHODS

A graphical illustration of global vitamin D status was developed based on a systematic review of the worldwide literature published between 1990 and 2011. Studies were eligible if they included samples of randomly selected males and females from the general population and assessed circulating 25-hydroxyvitamin D [25(OH)D] levels. Two different age categories were selected: children and adolescents (1-18 years) and adults (>18 years). Studies were chosen to represent a country based on a hierarchical set of criteria.

RESULTS

In total, 200 studies from 46 countries met the inclusion criteria, most coming from Europe. Forty-two of these studies (21 %) were classified as representative. In children, gaps in data were identified in large parts of Africa, Central and South America, Europe, and most of the Asia/Pacific region. In adults, there was lack of information in Central America, much of South America and Africa. Large regions were identified for which the mean 25(OH)D levels were below 50 nmol/L.

CONCLUSIONS

This study provides an overview of 25(OH)D levels around the globe. It reveals large gaps in information in children and adolescents and smaller but important gaps in adults. In view of the importance of vitamin D to musculoskeletal growth, development, and preservation, and of its potential importance in other tissues, we strongly encourage new research to clearly define 25(OH)D status around the world.

Clusters within a wide spectrum of biochemical markers for osteoarthritis: data from CHECK, a large cohort of individuals with very early symptomatic osteoarthritis

OBJECTIVE

To assess a wide spectrum of biochemical markers (biomarkers) in a large cohort of individuals with (very) early symptomatic knee and/or hip osteoarthritis (OA). Secondly, to investigate associations between biomarkers and between biomarkers and demographics to demonstrate validity of the obtained dataset and further investigate the involvement and/or role of these biomarkers in OA.

DESIGN

Fourteen biomarkers (uCTX-II, uCTX-I, uNTX-I, sCOMP, sPIIANP, sCS846, sC1,2C, sOC, sPINP, sHA, sPIIINP, pLeptin, pAdiponectin, pResistin) were assessed by ELISA or RIA in CHECK (Cohort Hip and Cohort Knee), a 10-year prospective cohort of 1,002 individuals with early symptomatic knee and/or hip OA.

RESULTS

Quality controls revealed that gathered data were technically reliable. The majority of biomarkers showed relevant associations with demographic variables, which were expectedly different between genders and/or menopausal status for some. Principal component analysis enabled identification of five clusters, consecutively designated as 'bone-CTX-II', 'inflammation', 'synovium', 'C1,2C-adipokines', and 'cartilage synthesis' cluster. Notably, uCTX-II clustered with biomarkers of bone metabolism, while sCOMP clustered with biomarkers of synovial activity.

CONCLUSIONS

The identified clusters extended knowledge on individual biomarkers from mostly smaller studies as did the observed associations between biomarker levels and demographics, from which validity of our data was deduced. uCTX-II may not only reflect articular cartilage but also bone metabolism and sCOMP may reflect synovial rather than cartilage metabolism. Major involvement of adipokines in joint metabolism was not identified.

Decreased serum sclerostin levels in patients with primary hyperparathyroidism: a cross-sectional and a longitudinal study

Decreased serum sclerostin was evident in patients with primary hyperparathyroidism and was inversely related to parathyroid hormone (PTH). Sclerostin normalized earlier than biochemical bone turnover markers (BTMs) following parathyroidectomy.

INTRODUCTION

There is limited information on the changes of serum sclerostin in conditions with chronic PTH excess in humans. The main objectives of the present study were to: (1) examine cross-sectionally the changes of serum sclerostin levels in patients with primary hyperparathyroidism (PHPT), (2) study the time course changes in serum sclerostin in PHPT patients following parathyroidectomy (PTX) followed up longitudinally for 12 months, and (3) compare the changes in serum sclerostin to that of BTMs.

METHODS

We studied 60 PHPT patients and compared them with 74 PTX patients together with 268 age- and sex-matched healthy controls. Also, we followed 27 PTX patients longitudinally at 2, 4, 6, 10, 30, 60, 180, and 360 days postoperatively. Serum sclerostin, BTMs, and minerals were measured. Also, bone mineral density was determined by dual energy X-ray absorptiometry.

RESULTS

Patients with PHPT exhibited significantly lower mean serum sclerostin [mean, in picomoles per liter; 95% confidence interval (CI)] (28.98; 27.94-30.03) than that obtained for PTX patients (37.01; 35.75-38.27) and healthy controls (46.22; 45.13-47.31) (P < 0.0001, for each case), respectively. Serum PTH inversely correlated with serum sclerostin (r = -0.651, P < 0.0001). Serum sclerostin was normalized in PTX patients by the tenth day postoperatively and remained within the expected reference range thereafter.

CONCLUSIONS

Significantly decreased serum sclerostin was evidenced in PHPT patients as compared with PTX and euparathyroid controls. The inverse PTH and sclerostin relationship suggests that sclerostin is downregulated by PTH in humans. Serum sclerostin normalized earlier than BTMs following parathyroidectomy.

