Alzheimer's Disease is an Important Risk Factor of Fractures: a Meta-analysis of Cohort Studies

Feasibility of Identifying Factors Related to Alzheimer's Disease and Related Dementia in Real-World Data

A comprehensive view of factors associated with AD/ADRD will significantly aid in studies to develop new treatments for AD/ADRD and identify high-risk populations and patients for prevention efforts. In our study, we summarized the risk factors for AD/ADRD by reviewing existing meta-analyses and review articles on risk and preventive factors for AD/ADRD. In total, we extracted 477 risk factors in 10 categories from 537 studies. We constructed an interactive knowledge map to disseminate our study results. Most of the risk factors are accessible from structured Electronic Health Records (EHRs), and clinical narratives show promise as information sources. However, evaluating genomic risk factors using RWD remains a challenge, as genetic testing for AD/ADRD is still not a common practice and is poorly documented in both structured and unstructured EHRs. Considering the constantly evolving research on AD/ADRD risk factors, literature mining via NLP methods offers a solution to automatically update our knowledge map.

Dementia, osteoporosis and fragility fractures: Intricate epidemiological relationships, plausible biological connections, and twisted clinical practices

Dementia, osteoporosis, and fragility fractures are chronic diseases, often co-existing in older adults. These conditions pose severe morbidity, long-term disability, and mortality, with relevant socioeconomic implications. While in the research arena, the discussion remains on whether dementia is the cause or the consequence of fragility fractures, healthcare professionals need a better understanding of the interplay between such conditions from epidemiological and physiological standpoints. With this review, we summarized the available literature surrounding the relationship between cognitive impairment, dementia, and both low bone mineral density (BMD) and fragility fractures. Given the strength of the bi-directional associations and their impact on the quality of life, we shed light on the biological connections between brain and bone systems, presenting the main mediators, including gut microbioma, and pathological pathways leading to the dysregulation of bone and brain metabolism. Ultimately, we synthesized the evidence about the impact of available pharmacological treatments for the prevention of fragility fractures on cognitive functions and individuals' outcomes when dementia coexists. Vice versa, the effects of symptomatic treatments for dementia on the risk of falls and fragility fractures are explored. Combining evidence alongside clinical practice, we discuss challenges and opportunities related to the management of older adults affected by cognitive impairment or dementia and at high risk for fragility fracture prevention, which leads to not only an improvement in patient health-related outcomes and survival but also a reduction in healthcare cost and socio-economic burden.

Alzheimer's disease and its associated risk of bone fractures: a narrative review

Background

Alzheimer's disease (AD) is a neurodegenerative disorder that is the major cause of dementia in the aged population. Recent researches indicate that patients with AD have a significantly increased fracture risk, but the pathological mechanisms are still unclear.

Objective

We systematically reviewed studies regarding bone fracture risk in AD to uncover links between the pathologies of osteoporosis and AD.

Methods

We searched the literature using the databases of PubMed, Web of Science, Embase and Cochrane Library. Studies were included if they evaluated bone fracture risk in AD patients and if they explored the pathogenesis and prevention of bone fractures in these patients.

Results

AD patients had a significantly higher risk of bone fractures than age-matched controls. Multiple factors contributed to the increased risk of bone fractures in AD patients, including the direct effects of amyloid pathology on bone cells, abnormal brain-bone interconnection, Wnt/β-catenin signalling deficits, reduced activity, high risk of falls and frailty, and chronic immune activity. Exercise, prevention of falls and fortified nutrition were beneficial for reducing the fracture risk in AD patients. However, the efficacy of anti-osteoporotic agents in preventing bone fractures should be further evaluated in AD patients as corresponding clinical studies are very scarce.

Conclusion

Alzheimer's disease patients have increased bone fracture risk and decreased bone mineral density owing to multiple factors. Assessment of anti-osteoporotic agents' efficacy in preventing bone fractures of AD patients is urgently needed.

Increased risk of dementia among people with a history of fractures: a systematic review and meta-analysis of population-based studies

Background

Emerging evidence suggests that there may be an association between a history of fractures and dementia risk, but the epidemiological findings are inconsistent. We, therefore, conducted a meta-analysis to systematically assess the risk of dementia among people with a history of fractures.

