Associations of hemoglobin and change in hemoglobin with risk of incident hip fracture in older men and women: the cardiovascular health study

Anemia as a mediator: bridging the frailty index and hip fractures in older Chinese populations

Background

Hip fracture is a significant global public health issue. The link and mechanisms between frailty index (FI) and hip fracture remain unclear. This research examined how anemia mediates the link between FI and hip fracture.

Methods

The study analyzed data from the 2015 China Health and Retirement Longitudinal Study (CHARLS), which included 6,326 participants aged 60 and above. The mediating role of anemia in the relationship between FI and hip fracture was examined using bootstrap analysis and linear regression models.

Results

After controlling for confounding variables, FI was positively associated with hip fracture (OR = 1.13, 95% CI: 1.09-1.16; p < 0.001). Anemia was also positively associated with hip fracture (OR = 1.88, 95% CI: 1.33-2.64; p < 0.001). Mediation analysis showed that anemia indirectly affected the relationship between FI and hip fracture, accounting for 18.95% of the total effect. Subgroup analysis showed that compared with non-frail and non-anemic participants, frail and anemic participants had a significantly increased risk of hip fracture (OR = 4.61, 95% CI: 2.80-7.61). However, no interaction between frailty and anemia was observed for hip fracture risk.

Conclusions

The findings suggest that FI and anemia were positively associated with hip fracture, and anemia played a mediating role in the association between FI and hip fracture. Intervention based on exercise, nutrition and medical management can combat anemia and reduce FI and may be an effective way to prevent or delay hip fractures.

Exploring the pathophysiology of anemia in COPD: Insights from chest CT and longitudinal clinical data

BACKGROUND

Although anemia has been associated with chronic obstructive pulmonary disease (COPD) severity, the underlying risk factors, such as chest imaging indicators, remain poorly understood. In this study, we aimed to investigate the relationship between anemia and clinical features, including pulmonary and extrapulmonary indicators on chest computed tomography (CT), and to clarify the pathophysiology of anemia in COPD.

METHODS

A total of 400 patients with COPD were prospectively followed for 3 years. Anemia was defined as hemoglobin <13 g/dl in males and <12 g/dl in females. Patients were categorized into the anemia and non-anemia groups, and their clinical characteristics were compared.

RESULTS

The anemia group exhibited lower percentage of predicted forced expiratory volume in 1 s (%FEV1) and body mass index (BMI) measurements, worse COPD assessment test (CAT) scores, and more frequent exacerbations. Imaging revealed more severe emphysema, lower cross-sectional areas of the pectoralis and erector spinae muscles, decreased subcutaneous fat, and more severe coronary artery calcification in this group. Additionally, echocardiography demonstrated a higher prevalence of pulmonary hypertension and reduced left ventricular ejection fraction in patients with anemia. Three-year longitudinal data analysis further showed that declining hemoglobin levels correlated with the worsening of nutritional status, a deterioration in bone mineral density (BMD), and an increase in CAT scores.

CONCLUSION

Anemia in COPD is a multifactorial comorbidity resulting in emphysema, decreased fat and muscle mass, and reduced BMD.

Association between serum albumin with geriatric nutritional risk index and osteopenia in Chinese elderly men: a nested case-control study

BACKGROUND AND OBJECTIVES

Malnutrition is associated with a higher risk of osteoporosis. We aim to assess the relationship between serum albumin with geriatric nutritional risk index and osteopenia in Chinese elderly men.

METHODS AND STUDY DESIGN

This is a nested case-control study from a prospective cohort enrolled 1109 individuals who were followed for seven years. Demographic data, medical history, signs and symptoms, and laboratory parameters were collected and analysed. Nutritional status and Geriatric Nutritional Risk Index (GNRI) were assessed. The nutrition-related indexes predictive value for osteopenia development was analyzed through multivariate Cox regression analysis and by creating a receiver operating characteristic curve (ROC), calculating the area under the curve (AUC). Kaplan-Meier (K-M) method was further used to find the nutritional status level in the elderly men.

RESULTS

The ALB and GNRI correlated with the risk of osteopenia in Chinese elderly men. After adjusting for all covariates, people with higher ALB level (HR: 0.821; 95% CI: 0.790-0.852) and higher GNRI score (HR: 0.889; 95% CI: 0.869-0.908) had a smaller risk of osteopenia. ROC analysis showed that the AUC for ALB was 0.729 (p<0.05) and for the GNRI score was 0.731 (p<0.05). K-M curve indicated a significant difference in ALB level (p<0.001) and GNRI score (p<0.001) in the respective subgroups.

CONCLUSIONS

This study found that lower ALB level and lower GNRI score are associated with a higher prevalence of osteopenia among elderly men in China.

