Serum lipid traits and the risk of dementia: A cohort study of 254,575 women and 214,891 men in the UK Biobank

Uncertainty in the estimated effects of statin initiation on risk of dementia: using a multiverse analysis to assess sources of variability

Mixed evidence on how statins affect dementia risk may reflect variability in model specifications. Alternate specifications are rarely systematically compared. Using an emulated trial design framework, we investigated variation in the estimated effect of statin initiation on dementia across alternative (1) eligibility criteria, (2) confounding variable sets, and (3) outcome definitions. Kaiser Permanente Northern California members' linked electronic health records from 1996 to 2020 were used to identify statin initiation and dementia diagnoses. Statin initiators were matched on age and low-density lipoprotein cholesterol with up to 5 non-initiators. Possible covariates included clinical (n = 1.4 million); socioeconomic and behavioral (n = 265,224); and genetic (n = 69,573) variables. Using Cox proportional-hazards models, we estimated variation across 1.27 million intent-to-treat estimates for statin initiation varying specification of eligibility, outcome definition, and covariates. Estimated hazard ratios (HRs) for statin initiation on dementia across all specifications ranged from 0.93 to 1.47. The variance of estimates due to model specification differences was 7.6 times larger than the average variance of specific estimates due to finite sample size. Three modeling decisions notably attenuated coefficients [ln(HR)]: requiring a run-in period prior to the emulated trial start date (0.034); adjustment for diabetes (0.030) and cardiovascular disease (0.039); and excluding the first year of follow-up (0.041). HRs from models with all three specifications ranged from 0.99 to 1.15. No specification we evaluated consistently generated protective effects. Estimates of the association between statin initiation and dementia leveraging real world data are sensitive to model specification, especially decisions related to clinical covariates and time-at-risk.

The interaction between circadian syndrome and genetic susceptibility in the risk of incident dementia: A longitudinal cohort study

BACKGROUND

Despite growing interest in circadian disturbances as potential triggers for dementia, the specific impact of circadian syndrome (CircS) on dementia incidence remains poorly understood. Moreover, the role of genetic susceptibility modulating these effects remains to be explored.

METHODS

Dementia-free participants from the UK Biobank cohort were included in the analysis. To evaluate the association between CircS and the incidence of dementia, as well as the modifying influence of genetic susceptibility on this relationship, Cox proportional hazards models were utilized.

RESULTS

During a median follow-up period of 14.55 years, 3,965 incident dementia cases were documented. CircS was found to significantly increased the risk of incident dementia, with a hazard ratio (HR) of 1.401 (95 % confidence interval [CI]: 1.296, 1.516). Compared to a CircS score of ≤3, mild CircS (HR: 1.259, 95 % CI: 1.146-1.383), moderate CircS (HR: 1.667, 95 % CI: 1.461-1.903), and severe CircS (HR: 2.028, 95 % CI: 1.397-2.944) were all significantly associated with an elevated risk of dementia. There were significant multiplicative interactions between CircS and genetic susceptibility (Pinteraction<0.001). Participants with both a high polygenic risk score (PRS) and CircS had the highest risk of incident dementia (HR: 2.551, 95 % CI: 2.169, 3.001), compared to those with a low PRS and no CircS.

CONCLUSIONS

CircS was associated with an increased risk of dementia, which might be aggravated by genetic susceptibility.

Evaluating the causal effects of circulating metabolic biomarkers on Alzheimer's disease

BACKGROUND

The diagnosis and treatment of Alzheimer's disease (AD) is challenging due to the complexity of its pathogenesis. Although research suggests a link between circulating metabolites and AD, their causal relationship is not fully understood.

METHODS

Based on publicly available genome-wide association study data, we investigated the causative relationship between AD (7759 cases and 334,740 controls) and 233 traits describing circulating metabolites (136,016 participants) using a two-sample Mendelian randomization (MR) method. We adopted the inverse variance weighted approach as the priority and performed sensitivity analyses with MR-Egger intercept method and Cochran's Q test.

RESULTS

The overall causal effect of circulating metabolic traits on AD was significantly higher than the inverse effect (beta: 0.15 ± 0.42 vs. 0.04 ± 0.07; p < 0.05). A total of 72 circulating metabolic traits (odd ratio (OR): 1.16-2.48) had a significant positive causal effect on AD, while a total of 16 circulating metabolic traits with significant negative causal effects on AD were detected (OR: 0.38-0.88). AD had a significant positive causal effect (OR: 1.02-1.17) on 142 circulating metabolic traits and a negative causal effect (OR: 0.87-0.99) on 43 circulating metabolic traits. Circulating metabolites that have a bi-directional causative relationship with AD mainly include apolipoprotein B levels, total cholesterol levels, total triglycerides levels, and omega-6 fatty acids levels.