Methods

We comprehensively searched four electronic databases (PubMed, Web of Science, Embase, and Cochrane Library) for relevant literature published from inception to 10 January 2023. Longitudinal observational studies that investigated the association between any type of fracture occurrence and the subsequent risk of dementia were included for qualitative and quantitative analysis. Risk estimates were pooled using fixed-effects or random-effects models according to the level of heterogeneity. The Newcastle-Ottawa scale was used to evaluate the risk of bias in the included studies.

Results

A total of seven population-based studies involving 3,658,108 participants (136,179 with a history of fractures) were eventually included. Pooled results showed a significant association between fracture and subsequent risk of dementia [hazard ratio (HR) = 1.28, 95% confidence interval (CI): 1.11-1.48] in cohort studies. Patients with fractures at different sites showed a similar trend toward increased risk of subsequent dementia. No gender, age, region, duration of follow-up, study quality, or study design specificity were observed. Sensitivity analysis indicates that the current results are robust. No publication bias existed. The results were similar in the cohort study with the standardized incidence ratio (SIR) as the statistical measure (SIR = 1.58, 95% CI: 1.25-2.00) and in the case-control study (OR = 1.38, 95% CI: 1.18-1.61). Of note, the causal relationship between fracture and dementia was not demonstrated in this meta-analysis.

Conclusion

People with a history of fractures are at increased risk of developing dementia. Enhanced screening and preventive management of dementia in people with a history of fractures may be beneficial.

Unfavorable effects of memantine on the skeletal system in female rats

Memantine is an N-methyl-D-aspartate (NMDA) receptor antagonist used in the treatment of Alzheimer's disease (AD). NMDA receptors are expressed on bone cells. The aim of the present study was to investigate the effects of memantine on the rat musculoskeletal system. Taking into account that most of female AD patients are postmenopausal, the study was carried out on intact and ovariectomized (estrogen-deficient) rats. Mature Wistar rats were divided into following groups: non-ovariectomized (NOVX) control rats, NOVX rats treated with memantine, ovariectomized (OVX) control rats, and OVX rats treated with memantine. Memantine (2 mg/kg p.o.) was administered once daily for four weeks, starting one week after ovariectomy. The serum bone turnover marker and cytokine levels, bone density, mass, mineralization, mechanical properties, histomorphometric parameters of compact and cancellous bone, skeletal muscle mass and grip strength were determined. In NOVX rats, memantine slightly decreased the strength of compact bone of the femoral diaphysis (parameters in the yield point) and unfavorably affected histomorphometric parameters of cancellous bone (the femoral epiphysis and metaphysis). In OVX rats, in which estrogen deficiency induced osteoporotic changes, memantine increased the phosphorus content in the femoral bone mineral. No other effects on bone were observed in the memantine-treated OVX rats. In conclusion, the results of the present study indicated slight damaging skeletal effects of memantine in rats with normal estrogen levels.

Effects of Donepezil on the Musculoskeletal System in Female Rats

The extension of human life makes it more and more important to prevent and treat diseases of the elderly, including Alzheimer's disease (AD) and osteoporosis. Little is known about the effects of drugs used in the treatment of AD on the musculoskeletal system. The aim of the present study was to investigate the effects of donepezil, an acetylcholinesterase inhibitor, on the musculoskeletal system in rats with normal and reduced estrogen levels. The study was carried out on four groups of mature female rats: non-ovariectomized (NOVX) control rats, NOVX rats treated with donepezil, ovariectomized (OVX) control rats and OVX rats treated with donepezil. Donepezil (1 mg/kg p.o.) was administered for four weeks, starting one week after the ovariectomy. The serum concentrations of CTX-I, osteocalcin and other biochemical parameters, bone mass, density, mineralization, histomorphometric parameters and mechanical properties, and skeletal muscle mass and strength were examined. Estrogen deficiency increased bone resorption and formation and worsened cancellous bone mechanical properties and histomorphometric parameters. In NOVX rats, donepezil decreased bone volume to tissue volume ratio in the distal femoral metaphysis, increased the serum phosphorus concentration and tended to decrease skeletal muscle strength. No significant bone effects of donepezil were observed in OVX rats. The results of the present study indicate slightly unfavorable effects of donepezil on the musculoskeletal system in rats with normal estrogen levels.