Gender differences in the association between anemia and osteoporosis: findings from a large-scale prospective analysis

PURPOSE

Osteoporosis (OP) is characterized by a gradual onset and an increased susceptibility to osteoporotic fractures. Previous retrospective studies have suggested that hemoglobin (HGB) levels could be a potential diagnostic marker for OP. However, the relationship between OP and anemia remains uncertain. This prospective study aimed to investigate the association between HGB levels and OP.

METHODS

Leveraging data from the UK Biobank, a cohort of 452 778 individuals was analyzed. Employing a modified Cox proportional hazards model that accounted for sociodemographic factors, lifestyle, and health-related factors, we examined the links between incident OP and sex. Moreover, we investigated the impact of OP with or without a pathological fracture.

RESULTS

Following a median follow-up period of 5.85 years, 4294 participants were diagnosed with OP. After adjusting for a comprehensive range of pertinent confounders, individuals with anemia exhibited a 2.15-fold higher risk of OP in males and a 1.41-fold higher risk in females. Moreover, each unit increase in HGB concentration corresponded to a 0.83-fold decrease in OP risk for men and a 0.94-fold decrease for women.

PERSPECTIVES

Our findings reveal a significant correlation between HGB levels or anemia and OP, with males demonstrating a greater susceptibility compared to females. The risk of OP decreased with higher HGB concentrations in both sexes, although this effect was more pronounced in males. It is recommended to conduct longitudinal studies to investigate the causality of the observed connections and experimental studies to understand the underlying mechanisms.

Analysis of the risk factors for contralateral refracture after hip fracture surgery in elderly individuals: a retrospective study

BACKGROUND

The risk factors for contralateral hip refracture after primary hip fracture are not fully understood; therefore, this study compared the clinical characteristics of patients with first and second hip fractures and explored and analyzed the risk factors for contralateral refracture after hip fracture in elderly individuals to provide a reference for the clinical prevention of postoperative refracture of hip fracture in elderly individuals.

METHODS

A retrospective study was conducted on 458 elderly patients with hip fractures who underwent surgical treatment and were discharged from our hospital from March 2016 to March 2019. The clinical data of the patients were analyzed retrospectively. Patients were divided into a case group (postoperative refracture) and a control group (no postoperative refracture) based on whether they experienced refracture within five years after surgery. The clinical data of the two groups were compared and analyzed via univariate and multivariate logistic regression analyses and receiver operating characteristic (ROC) regression analysis to identify the risk factors for refractures after hip fracture surgery in elderly patients.

RESULTS

Sixty-one patients experienced refracture, with an incidence rate of 13.3%. Age ≥ 80.5 years, female sex, poor knee joint function, FRAX score ≥ 15.5, anemia, visual impairment, osteoporosis, and Alzheimer's disease (AD) were identified as risk factors for refracture after hip fracture surgery in elderly individuals (P < 0.05).

CONCLUSION

Elderly patients with hip fractures are susceptible to refracture after surgery because of factors such as advanced age, female sex, high FRAX score, poor knee joint function, anemia, osteoporosis, visual impairment, and AD. Targeted interventions should be implemented based on the above risk factors.

Sex differences in hemoglobin levels and five-year refracture risk in patients with osteoporotic fractures: a retrospective cohort analysis

We conducted a retrospective cohort analysis to examine the association between hemoglobin (Hb) levels and refracture risk in elderly patients with osteoporotic fractures (OPFs). Our findings suggest a nonlinear relationship exists in females, and females with Hb levels below 10.7 g/dL may be at a higher risk of refracture.

INTRODUCTION

Hematopoiesis and bone health have a reciprocal influence on each other. Nevertheless, there is a scarcity of in-depth research on the association between Hb levels and the occurrence of fractures. The present research aimed to investigate the correlation between Hb levels and the rate of refracture within 5 years among individuals with OPFs.

METHODS

A retrospective cohort analysis was undertaken between 2017 and 2022. The study included 1906 individuals who were inhabitants of Kunshan and were over 60 years old. These individuals had experienced an OPF between January 1, 2017, and July 27, 2022, resulting in their hospitalization. Cox proportional hazard regression models were used to evaluate the risk of refracture within 5 years based on the Hb levels acquired during the admission examination, with consideration for sex differences. A nonlinear relationship was identified using smoothed curve fitting and threshold analysis. Kaplan-Meier curves were used to compare refracture rates between patients with low and high Hb levels.

RESULTS

Elderly female patients with OPFs and lower Hb levels exhibited a significantly higher risk of a 5-year refracture. Conversely, no significant associations were observed between the two variables in male patients. A nonlinear correlation was found between Hb levels and the probability of refracture in females, with a turning point identified at 10.7 g/dL of Hb levels. A strong negative association was observed with the five-year refracture rate when Hb levels fell below 10.7 g/dL (hazard ratio (HR) = 0.63; 95% confidence interval (CI) 0.48 to 0.83; P-value = 0.0008). This finding suggests that for every 1 g/dL increase in Hb below 10.7 g/dL, the risk of refracture reduced by 37%. However, no statistically significant association was observed when Hb levels were above 10.7 g/dL.

