Bone mineral density, adiposity, and cognitive functions

Impact of dementia and mild cognitive impairment on bone health in older people

Mild cognitive impairment, dementia and osteoporosis are common diseases of ageing and, with the increasingly ageing global population, are increasing in prevalence. These conditions are closely associated, with shared risk factors, common underlying biological mechanisms and potential direct causal pathways. In this review, the epidemiological and mechanistic links between mild cognitive impairment, dementia and skeletal health are explored. Discussion will focus on how changes in brain and bone signalling can underly associations between these conditions, and will consider the molecular and cellular drivers in the context of inflammation and the gut microbiome. There is a complex interplay between nutritional changes, which may precede or follow the onset of mild cognitive impairment (MCI) or dementia, and bone health. Polypharmacy is common in patients with MCI or dementia, and there are difficult prescribing decisions to be made due to the elevated risk of falls associated with many drugs used for associated problems, which can consequently increase fracture risk. Some medications prescribed for cognitive impairment may directly impact bone health. In addition, patients may have difficulty remembering medication without assistance, meaning that osteoporosis drugs may be prescribed but not taken. Cognitive impairment may be improved or delayed by physical activity and exercise, and there is evidence for the additional benefits of physical activity on falls and fractures. Research gaps and priorities with the aim of reducing the burden of osteoporosis and fractures in people with MCI or dementia will also be discussed.

Cognitive impairment and risks of osteoporosis: A systematic review and meta-analysis

OBJECTIVE

To systematically assess the association between osteoporosis and cognitive impairment, and to provide new light on the prevention of cognitive impairment in patients with osteoporosis.

METHOD

A comprehensive research of Embase, Cochrane Library, PubMed, Web of Science, CNKI, Wangfang Data and VIP was performed from inception to January 2022, using the search term 'osteoporosis' and 'cognitive impairment'. Literature screening, data extraction and quality evaluation were conducted by two reviewers independently, and meta-analysis was performed by RevMan 5.4 software.

RESULTS

A total of 8 studies (136222 participants) were included. Meta-analysis showed that patients with osteoporosis had an increased risk of cognitive impairment [OR=2.01, 95% CI(1.63-2.48), P<0.01]. This initial meta-analysis had significant heterogeneity, and subgroup analysis suggested that potential heterogeneity in different study types, age and outcome indicators.

CONCLUSION

Patients with osteoporosis are at increased risk of cognitive impairment, and osteoporosis intervention could prevent or delay the onset of cognitive impairment for those at risk.

Osteoporosis is associated with elevated baseline cerebrospinal fluid biomarkers and accelerated brain structural atrophy among older people

Objective

The aim of this study was to examine whether osteoporosis (OP) is associated with Alzheimer’s disease-related cerebrospinal fluid (CSF) biomarkers and brain structures among older people.

Methods

From the Alzheimer’s disease Neuroimaging Initiative database, we grouped participants according to the OP status (OP+/OP−) and compared the Alzheimer’s disease (AD)-related CSF biomarker levels and the regional brain structural volumes between the two groups using multivariable models. These models were adjusted for covariates including age, education, gender, diagnosis of Alzheimer’s disease, and apolipoprotein E4 carrier status.

Results

In the cross-sectional analyses at baseline, OP was related to higher CSF t-tau (total tau) and p-tau₁₈₁ (tau phosphorylated at threonine-181) but not to CSF amyloid-beta (1–42) or the volumes of entorhinal cortex and hippocampus. In the longitudinal analyses, OP was not associated with the change in the three CSF biomarkers over time but was linked to a faster decline in the size of the entorhinal cortex and hippocampus.

Conclusion

OP was associated with elevated levels of CSF t-tau and p-tau₁₈₁ at baseline, and accelerated entorhinal cortex and hippocampal atrophies over time among older people.

Intake of Docosahexaenoic Acid-Enriched Milk Beverage Prevents Age-Related Cognitive Decline and Decreases Serum Bone Resorption Marker Levels

The pathogenic mechanism of dementia is still unknown, and the fundamental treatment remains to be established. Thus, there is growing interest in preventing dementia through diet. One of the functional ingredients attracting attention is docosahexaenoic acid. We conducted a 12-month, randomized, double-blind, placebo-controlled clinical trial in healthy elderly Japanese individuals with a Mini-Mental State Examination score of 28 or higher at baseline using a docosahexaenoic acid-enriched milk beverage containing 297 mg docosahexaenoic acid and 137 mg eicosapentaenoic acid. Consumption of a docosahexaenoic acid-enriched milk beverage increased the fatty acid levels of docosahexaenoic acid and eicosapentaenoic acid in erythrocyte membranes, which was the primary outcome of this study. Moreover, intake of this beverage prevented age-related cognitive decline and decreased serum bone resorption marker levels. Our data demonstrate that, even at a low dose, long-term daily intake of docosahexaenoic acid prevents dementia and may show beneficial effect on bone health.