CONCLUSION

The causative relationship between AD and the circulating metabolic traits is complex and bidirectional. Analyzing metabolites causally involved in the development of AD may provide clues for identifying preventive and therapeutic targets for this disorder.

Assessing the causal role of lipid metabolites in Alzheimer's disease: A mendelian randomization study

BACKGROUND

The causal relationship between lipid metabolites and Alzheimer's disease (AD) remains unclear and contradictory. This study aimed to systematically assess the causal relationship between lipid metabolites and AD.

METHODS

A two-step bidirectional Mendelian Randomization (MR) study was employed. The principal analytical technique used to evaluate causation was inverse variance weighting (IVW). Furthermore, mediation analysis was conducted to evaluate the possible function of lipidomes as mediators in the lipid-AD pathway.

RESULTS

Among the 213 lipid metabolites analyzed, significant causal associations with AD were identified Cholesterol esters in large LDL(L-LDL-CE) (OR = 1.236, 95 %CI = 1.052-1.453, P = 0.010), Total cholesterol in large LDL(L-LDL-TC) (OR = 1.506, 95 %CI = 1.235-1.835, P < 0.001), Total cholesterol in medium LDL(M-LDL-TC) (OR = 1.378, 95 %CI = 1.132-1.677, P = 0.001). Mediation analysis further revealed ceramide (d42:2) and phosphatidylinositol (PI) (18:1_18:1) as potential mediators in this relationship.

CONCLUSION

The identification of specific lipid metabolites with causal effects on AD provides new insights into AD pathogenesis and highlights potential targets for preventive strategies.

Apolipoproteins in Psoriasis: The Effect of Acitretin Treatment and UVB Phototherapy

BACKGROUND

Psoriasis is a chronic, multi-system inflammatory disease frequently associated with metabolic syndrome and lipid disturbances. Apolipoproteins, as essential regulators of lipid metabolism, may play a critical role in these metabolic abnormalities, potentially influencing disease severity and systemic inflammation. The aim of this study was to compare serum concentrations of chosen apolipoproteins in patients with psoriasis before and after treatment with acitretin or narrowband UVB (NB-UVB).

METHODS

This study was conducted on 39 patients with psoriasis. The concentration of nine apolipoproteins and C-reactive protein was quantified using the Bio-Plex Immunoassay Kit.

RESULTS

The serum concentrations of ApoA2, ApoC1, ApoD, ApoE, and ApoJ were higher in the acitretin group compared to the NB-UVB group before treatment, while the ApoA1/ApoA2 ratio was lower. We also observed a negative association between the Psoriasis Area and Severity Index (PASI) and ApoA1/ApoA2 ratio in the patients before the treatment.

CONCLUSIONS

The results of this study confirm the presence of metabolic disturbances in psoriatic patients. The treatment with NB-UVB or acitretin did not cause any significant changes in the apolipoproteins profile. Thus, we found no detrimental impact of acitretin on the apolipoproteins profile, despite the observed rise in total cholesterol concentration after the treatment. Further research is needed to explore whether specific therapeutic approaches can modify these disturbances and potentially improve long-term cardiovascular outcomes in this population.

Deep plasma and tissue proteome profiling of knockout mice reveals pathways associated with Svep1 deficiency

Despite strong causal associations with cardiovascular and metabolic disorders including coronary artery disease, hypertension, and type 2 diabetes, as well as a range of other diseases, the exact function of the protein SVEP1 remains largely unknown. Animal models have been employed to investigate how SVEP1 contributes to disease, with a focus on murine models exploring its role in development, cardiometabolic disease and platelet biology. In this study, we aimed to comprehensively phenotype the proteome of Svep1 +/- mice compared to wild-type (WT) littermates using liquid chromatography-tandem mass spectrometry (LC-MS/MS) bottom-up proteomics in plasma, heart, aorta, lung, and kidney to identify dysregulated pathways and biological functions associated with Svep1 deficiency. Our findings reveal that Svep1 deficiency leads to significant proteomic alterations across the mouse, with the highest number of dysregulated proteins observed in plasma and kidney. Key dysregulated proteins in plasma include upregulation of ADGRV1, CDH1, and MYH6, and downregulation of MTIF2 and AKAP13 which, alongside other proteins dysregulated across tissues, indicate disruption in cell adhesion, extracellular matrix organisation, platelet degranulation, and Rho GTPase pathways. Novel findings include significant enrichment of complement cascades in plasma, suggesting dysregulation of innate immune responses and hemostasis due to Svep1 deficiency. Pathways related to chylomicron assembly and lipid metabolism were also enriched. Additionally, we developed a high-throughput quantitative targeted LC-MS/MS assay to measure endogenous levels of murine SVEP1. SVEP1 was detectable in lung homogenate and showed a significant reduction in SVEP1 levels in Svep1 +/- vs. WT, but was not identified in plasma, heart, aorta, or kidney, likely due to expression levels below the assay's detection limit. Overall, this deep phenotyping study provides insight into the systemic impact of Svep1 deficiency.