CONCLUSIONS

The findings demonstrated a significant negative correlation between Hb levels and the likelihood of refracture in elderly female patients with OPFs and suggested that elderly females with recent OPFs and Hb levels below 10.7 g/dL may be at a higher risk of refracture. Additionally, the Hb levels can serve as an indicator of bone fragility in elderly female patients with OPFs. These findings highlight the importance of monitoring Hb levels as a part of comprehensive management strategies to both assess skeletal health and prevent refractures in this population.

Development and internal validation of a clinical prediction model for osteopenia in Chinese middle-aged and elderly men: a prospective cohort study

BACKGROUND

Early identification of patients at risk of osteopenia is an essential step in reducing the population at risk for fractures. We aimed to develop and validate a prediction model for osteopenia in Chinese middle-aged and elderly men that provides individualized risk estimates.

METHODS

In this prospective cohort study, 1109 patients who attend regular physical examinations in the Second Medical Centre of Chinese PLA General Hospital were enrolled from 2015.03 to 2015.09. The baseline risk factors included dietary habits, exercise habits, medical histories and medication records. Osteopenia during follow-up were collected from Electronic Health Records (EHRs) and telephone interviews. Internal validation was conducted using bootstrapping to correct the optimism. The independent sample T-test analysis, Mann_Whitney U test, Chi-Square Test and multivariable Cox regression analysis were utilized to identify predictive factors for osteopenia in Chinese middle-aged and elderly men. A nomogram based on the seven variables was built for clinical use. Concordance index (C-index), receiver operating characteristic curve (ROC), decision curve analysis (DCA) and calibration curve were used to evaluate the efficiency of the nomogram.

RESULTS

The risk factors included in the prediction model were bone mineral density at left femoral neck (LNBMD), hemoglobin (Hb), serum albumin (ALB), postprandial blood glucose (PBG), fatty liver disease (FLD), smoking and tea consumption. The C-index for the risk nomogram was 0.773 in the prediction model, which presented good refinement. The AUC of the risk nomogram at different time points ranged from 0.785 to 0.817, exhibiting good predictive ability and performance. In addition, the DCA showed that the nomogram had a good clinical application value. The nomogram calibration curve indicated that the prediction model was consistent.

CONCLUSIONS

Our study provides a novel nomogram and a web calculator that can effectively predict the 7-year incidence risk of osteopenia in Chinese middle-aged and elderly men. It is convenient for clinicians to prevent fragility fractures in the male population.

PTH and the Regulation of Mesenchymal Cells within the Bone Marrow Niche

Parathyroid hormone (PTH) plays a pivotal role in maintaining calcium homeostasis, largely by modulating bone remodeling processes. Its effects on bone are notably dependent on the duration and frequency of exposure. Specifically, PTH can initiate both bone formation and resorption, with the outcome being influenced by the manner of PTH administration: continuous or intermittent. In continuous administration, PTH tends to promote bone resorption, possibly by regulating certain genes within bone cells. Conversely, intermittent exposure generally favors bone formation, possibly through transient gene activation. PTH's role extends to various aspects of bone cell activity. It directly influences skeletal stem cells, osteoblastic lineage cells, osteocytes, and T cells, playing a critical role in bone generation. Simultaneously, it indirectly affects osteoclast precursor cells and osteoclasts, and has a direct impact on T cells, contributing to its role in bone resorption. Despite these insights, the intricate mechanisms through which PTH acts within the bone marrow niche are not entirely understood. This article reviews the dual roles of PTH-catabolic and anabolic-on bone cells, highlighting the cellular and molecular pathways involved in these processes. The complex interplay of these factors in bone remodeling underscores the need for further investigation to fully comprehend PTH's multifaceted influence on bone health.

Development and validation of a predictive nomogram for subsequent contralateral hip fracture in elderly patients within 2 years after hip fracture surgery

Purpose

Contralateral hip refracture following initial hip fracture surgery is life-threatening in the elderly with high incidence and mortality. This study investigated the associated independent risk factors and established a nomogram prediction model.

Methods

Totally 734 elderly patients with hip fractures who underwent surgical treatment (January 2016-December 2020) were enrolled. Following analyses on demographic variables, clinical characteristics, and laboratory examination, independent risk factors of contralateral hip fractures in the elderly were identified through the least absolute shrinkage and selection operator (LASSO) regression, and univariate and multivariate logistic regression. Patients were randomly allocated into training (n = 513) and validation sets (n = 221). A training set-based nomogram prediction model was established and assessed for predictability, discriminatory ability, and clinical applicability using the receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA) in both sets.