Bone Mineral Density Measurements and Association With Brain Structure and Cognitive Function: The Framingham Offspring Cohort

BACKGROUND

Bone mineral density (BMD) is a potential surrogate marker of lifetime estrogen exposure previously linked to increased risk of Alzheimer dementia among elderly women. We examine the association between BMD in the "young old" with imaging biomarkers of brain aging and cognitive performance.

METHODS

Offspring participants (N=1905, mean age 66) of a population-based cohort who had BMD, brain imaging and detailed cognitive assessment were included in the study. Sex-stratified, linear, and logistic regression models were used for analysis.

RESULTS

Higher femoral neck BMD was associated with lower white matter hyperintensity burden and better performance on Trails B-A in both sexes, even after adjustment for cerebrovascular risk factors. Among women, the positive association with Trails B-A performance was seen only in APOE4 allele carriers. Higher BMD measurements were linked to better visual reproductions test performance in men. Finally, among women, higher femoral trochanter BMD was associated with better logical memory and Hooper visual organization test performance.

CONCLUSION

Among the "young old," higher BMD is associated with less white matter hyperintensity burden and better, domain-specific, cognitive performance. This suggests that lifetime estrogen exposure may modulate the degree of cumulative vascular brain injury independent of cerebrovascular risk factors.

Association between osteosarcopenia and cognitive frailty in older outpatients visiting a frailty clinic

PURPOSE

Osteosarcopenia and cognitive frailty are both risk factors for falls and fractures. The purpose of this study was to determine the association between osteosarcopenia and cognitive frailty.

MATERIALS AND METHODS

This was a cross-sectional secondary data analysis of the Frailty Registry Study with outpatients aged ≥65 years who visited a frailty clinic at a geriatric hospital. Osteoporosis was defined as a bone mineral density < 70% of the young adult mean. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia 2019 criteria. Cognitive frailty was defined as the coexistence of physical frailty and mild cognitive impairment. Physical frailty was evaluated according to Japanese Cardiovascular Health Study criteria, whereas mild cognitive impairment was defined as a Mini-Mental State Examination score ≥ 24 points and a score ≤ 25 points on the Japanese version of the Montreal Cognitive Assessment. We performed multivariable logistic regression analysis to investigate the association between osteosarcopenia and cognitive frailty.

RESULTS

The data of 432 patients were analysed. The prevalence of osteosarcopenia and cognitive frailty was 10.2% and 20.8%, respectively. Logistic regression analysis revealed that osteosarcopenia was independently associated with cognitive frailty with a higher odds ratio than osteoporosis or sarcopenia alone. Lost points in visuospatial abilities/executive functions and orientation were significantly associated with osteosarcopenia.

CONCLUSIONS

Combination of osteoporosis and sarcopenia is more likely to be associated with physical and cognitive decline than osteoporosis and sarcopenia alone. The mechanism by which osteosarcopenia is associated with decreased visuospatial abilities/executive functions and orientation needs to be addressed.

Effect of Memantine Treatment and Combination with Vitamin D Supplementation on Body Composition in the APP/PS1 Mouse Model of Alzheimer's Disease Following Chronic Vitamin D Deficiency

BACKGROUND

Vitamin D deficiency and altered body composition are common in Alzheimer's disease (AD). Memantine with vitamin D supplementation can protect cortical axons against amyloid-β exposure and glutamate toxicity.

OBJECTIVE

To study the effects of vitamin D deprivation and subsequent treatment with memantine and vitamin D enrichment on whole-body composition using a mouse model of AD.

METHODS

Male APPswe/PS1dE9 mice were divided into four groups at 2.5 months of age: the control group (n = 14) was fed a standard diet throughout; the remaining mice were started on a vitamin D-deficient diet at month 6. The vitamin D-deficient group (n = 14) remained on the vitamin D-deficient diet for the rest of the study. Of the remaining two groups, one had memantine (n = 14), while the other had both memantine and 10 IU/g vitamin D (n = 14), added to their diet at month 9. Serum 25(OH)D levels measured at months 6, 9, 12, and 15 confirmed vitamin D levels were lower in mice on vitamin D-deficient diets and higher in the vitamin D-supplemented mice. Micro-computed tomography was performed at month 15 to determine whole-body composition.