Heterogeneous blood pressure treatment effects on cognitive decline in type 2 diabetes: A machine learning analysis of a randomized clinical trial

AIM

We aimed to identify the characteristics of patients with diabetes who can derive cognitive benefits from intensive blood pressure (BP) treatment using machine learning methods.

MATERIALS AND METHODS

Using data from the Action to Control Cardiovascular Risk in Diabetes Memory in Diabetes (ACCORD-MIND) study, 1349 patients with type 2 diabetes who underwent BP treatment (intensive treatment targeting a systolic BP <120 mmHg vs. standard treatment targeting <140 mmHg) were included in the machine learning analysis. Seventy-nine variables correlated with diabetes and cognitive function were used to build the causal forest and causal tree models for identifying heterogeneous BP treatment effects on cognitive decline.

RESULTS

Our analyses identified four variables including urinary albumin-to-creatinine ratio (UACR, mg/g), Framingham 10-year cardiovascular risk score (FRS, %), triglycerides (TG, mmol/L) and diabetes duration, that categorized the participants into five subgroups with different risk benefits for cognitive decline from BP treatments. Subgroup 1 (UACR ≥65 mg/g) had an absolute risk reduction (ARR) of 15.36% (95% CI, 5.01%-25.46%) from intensive versus standard BP treatment (hazard ratio [HR], 0.36; 95% CI, 0.18-0.73). Subgroup 2 (UACR <65 mg/g, FRS ≥26%, TG <2.3 mmol/L and diabetes duration ≥9 years) had an ARR of 14.74% (95% CI, 4.56%-24.59%) from intensive versus standard BP treatment (HR, 0.34; 95% CI, 0.15-0.77). No significant benefits were found for other subgroups.

CONCLUSIONS

Patients with type 2 diabetes with high UACR, or with low UACR and low TG, but high predicted cardiovascular risk and long diabetes duration were likely to derive cognitive benefits from intensive BP treatment.

Post-cardiovascular disease healthy lifestyle, inflammation and metabolic biomarkers, and risk of dementia: a population-based longitudinal study

BACKGROUND

Cardiovascular disease (CVD) is associated with an increased risk of dementia, but the impact of healthy lifestyle on post-CVD dementia remains unclear.

OBJECTIVES

The aim of this study was to explore the association between post-CVD healthy lifestyle factors and risk of dementia. We further examined whether inflammation and metabolic biomarkers played a role in this association.

METHODS

This prospective cohort study included 77,324 dementia-free participants with prevalent CVD from the UK Biobank. We constructed the lifestyle score based on no current smoking, moderate alcohol consumption, regular physical activity, healthy diet, adequate sleep duration, less sedentary behavior, and frequent social contact. Cox proportional hazard models were performed to examine the association of healthy lifestyle with risk of CVD-related dementia. Mediation models were fitted to investigate the underlying mechanisms driven by systemic inflammation, lipid profiles, liver/renal function, and blood pressure indices.

RESULTS

Over a median follow-up of 12.43 y, 1605 all-cause dementia (ACD) cases were documented, including 646 Alzheimer's dementia (AD) cases and 427 vascular dementia (VaD) cases. Healthy lifestyle scores were significantly associated with lower risk of dementia. The hazard ratios and 95% confidence intervals for the participants with 6-7 healthy lifestyle score were 0.50 (0.40, 0.62) for ACD, 0.80 (0.58, 1.10) for AD, and 0.30 (0.19, 0.48) for VaD, compared their counterpart with 0-1 score. Low-grade inflammatory markers and specific metabolic biomarkers were detected to significantly mediated the observed associations, explaining 1%∼11% of the associations of healthy lifestyle factors with dementia risk.