Impact of Dementia on Long-Term Hip Fracture Surgery Outcomes: An Electronic Health Record Analysis

OBJECTIVE

Older adults with dementia are at higher risk for sustaining hip fracture and their long-term health outcomes after surgery are usually worse than those without dementia. Widespread adoption of electronic health records (EHRs) may allow hospitals to better monitor long-term health outcomes in patients with dementia after hospitalization. This study aimed to (1) estimate how dementia influences discharge location, mortality, and readmission 180 days and 1 year after hip fracture surgery in older adults, and (2) demonstrate the feasibility of using selection-bias reduced EHR data for research and long-term health outcomes monitoring.

DESIGN

Retrospective observational cohort study using EHRs.

SETTING AND PARTICIPANTS

A cohort of 1171 patients over age 65 years who had an initial hip fracture surgery between October 2015 and December 2018 was extracted from EHRs of one health system; 376 of these patients had dementia.

METHODS

Logistic regression was applied to estimate influences of dementia on discharge disposition and Cox proportional hazards model for mortality. The Fine and Gray regression model was used to analyze readmission, accounting for the competing risk of death. To reduce selection bias in EHRs, inverse probability of treatment weighting using propensity scores was implemented before modeling.

RESULTS

Dementia had significant impacts on all outcomes: being discharged to facilities [odds ratio (OR) = 2.11, 95% confidence interval (CI) 1.19-3.74], 180-day mortality [hazard ratio (HR) = 1.69, 95% CI 1.20-2.38], 1-year mortality (HR = 1.78, 95% CI 1.33-2.38), 180-day readmission (HR = 1.62, 95% CI 1.39-1.89), and 1 year readmission (HR = 1.39, 95% CI 1.21-1.58).

CONCLUSIONS AND IMPLICATIONS

Dementia was a significant risk factor for worse long-term outcomes. The inverse probability of treatment weighting approach can be used to reduce selection bias in EHR data for research and monitoring long-term health outcomes in the target population. Such monitoring could foster collaborations with post-acute and long-term health care services to improve recovery outcomes in patients with dementia after hip fracture surgery.

Nationwide Database Analysis of Risk Factors Associated with Decreased Activities of Daily Living in Patients with Alzheimer's Disease

BACKGROUND

Preserving activities of daily living (ADL) is the key issue for Alzheimer's disease (AD) patients and their caregivers.

OBJECTIVE

To clarify the ADL level of AD patients at diagnosis and the risk factors associated with decreased ADL during long-term care (≤3 years).

METHODS

Medical records of AD patients in a Japanese health insurance claims database were analyzed retrospectively to determine ADL using the Barthel Index (BI) and identify the risk factors associated with decreased ADL.

RESULTS

A total of 16,799 AD patients (mean age at diagnosis: 83.6 years, 61.5% female) were analyzed. Female patients were older (84.6 versus 81.9 years; p < 0.001) and had lower BI (46.8 versus 57.6; p < 0.001) and body mass index (BMI) (21.0 versus 21.7 kg/m2; p < 0.001) than male patients at diagnosis. Disability (BI≤60) increased at age≥80 years and was significantly higher in females. Complete disability was most frequent for bathing and grooming. Risk factors for decreased ADL were determined separately by sex through comparing the ADL-preserved and ADL-decreased groups using propensity score matching by age and BI and multivariable logistic regression analysis. In males, decreased ADL was significantly associated with BMI < 21.5 kg/m2, stroke, and hip fracture, and inversely associated with hyperlipidemia. In females, decreased ADL was significantly associated with BMI < 21.5 kg/m2 and vertebral and hip fractures, and inversely associated with lower back pain.

CONCLUSION

AD patients with low BMI, stroke, and fractures had increased risks of decreased ADL; such patients should be identified early and managed appropriately, including rehabilitation to preserve ADL.

Effects of Hochuekkito on Physical Activity and Appetite in Postoperative Elderly Patients with Hip Fractures: A Randomized Controlled Trial

Objectives

Hip fracture in the elderly involves two cases of invasive damage to the body within a short period of time: the fracture itself and subsequent surgery. This situation affects physical strength and presents a major challenge during convalescent rehabilitation. This study aimed to evaluate the effects of hochuekkito, a traditional Japanese herbal medicine, on physical activity, appetite, motivation, and quality of life (QOL) during inpatient rehabilitation treatment after hip surgery.