RESULTS

In mice deprived of vitamin D, memantine increased bone mineral content (8.7% increase, p < 0.01) and absolute skeletal tissue mass (9.3% increase, p < 0.05) and volume (9.2% increase, p < 0.05) relative to controls. This was not observed when memantine treatment was combined with vitamin D enrichment.

CONCLUSION

Combination treatment of vitamin D and memantine had no negative effects on body composition. Future studies should clarify whether vitamin D status impacts the effects of memantine treatment on bone physiology in people with AD.

Eating Behavior in Aging and Dementia: The Need for a Comprehensive Assessment

Eating behavior can change during aging due to physiological, psychological, and social changes. Modifications can occur at different levels: (1) in food choice, (2) in eating habits, and (3) in dietary intake. A good dietary behavior, like the Mediterranean dietary pattern, can be a protective factor for some aging related pathologies, such as dementia, while a worse eating behavior can lead to pathological conditions such as malnutrition. Changes in eating behavior can also be linked to the onset of dementia: for some types of dementia, such as frontotemporal dementia, dietary changes are one of the key clinical diagnostic feature, for others, like Alzheimer's disease, weight loss is a clinical reported feature. For these reasons, it is important to be able to assess eating behavior in a proper way, considering that there are normal age-related changes. An adequate assessment of dietary behavior can help to plan preventive intervention strategies for heathy aging or can help to identify abnormal behaviors that underline aging related-diseases. In this review, we have analyzed normal age-related and dementia-related changes and the tools that can be used to assess eating behavior. Thus, we make recommendations to screening and monitoring eating behavior in aging and dementia, and to adopt these tools in clinical practice.

Effects of Neurological Disorders on Bone Health

Neurological diseases, particularly in the context of aging, have serious impacts on quality of life and can negatively affect bone health. The brain-bone axis is critically important for skeletal metabolism, sensory innervation, and endocrine cross-talk between these organs. This review discusses current evidence for the cellular and molecular mechanisms by which various neurological disease categories, including autoimmune, developmental, dementia-related, movement, neuromuscular, stroke, trauma, and psychological, impart changes in bone homeostasis and mass, as well as fracture risk. Likewise, how bone may affect neurological function is discussed. Gaining a better understanding of brain-bone interactions, particularly in patients with underlying neurological disorders, may lead to development of novel therapies and discovery of shared risk factors, as well as highlight the need for broad, whole-health clinical approaches toward treatment.

Executive functions predict fracture risk in postmenopausal women assessed for osteoporosis

BACKGROUND

Cognitive impairment and muscle strength have been associated with bone fragility. However, the potential predictive role of executive functions on fracture risk has been poorly investigated.

AIM

We intended to explore the association between executive functions, psychological distress and physical performance with fracture risk in postmenopausal women.

METHODS

Cognitive tests explicating executive functions (i.e., Trial Making Test-B, Digit Span Backward, Digit Span Forward) and questionnaires assessing psychological distress (i.e., Back Depression Inventory and Hamilton Anxiety Scale) were administered. Physical performance was explored through the Short Physical Performance Battery and handgrip strength. The 10-year probability of major and hip fractures was assessed by Fracture Risk Assessment tool (FRAX); the bone mineral density (BMD) was evaluated by Dual-Energy X-ray Absorptiometry.

RESULTS

60 women (mean age 66 ± 7.99 yr.) were recruited. The FRAX score for major fractures was significantly associated with Trial Making Test B score (r = - 0.25) and with Digit Span Backward (r = - 0.34); the FRAX score for hip fracture was associated with handgrip strength (r = - 0.39, p = 0.002). BMD was significantly associated with Digit Span Backward (r = - 0.32) and with depression (r = - 0.33). After several adjustments, the multiple regression analysis showed that BMI (ß = 0.09, SE 0.03, p = 0.013), Beck Depression Inventory score (ß = - 0.09, SE 0.06, p = 0.04) and Digit Span Backward score (ß = 0.55, SE 0.17, p = 0.002) were independently predictive of lumbar BMD.