Results

Contralateral hip refractures occurred in 7.08% (52/734) patients within 2 years after surgery. Age, hemoglobin (Hb), heart disease, neurovascular disease, Parkinson's disease (PD), Alzheimer's disease (AD), chronic obstructive pulmonary disease (COPD), and chronic kidney disease (CKD) were independent risk factors. The nomogram prediction model had a favorable discriminatory ability, as indicated by the areas under the ROC curves (AUC): 0.906 (95% CI, 0.845-0.967) in the training set and 0.956 (95% CI, 0.927-0.985) in the validation set. The calibration curves demonstrated a good consistency between the actual subsequent contralateral hip fracture incidence and the predicted probability. The DCA of the nomogram demonstrated the model's excellent clinical efficacy.

Conclusion

The nomogram model enabled accurate individualized prediction for the occurrence of subsequent contralateral hip fracture in the elderly within 2 years after surgical treatment, which might help clinicians with precise references for appropriate perioperative management and rehabilitation education following initial hip surgery for their patients.

Hemoglobin Levels Improve Fracture Risk Prediction in Addition to FRAX Clinical Risk Factors and Bone Mineral Density

CONTEXT

Anemia and decreasing levels of hemoglobin (Hb) have previously been linked to increased fracture risk, but the added value to FRAX, the most utilized fracture prediction tool worldwide, is unknown.

OBJECTIVE

To investigate the association between anemia, Hb levels, bone microstructure, and risk of incident fracture and to evaluate whether Hb levels improve fracture risk prediction in addition to FRAX clinical risk factors (CRFs).

METHODS

A total of 2778 community-dwelling women, aged 75-80 years, and part of a prospective population-based cohort study in Sweden were included. At baseline, information on anthropometrics, CRFs, and falls was gathered, blood samples were collected, and skeletal characteristics were investigated using dual-energy x-ray absorptiometry and high-resolution peripheral quantitative computed tomography. At the end of follow-up, incident fractures were retrieved from a regional x-ray archive.

RESULTS

The median follow-up time was 6.4 years. Low Hb was associated with worse total hip and femoral neck bone mineral density (BMD), and lower tibia cortical and total volumetric BMD, and anemia was associated with increased risk of major osteoporotic fracture (MOF; hazard ratio 2.04; 95% CI 1.58-2.64). Similar results were obtained for hip fracture and any fracture, also when adjusting for CRFs. The ratio between 10-year fracture probabilities of MOF assessed in models with Hb levels included and not included ranged from 1.2 to 0.7 at the 10th and 90th percentile of Hb, respectively.

CONCLUSION

Anemia and decreasing levels of Hb are associated with lower cortical BMD and incident fracture in older women. Considering Hb levels may improve the clinical evaluation of patients with osteoporosis and the assessment of fracture risk.

Osteoblast Lineage Support of Hematopoiesis in Health and Disease

In mammals, hematopoiesis migrates to the bone marrow during embryogenesis coincident with the appearance of mineralized bone, where hematopoietic stem cells (HSCs) and their progeny are maintained by the surrounding microenvironment or niche, and sustain the entirety of the hematopoietic system. Genetic manipulation of niche factors and advances in cell lineage tracing techniques have implicated cells of both hematopoietic and nonhematopoietic origin as important regulators of hematopoiesis in health and disease. Among them, cells of the osteoblast lineage, from stromal skeletal stem cells to matrix-embedded osteocytes, are vital niche residents with varying capacities for hematopoietic support depending on stage of differentiation. Here, we review populations of osteoblasts at differing stages of differentiation and summarize the current understanding of the role of the osteoblast lineage in supporting hematopoiesis. © 2022 American Society for Bone and Mineral Research (ASBMR).

Relationship between indices of circulating blood cells and bone homeostasis in osteoporosis

Bone development have been shown to play an important role in regulating hematopoiesis as one major component of bone marrow microenvironment. Recent studies support the notion that there is an intricate relationship between hematopoiesis and bone homeostasis, however, little is known about the alterations in the hematopoietic lineages in pathologic conditions. Using various osteoporotic mouse models, we show here that bone microarchitecture abnormalities alter parameters of peripheral blood cells. The level of white blood cells is dynamics and negatively correlated with bone mineral density during the progression of osteoporosis. Furthermore, our clinical data confirm that osteoporosis is associated with abnormal circulating blood cell counts. These results demonstrated a causal link that osteoporosis is accompanied by the altered circulating blood cells, supporting the idea of a close interplay between hematopoiesis and bone homeostasis. Our study would propose that routine complete blood count might be applied as a potential diagnostic and putative marker for osteoporosis.