Methods

Thirty-eight patients with hip fracture who underwent postoperative convalescent rehabilitation were randomly assigned to either the hochuekkito group (n=20, daily hochuekkito administration from day 3 after surgery until discharge from hospital) or the control group (n=18). Physical activity was measured with a small tri-axial accelerometer worn by the patients; appetite was evaluated based on daily dietary calorie consumption; motivation was measured using the vitality index score; and QOL was measured using the European QOL 5-Dimensions 5-Levels questionnaire and its associated EQ-visual analog scale (EQ-VAS). All patients were assessed at day 3 (baseline) and 2, 4, 6, 8, and 10 weeks after surgery and at the time of discharge from hospital.

Results

The results for the hochuekkito group were significantly higher than the control group for walking exercise at 10 weeks, vigorous activity time at 8 weeks, dietary calorie consumption at 10 weeks and at discharge, and EQ-VAS score at 6 weeks.

Conclusions

In elderly hip fracture patients, a course of hochuekkito administration starting soon after surgery significantly improved QOL, physical activity, and appetite at 6 weeks after surgery.

Hip Fracture as a Predictive Marker for the Risk of Dementia: A Population-Based Cohort Study

OBJECTIVES

This study aimed to investigate the association between hip fracture and the risk of dementia.

DESIGN

A retrospective real-world propensity score-matched cohort study was conducted using the real-world hip fracture cohort (RHFC).

SETTING AND PARTICIPANTS

Electronic health record data from the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong were used. A total of 52,848 patients aged ≥65 years and with at least an event of fall from 2006 to 2015 were included in the RHFC.

METHODS

The incidence of fall, hip fracture, and dementia was determined using their International Classification of Diseases, Ninth Revision (ICD-9) codes. Competing risk regression models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

Hip fracture was associated with an increased risk of dementia (HR 1.09, 95% CI 1.04-1.15, P < .001). The subgroup analysis showed that association was significant in women but not in men.

CONCLUSIONS AND IMPLICATIONS

Hip fracture was associated with the increased risk of dementia among older adults. Further studies investigating the potential roles of hip fracture in the development of dementia could benefit the management of both conditions in older adults.

Differential Impact of Cigarette Smoking on Fracture Risks in Subjective Cognitive Decline and Dementia: A Nationwide Longitudinal Study

OBJECTIVE

We aimed to explore the differential impact of cigarette smoking on fracture risks in SCD and dementia.

METHODS

A nationwide population-based cohort study design was used. Out of all the people aged 66 (n=1,555,103) who went through the National Screening Program from 2009-2014, 968,240 participants with eligible data were included in the study. Time-to-event was calculated as the duration between the NSPTA and fracture incidence. Cox proportional-hazard regression analyses were conducted to evaluate the risk of fractures.

RESULTS

Increased risk of all [adjusted hazard ratio (aHR)=1.184; 95% confidence interval (CI)=1.184, 1.093-1.283], hip (aHR=1.518; 95% CI=1.168-4.972), vertebral (aHR=1.235; 95% CI=1.101-1.386) fractures were increased in current smokers with more than 20 or more pack years (≥20 py) of SCD group, after adjusting for all relevant confounding factors. In dementia group, however, current smokers ≥20 py were at reduced risk of hip fractures (aHR=0.249; 95% CI=0.089-0.97).

CONCLUSION

There was a disparate influence of cigarette smoking on the fracture risks in SCD and dementia group. Further studies are warranted to explicate this phenomenon, and personalized preventive measures according to one's cognitive status are imperative, since risk factors of fractures can exert disparate influence on patients at different stage of cognitive trajectory.