CONCLUSIONS

Verbal working memory, as assessed by Digit Span Test, and psychological features were associated with BMD and could contribute to fracture risk prediction in postmenopausal women.

Osteoporosis and cognitive impairment interwoven warning signs: community-based study on older adults-Bushehr Elderly Health (BEH) Program

Cognitive impairment and osteoporosis are frequently seen to coincide in clinical practice. Osteoporosis was higher in elderly populations with cognitive impairment, especially in postmenopausal women. Thus, prophylaxis for osteoporosis, falls, and fractures should be considered as part of the treatment of patients with cognitive impairment.

INTRODUCTION

Cognitive impairment and osteoporosis are two important health concerns among older adults that their possible relationship, concurrent occurrence, and linking mechanism have recently been highlighted. The purpose of this study was to assess the sex-independent association of these two conditions.

MATERIALS AND METHODS

From among 2331 individuals aged ≥ 60 years selected in Bushehr Elderly Health (BEH) Program, Iran; data of 1508 participants were analyzed. Cognitive status was assessed using Category Fluency Test and Mini-cog assessment instrument. Association between osteopenia-osteoporosis and cognitive impairment were assessed using uni- and multivariable logistic regression models.

RESULTS

Osteoporosis was diagnosed in 598 (39.6%) of the participants (58.3% female and 21.9% male, P < 0.001). From among them, 677 (44.9%) had evidence of cognitive impairment (64.5% female and 31.0% male, P < 0.001). Multivariate logistic regressions showed spinal and total hip osteoporosis was associated with 1.83 (CI 95% 1.13-2.96) and 2.24-fold (CI 95% 1.28-3.89) increase in the risk of cognitive impairment among female subjects, respectively. Ordinal logistic regression, on the other hand, revealed cognitive impairment to be associated with 1.42-fold (CI 95% 1.04-1.92) increase in the risk of spinal osteopenia-osteoporosis, 1.5-fold increase in total hip osteoporosis (CI 95% 1.09-2.05), and 1.48-fold increase in general osteoporosis (CI 95% 1.06-2.0).

CONCLUSION

Different degrees of bone loss and cognitive impairment may be a risk factor for each other among women but not in men. It is suggested that the screening, adopting preventive measures for the other condition and regular follow-ups, if needed, could be of utmost importance.

Are Bisphosphonates Associated with Adverse Metabolic and Cognitive Effects? A Study in Intact Rats and Rats Fed High-Fat High-Fructose Diet

Osteocalcin, known as a bone gla protein, is considered a regulator of energy metabolism and behavior in its undercarboxylated form (ucOC). Antiresorptive drugs, such as alendronate, reduce serum level of ucOC. The purpose of the current study was to verify if alendronate might impact on energy metabolism and animal behavior by reducing ucOC level and to find out if the presence of metabolic alterations would further worsen these potential adverse effects. Four groups of male Wistar rats (12 per group) were used: a control group, a group receiving high-fat high-fructose diet (HFHF), a group treated with alendronate, and a group receiving alendronate and HFHF. Alendronate was administered subcutaneously in a dose of 50 mcg/kg thrice weekly. Study duration was 15 weeks. Animals were tested for locomotion, anxiety and spatial memory. Glucose and insulin tolerance tests evaluated the glucose metabolism. Visceral obesity was assessed by the weight of right retroperitoneal fat pads. Concentration of ucOC was measured in the serum. Alendronate reduced serum ucOC concentration, increased fasting blood glucose level, and worsened insulin sensitivity. It did not increase visceral adiposity. Fat index was negatively correlated with ucOC in all animals and in the alendronate-treated rats. Alendronate worsened spatial memory of the animals and ucOC levels correlated positively with their cognitive performance.

Interaction of bone and brain: osteocalcin and cognition

INTRODUCTION

Bone has conventionally been considered to be a passive organ that only receives external control, but according to recent findings, it has become clear that bone is an endocrine organ that actively regulates systemic metabolism through osteocalcin (OC).

METHODS

We focus on the relationship between the brain and bone and summarize the effects of OC on cognitive function as well as the association between OC and improved cognitive function through exercise.

RESULTS

The findings suggest that the decrease in OC produced by bone is responsible for the decrease in cognitive function associated with aging. Furthermore, positive effect of improving cognitive function can generally be recognized in exercise interventions conducted for healthy elderly people and those with MCI, and moderate exercise is particularly effective for dementia prevention.

CONCLUSION

The improving bone health with aging may exert beneficial effects on cognition.