Diagnostic performance of the urinary deoxypyridinoline in spinal tuberculosis

This study investigated the diagnostic significance of urinary deoxypyridinoline measurement as a screening tool for spinal tuberculosis in patients with pulmonary tuberculosis.Urinary deoxypyridinoline levels were measured by automated chemiluminescence immunoassay and automated chemistry methods in patients with spinal (n=33) and pulmonary tuberculosis (n=33) and in healthy controls (n=30). Urinary deoxypyridinoline was divided by urinary creatine to exclude the factors of body mass index and urine dilution. The results underwent validity analysis. The measurements of urinary deoxypyridinoline in the spinal tuberculosis, pulmonary tuberculosis, and control groups were 14.9 ± 9.8, 6.4 ± 2.6, and 6.3 ± 2.0 μmol/molCr, respectively. Compared with the other 2 groups, the urinary deoxypyridinoline level in the spinal tuberculosis group was significantly increased (P=.001 and P=.000, respectively). However, urinary deoxypyridinoline levels were not significantly different between the pulmonary tuberculosis and control groups (P=.751). The receiver operating characteristic curve in the spinal tuberculosis group was 0.83. For deoxypyridinoline, the sensitivity (88%) and specificity (95%) were seen at the cutoff level of 8.0 μmol/molCr. The false positive and false negative were 12% and 5%, respectively. Diagnostic validity of the method was 93%.Bone metabolism alteration occurs during the progression of spinal tuberculosis, which can be reflected by the sensitivity and specificity of urinary deoxypyridinoline. The detection of urinary deoxypyridinoline is a benefit of screening patients with pulmonary tuberculosis for spinal tuberculosis.

Relationship between vitamin D deficiency, bone remodelling and iron status in iron-deficient young women consuming an iron-fortified food

BACKGROUND

Iron and vitamin D deficiencies are two of the most widespread nutritional disorders in the world. Our aim was to know whether the consumption of an iron-fortified fruit juice modifies bone remodelling and the possible influence of baseline vitamin D status on the recovery of iron status in a group of iron-deficient women.

METHODS

Iron biomarkers, 25-hydroxyvitamin D levels and dietary intake were measured in 123 iron-deficient menstruating women. A subgroup (n = 41) participated in a randomised double-blind placebo-controlled study of 16-weeks during winter. They consumed a placebo fruit juice (P) or iron-fortified fruit juice (F). Dietary intake, 25-hydroxyvitamin D, parathormone (PTH), bone alkaline phosphatase (ALP), aminoterminal telopeptide of collagen I (NTX) and iron biomarkers were determined.

RESULTS

Ninety-two per cent of the iron-deficient women were vitamin D deficient or insufficient. Transferrin saturation and 25-hydroxyvitamin D were positively correlated. Iron status improved in F, 25-hydroxyvitamin D decreased in F and P, and PTH, ALP and NTX levels were within the normal range and did not vary. Women with 25-hydroxyvitamin D ≥ 50 nmol/L compared with 25-hydroxyvitamin D < 50 nmol/L showed a higher increase in transferrin saturation (a marker of iron supply to tissues) during iron recovery.

CONCLUSION

The prevalence of vitamin D deficiency or insufficiency is very high in iron-deficient women. The recovery of iron status by consuming an iron-fortified food does not affect 25-hydroxyvitamin D levels; however, the increase in iron supply to tissues is lower if the women also present vitamin D deficiency. Although bone health does not seem to be affected in this group of women, correction of iron and vitamin D deficiencies should be promoted in young women to improve present and future health.

Measurement of C-terminal telopeptide of type I collagen (CTX) in serum

Serum CTX assays measure a fragment of the C-terminal telopeptide of type 1 collagen released during resorption of mature bone. Assay reagents are available in manual and automated formats and give good analytical performance. However their standardisation is not transparent and significant differences in results between methods have been demonstrated. CTX is most stable in EDTA plasma, although serum samples processed promptly would be satisfactory. sCTX shows a profound circadian rhythm, especially in non-fasting subjects; specimens should be collected from fasting patients at a well-defined time of day to minimise biological variation. Reference intervals in pre-menopausal women have been well studied but in other adult groups there is less information. Healthy children show the expected age-related variation corresponding to growth rate. Serum CTX fulfils or partially fulfils all the criteria of a reference bone turnover marker. Further studies aimed at reducing inter-method differences in results and establishing the relationships of sCTX with fracture risk and with fracture risk improvement with treatment are required.

Role of serum FSH measurement on bone resorption in postmenopausal women

In vitro and animals models have shown follicle-stimulating hormone (FSH) effects on osteoclastic function, and FSH levels seem to influence bone loss independently of estrogen concentrations in humans. Our aim was to evaluate the role of serum FSH measurement in the assessment of bone resorption in postmenopausal women. We conducted a cross-sectional study including 92 postmenopausal healthy women aged 56.2 (3.6) and 7.2 (4) years since menopause. Serum FSH, luteinizing hormone (LH), estradiol (E2) and bone turnover markers as osteocalcin (OC) and C-terminal telopeptide of type I collagen (CTX) were measured. We analyzed the relationship between serum levels of gonadotropins, E2, and bone turnover markers. Serum levels of OC and CTX were positively related to FSH (r = 0.234, P = 0.047 and r = 0.384, P = 0.003) and LH (r = 0.319, P = 0.012 and r = 0.273, P = 0.038). There was no relationship with E2 levels. When gonadotropins levels were divided into quartiles, we found significant differences in bone turnover markers between the first and the fourth quartile. OC levels were higher in the highest quartile of FSH (P = 0.024) and LH (P = 0.001). Serum CTX was also higher in the highest quartile of FSH (P = 0.004) and LH (P = 0.039). FSH levels could explain approximately 14.7% of the chances in CTX. In summary, gonadotropins were related to bone turnover in postmenopausal healthy women. Moreover, the rise in FSH appears to contribute to higher bone resorption. Our results suggest that the measurement of FSH could be usefulness to perform a more comprehensive assessment of bone loss in these women.