Role of low dose 256-slice CT perfusion imaging in predicting mediastinal lymph node metastasis of lung cancer

SUMMARY OBJECTIVE: CT perfusion (CTP) is an imaging technique that can be used to evaluate the changes in the microcirculation of tumor tissues. Our study aimed to investigate the role of CTP in predicting mediastinal lymph node metastasis. METHODS: Clinical data of 58 patients who received surgical resection of lung cancer and lymph node dissection in our hospital from June 2012 to December 2014 were collected. Patients were divided into a positive lymph node metastasis group and a negative lymph node metastasis group. Parameters of CTP, including peak enhancement intensity (PEI), perfusion value (PV), as well as blood volume (BV), were compared between the two groups. The receiver-operating characteristic (ROC) curve was used to predict mediastinal lymph node metastasis. RESULTS: The PV of the positive lymph node metastasis group was significantly higher than that of the negative group (p < 0.001). The ROC curve analysis showed that PV can be used as an index to predict mediastinal lymph node metastasis of lung cancer. The sensitivity and specificity of a PV greater than 7.5ml·min-1·ml-1 in predicting lymph node metastasis of lung cancer were 78.3 % and 91.4 %, respectively. CONCLUSION: The PV of low dose CT perfusion can be used as an index for predicting mediastinal lymph node metastasis of lung cancer.

The risk of fall accidents for home dwellers with dementia-A register- and population-based case-control study

Introduction

Institutionalized people with dementia have an increased risk of fall accidents, but little is known about whether this increased risk holds for home dwellers.

Methods

This register- and population-based study comprised 115,584 cases and 394,679 controls. Cases were individuals with any fall between 2009 and 2014, and matched with up to six controls on age, sex, and geographic location. Individuals were excluded if they (1) had any fall in 2008, or (2) lived in a nursing home on the date of the fall. Dementia, other chronic diseases, and sedative medicines were assessed from Danish national registers.

Results

After adjusting for potential confounders, older people with dementia living at home had a 1.89-fold higher risk of fall (odds ratio = 1.89, 95% confidence interval [1.84–1.94], P < .001).

Discussion

Dementia almost doubles the risk of fall for older Danish people living at home. This highlights the need for effective fall preventions that target people with dementia.

Comparison of predictors of hip fracture and mortality after hip fracture in community-dwellers with and without Alzheimer's disease - exposure-matched cohort study

BACKGROUND

Dementia, with Alzheimer's disease (AD) being the most common form, is a major hip fracture risk factor, but currently it is not known whether the same factors predict hip fracture among persons with and without dementia/AD. We compared the predictors of hip fracture and mortality after hip fracture in persons with and without AD.

METHODS

An exposure-matched cohort of all community-dwellers of Finland who received a new clinically verified AD diagnosis in 2005-2011 and had no history of previous hip fracture (N = 67,072) and an age, sex, and region-matched cohort of persons without AD (N = 67,072). Associations between sociodemographic characteristics, comorbidities and medications and risk of hip fracture and mortality after hip fracture were assessed with Cox regression.

RESULTS

As expected, the incidence of hip fractures in 2005-2012 (2.19/100 person-years vs 0.90/100 person-years in the non-AD cohort), as well as mortality after hip fracture (29/100 person-years vs 23/100 person-years in the non-AD cohort) were higher in the AD cohort. This difference was evident regardless of the risk factors. Mental and behavioural disorders (adjusted hazard ratio; HR 95% confidence interval CI: 1.16, 1.09-1.24 and 1.71, 1.52-1.92 in the AD and non-AD-cohorts), antipsychotics (1.12, 1.04-1.20 and 1.56, 1.38-1.76 for AD and non-AD-cohorts) and antidepressants (1.06, 1.00-1.12 and 1.34 1.22-1.47 for AD and non-AD-cohorts) were related to higher, and estrogen/combination hormone therapy (0.87, 0.77-0.9 and 0.79, 0.64-0.98 for AD and non-AD-cohorts) to lower hip fracture risk in both cohorts. Stroke (1.42, 1.26-1.62), diabetes (1.13, 0.99-1.28), active cancer treatment (1.67, 1.22-2.30), proton pump inhibitors (1.14, 1.05-1.25), antiepileptics (1.27, 1.11-1.46) and opioids (1.10, 1.01-1.19) were associated with higher hip fracture risk in the non-AD cohort. Similarly, the associations between mortality risk factors (age, sex, several comorbidities and medications) were stronger in the non-AD cohort.

CONCLUSIONS

AD itself appears to be such a significant risk factor for hip fracture, and mortality after hip fracture, that it overrules or diminishes the effect of other risk factors. Thus, it is important to develop and implement preventive interventions that are suitable and effective in this population.