Mechanistic complexities of bone loss in Alzheimer's disease: a review

Purpose/Aim: Alzheimer's disease (AD), the primary cause of dementia in the elderly, is one of the leading age-related neurodegenerative diseases worldwide. While AD is notorious for destroying memory and cognition, dementia patients also experience greater incidence of bone loss and skeletal fracture than age-matched neurotypical individuals, greatly impacting their quality of life. Despite the significance of this comorbidity, there is no solid understanding of the mechanisms driving early bone loss in AD. Here, we review studies that have evaluated many of the obvious risk factors shared by dementia and osteoporosis, and illuminate emerging work investigating covert pathophysiological mechanisms shared between the disorders that may have potential as new risk biomarkers or therapeutic targets in AD.Conclusions: Skeletal deficits emerge very early in clinical Alzheimer's progression, and cannot be explained by coincident factors such as aging, female sex, mobility status, falls, or genetics. While research in this area is still in its infancy, studies implicate several potential mechanisms in disrupting skeletal homeostasis that include direct effects of amyloid-beta pathology on bone cells, neurofibrillary tau-induced damage to neural centers regulating skeletal remodeling, and/or systemic Wnt/Beta-catenin signaling deficits. Data from an increasing number of studies substantiate a role for the newly discovered "exercise hormone" irisin and its protein precursor FNDC5 in bone loss and AD-associated neurodegeneration. We conclude that the current status of research on bone loss in AD is insufficient and merits critical attention because this work could uncover novel diagnostic and therapeutic opportunities desperately needed to address AD.

Aging-related changes in fluid intelligence, muscle and adipose mass, and sex-specific immunologic mediation: A longitudinal UK Biobank study

BACKGROUND

Obesity in midlife and early late-life is associated with worse normal cognitive aging. Dual-energy X-ray absorptiometry (DEXA) suggests that visceral adipose mass (VAM) plays a predominant role, whereas non-visceral adipose mass (NVAM) and lean muscle mass (LMM) have shown conflicting relationships. It is unknown how longitudinal, cognitive changes in age-sensitive domains like fluid intelligence (FI) correspond to VAM, NVAM, and LMM in women and men. Furthermore, changes over time in blood leukocyte sub-populations may partially or fully account for sex-specific associations.

METHODS

Data on 4431 late middle-aged, cognitively unimpaired adults (mean = 64.5 y) was obtained from the UK Biobank prospective cohort across 22 centers. FI scores, blood leukocyte counts, and covariates (age, social class, education) were measured at three 2-year intervals over 6 years. DEXA collection overlapped with these intervals. Sex-stratified growth curves, structural equations, and Preacher-Hayes mediation were used to estimate direct and indirect effects. β-weights were standardized.

RESULTS

More LMM predicted gains in FI scores among women (β = 0.130, p < .001) and men (β = 0.089, p < .001). Conversely, more VAM and NVAM independently predicted FI decline equally among sexes (e.g., NVAM: women: β = -0.082, p < .001; men: β = -0.076, p < .001). Among women, FI associations were fully mediated by higher eosinophil counts via VAM (λ = 30.8%, p = .028) and lower lymphocyte counts via LMM (λ = 69.2%, p = .021). Among men, FI associations were partially mediated by lower basophils counts via LMM (λ = 4.5%, p = .042) and higher counts via VAM (λ = 50%, p = .037).

CONCLUSION

The proportion of LMM and VAM equally influenced male FI changes over 6 years, whereas higher LMM among women appeared to more strongly influence. FI changes. Leukocyte counts strongly mediated VAM- and LMM-related FI changes in a sex-specific manner, but not for NVAM. For clinical translation, exercise studies in older adults may benefit from assessing sex-specific values of DEXA-based tissue mass, FI, and leukocyte sub-populations to gauge potential cognitive benefits of less VAM and more LMM.

The Endocrine Function of Osteocalcin Regulated by Bone Resorption: A Lesson from Reduced and Increased Bone Mass Diseases

Bone is a peculiar tissue subjected to a continuous process of self-renewal essential to assure the integrity of the skeleton and to explicate the endocrine functions. The study of bone diseases characterized by increased or reduced bone mass due to osteoclast alterations has been essential to understand the great role played by osteocalcin in the endocrine functions of the skeleton. The ability of osteoclasts to regulate the decarboxylation of osteocalcin and to control glucose metabolism, male fertility, and cognitive functions was demonstrated by the use of animal models. In this review we described how diseases characterized by defective and increased bone resorption activity, as osteopetrosis and osteoporosis, were essential to understand the involvement of bone tissue in whole body physiology. To translate this knowledge into humans, recently published reports on patients were described, but further studies should be performed to confirm this complex hormonal regulation in humans.