CONCLUSIONS

Adherence to healthy lifestyle behaviors is significantly associated with a lower risk of dementia in individuals with CVD. The observed associations may be partly explained by a reduction in systemic inflammation and the promotion of metabolic balance.

Early detection of Parkinson's disease through multiplex blood and urine biomarkers prior to clinical diagnosis

Blood and urine biomarkers are commonly used to diagnose and monitor chronic diseases. We initially screened 67 biomarkers, including 4 urine biomarkers and 63 blood biomarkers, and identified 13 blood biomarkers significantly associated with Parkinson's disease (PD). Among these, we discovered three novel markers demonstrating strong associations: phosphate (P = 1.81 × 10-3), AST/ALT ratio (P = 8.53 × 10-6), and immature reticulocyte fraction (IRF) (P = 3.49 × 10-20). We also substantiated eight well-studied biomarkers and elucidated the roles of two previously ambiguous biomarkers. Our analyses confirmed IGF-1 (P = 7.46 × 10-29) as a risk factor, and C-reactive protein (CRP) (P = 1.43 × 10-3) as protective against PD. Genetic analysis highlighted that IRF, CRP, and IGF-1 share significant genetic loci with PD, notably at MAPT, SETD1A, HLA-DRB1, and HLA-DQA1. Furthermore, Mendelian randomization (MR) analysis suggested potential causal associations between IGF-1, CRP, and PD. We identified several blood biomarkers that may be associated with the risk of developing PD, providing valuable insights for further exploration of PD-related biomarkers.

Independent associations of high-density lipoprotein cholesterol and triglyceride levels with Alzheimer's disease and related dementias

INTRODUCTION

We evaluated the independent associations between high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) levels with Alzheimer's disease and related dementias (ADRD).

METHODS

Among 177,680 members of Kaiser Permanente Northern California who completed a survey on health risks, we residualized TGs and HDL-C conditional on age, sex, and body mass index. We included these residuals individually and concurrently in Cox models predicting ADRD incidence.

RESULTS

Low (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.02-1.10) and high quintiles (HR 1.07, 95% CI 1.03-1.12) of HDL-C residuals were associated with an increased risk of ADRD compared to the middle quintile. Additional adjustment for TGs attenuated the association with high HDL-C (HR 1.03, 95% CI 0.99-1.08). Low TG residuals were associated with an increased ADRD risk (HR 1.10, 95% CI 1.06-1.15); high TG residuals were protective (HR 0.92, 95% CI 0.88-0.96). These estimates were unaffected by HDL-C adjustment.

DISCUSSION

Low HDL-C and TG levels are independently associated with increased ADRD risk. The correlation with low TG level explains the association of high HDL-C with ADRD.

HIGHLIGHTS

Strong correlations between lipid levels are important considerations when investigating lipids as late-life risk factors for Alzheimer's disease and related dementias (ADRD). Low levels of high-density lipoprotein cholesterol (HDL-C) and triglycerides (TGs) were independently associated with an increased risk of ADRD. We found no evidence for an association between high HDL-C and increased ADRD risk after adjustment for TGs. High levels of TGs were consistently associated with a decreased risk of ADRD. There may be interaction between TG and HDL-C levels, where both low HDL-C and TG levels increase the risk of ADRD compared to average levels of both.

The causal role of lipids in dementia: A Mendelian randomization study

Background

Increasing evidence suggests that abnormal lipid metabolism is one of the pathogeneses of dementia. It is necessary to reveal the relationship between lipids and dementia.

Objective

This study used bidirectional two-sample Mendelian randomization to explore the causal relationship between 179 lipid species and the risk of dementia.

Methods

We assessed the causal effects of 179 lipid species and four subtypes of dementia including Alzheimer's disease (AD), vascular dementia (VaD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB). Inverse variance weighting, MR-Egger method, weighted median, simple mode, and weighted mode were used to analyze the relationship between lipids and dementia. Cochran's Q, MR-Egger intercept test, and MR-PRESSO test were used to test the heterogeneity and pleiotropy of the results. In addition, we performed an inverse MR analysis testing the causal effects of dementia on lipids.

Results

Our study revealed causal effects of glycerophospholipid, glycerolipid, and sterol on the risk of dementia. Phosphatidylcholine, phosphatidylinositol, and triglycerides play significant roles in AD. Notably, phosphatidylcholine played a protective role in both FTD and DLB. However, this study did not observe a significant effect of phosphatidylinositol on FTD. In the case of VaD, not only glycerophospholipid, but also glycerolipid, exerted an influence, but sterol was also a risk factor.