Measurement matters: higher waist-to-hip ratio but not body mass index is associated with deficits in executive functions and episodic memory

Background

The current study aimed to reconcile the inconsistent findings between obesity, executive functions, and episodic memory by addressing major limitations of previous studies, including overreliance on body mass index (BMI), small sample sizes, and failure to control for confounds.

Methods

Participants consisted of 3,712 midlife adults from the Cognitive Project of the National Survey of Midlife Development. Executive functions and episodic memory were measured by a battery of cognitive function tests.

Results

We found that higher waist-to-hip ratio was associated with deficits in both executive functions and episodic memory, above and beyond the influence of demographics, comorbid health issues, health behaviors, personality traits, and self-perceived obesity. However, higher BMI was not associated with deficits in executive functions and episodic memory. More importantly, these differential associations were robust and stable across adulthood.

Discussion

Our findings confirm the association between obesity and episodic memory while highlighting the need for better measures of obesity when examining its associations with individual differences in cognitive functions.

Associations of Childhood and Adulthood Cognition with Bone Mineral Density in Later Adulthood: A Population-Based Longitudinal Study

This study explores the association between cognitive ability in childhood and midlife and bone health outcomes in early old age; and the relationships of these bone measures with contemporaneous and subsequent cognitive ability in the MRC National Survey of Health and Development (NSHD). This British birth cohort assessed areal and volumetric bone mineral density (aBMD and vBMD) at age 60-64, derived from peripheral quantitative computed tomography and dual-energy X-ray absorptiometry, and cognitive performance from childhood to age 69, among 866 women and 792 men. Cognitive performance at age 15 was assessed using tests of verbal and non-verbal ability, and mathematics; and memory and search speed tasks were administered at ages 53, 60-64, and 69. Covariates included body size, pubertal timing, smoking, leisure time physical activity, socioeconomic circumstances and menopause timing. Multiple linear regression analyses showed that higher childhood cognitive ability was associated with higher hip aBMD, in women, and greater cortical and trabecular vBMD, in men. For women, there were positive associations between hip aBMD and total vBMD, and contemporaneous cognitive ability with associations also extending to subsequent cognitive ability for total vBMD. For men, some associations with trabecular and total vBMD emerged at ages 60-64 and 69 but only after adjusting for education, occupational class and health behaviors. Our findings highlight that higher cognitive ability in childhood is associated with BMD in early old age and these associations might be explained by social and behavioral pathways. The results suggest that individuals with greater cognitive ability in early life are more likely to engage in healthy behaviors (e.g., leisure time physical activity) in adulthood, which in turn are associated with greater BMD later in life. Associations between bone health and cognitive performance should be considered within a life course framework; and the potential role of smoking and physical activity should be addressed when advising adults at high future risk of osteoporosis and fracture.

Association between osteocalcin and cognitive performance in healthy older adults

Introduction

cognitive deterioration and reductions of bone health coincide with increasing age. We examine the relationship between bone composition and plasma markers of bone remodelling with measures of cognitive performance in healthy adults.

Methods

this cross-sectional study included 225 old (52% women, mean age: 74.4 ± 3.3 years) and 134 young (52% women, mean age: 23.4 ± 2.7 years) adult participants from the MyoAge project. Whole body bone mineral density was measured by dual-energy X-ray absorptiometry. Blood analyses included a panel of bone-related peptides (dickkopf-1, osteoprotegerin, osteocalcin (OC), osteopontin, sclerostin, parathyroid hormone and fibroblast growth factor 23), as well as serum calcium and 25-hydroxy vitamin D assays. A selection of cognitive domains (working memory capacity, episodic memory, executive functioning and global cognition) was assessed with a standardised neuropsychological test battery.

Results

adjusting for covariates and multiple testing revealed that plasma OC levels were positively associated with measures of executive functioning (β = 0.444, P < 0.001) and global cognition (β = 0.381, P = 0.001) in the older women.

Discussion

these correlative results demonstrate a positive association between OC, a factor known to regulate bone remodelling, with cognitive performance in older non-demented women. Further work should address possible mechanistic interpretations in humans.