Conclusions

Our study provided new evidence supporting the causal role of genetically predicted lipid species in dementia. Future clinical trials are necessary to evaluate the potential role of lipid levels in dementia prevention.

Serum metabolome profiling in patients with mild cognitive impairment reveals sex differences in lipid metabolism

Alzheimer's disease (AD) affects more women than men. Although women live longer than men, it is not longevity alone, but other factors, including metabolic changes, that contribute to the higher risk of AD in women. Metabolic pathways have been implicated in AD progression, but studies to date examined targeted pathways, leaving many metabolites unmeasured. Sex is often a neglected biological variable, and most metabolomic studies were not designed to investigate sex differences in metabolomic profiles. Here, we performed untargeted metabolomic profiling of sera from male and female patients with mild cognitive impairment (MCI), a common precursor to AD, and matched controls. We discovered significant metabolic changes in individuals with MCI, and found several pathways that were strongly associated with sex. Peptide energy metabolism demonstrated sexual dimorphism. Lipid pathways exhibited the strongest differences between female and male MCI patients, including specific phosphatidylcholine lipids, lysophospholipids, long-chain fatty acids, and monoacylglycerols. 1-palmitoleoyl glycerol and 1-arachidonoyl glycerol were higher in female MCI subjects than in male MCI subjects with no differences between control males and females. Conversely, specific dicarboxylic fatty acids were lower in female MCI subjects than male MCI subjects. In cultured astrocytes, 1-arachidonoyl glycerol promoted phosphorylation of the transcriptional regulator sphingosine kinase 2, which was inhibited by the transient receptor potential vanilloid 1 receptor antagonists, as well as chromatin remodelling. Overall, we identified novel sex-specific metabolites in MCI patients that could serve as biomarkers of MCI in both sexes, help further define AD etiology, and reveal new potential prevention strategies for AD.

Blood RNA transcripts show changes in inflammation and lipid metabolism in Alzheimer's disease and mitochondrial function in mild cognitive impairment

Background

Abnormal immunity in the periphery has been reported in the pathogenesis of Alzheimer's disease (AD).

Objective

In this study, blood transcriptome analyses of patients with AD, those with mild cognitive impairment (MCI) due to AD, and heathy controls were performed to elucidate immune-related pathophysiology.

Methods

The sample included 63 participants from a complete enumeration study of elderly people in Nakayama town (the Nakayama Study), who were over 65 years of age, diagnosed as (1) healthy controls (N = 21, mean age: 83.8 years), (2) having MCI due to AD (N = 20, mean age: 82.6 years), or (3) having AD (N = 21, mean age: 84.2 years). Every participant underwent blood tests, magnetic resonance imaging, and questionnaires about lifestyle and cognitive function. With transcriptome analysis, differential gene expressions in the blood of the three groups were evaluated by gene ontology, pathway enrichment, and ingenuity pathway analyses, and quantitative real-time PCR was performed.

Results

Neutrophil extracellular trap signaling was increased, and lipid metabolism (FXR/RXR activation, triacylglycerol degradation) was decreased in AD, whereas MCI showed protective responses via decreased neutrophil extracellular trap signaling and mitochondrial functions such as upregulation of the sirtuin pathway and downregulation of oxidative stress.

Conclusions

Based on these findings and consistent with other published studies, immune cells appear to have important roles in the pathogenesis of AD, and the transcriptome in blood may be useful as a biomarker for diagnosis via monitoring immunity in MCI and AD.

The study on cuproptosis in Alzheimer's disease based on the cuproptosis key gene FDX1

Background

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory and cognitive impairments. Previous studies have shown neuronal death in the brains of AD patients, but the role of cuproptosis and its associated genes in AD neurons remains unclear.

Methods

Intersection analysis was conducted using the AD transcriptome dataset GSE63060, neuron dataset GSE147528, and reported cuproptosis-related genes to identify the cuproptosis key gene FDX1 highly expressed in AD. Subsequently, cell experiments were performed by treating SH-SY5Y cells with Aβ25-35 to establish AD cell model. The real-time reverse transcriptase-polymerase chain reaction (RT-qPCR) and western blotting (WB) assays were employed to detect the expression levels of FDX1, DLAT, and DLST. Cell proliferation was analyzed by counting Kit-8 (CCK8), mitochondrial ROS levels were analyzed using flow cytometry. shRNA was used to downregulate FDX1 expression, followed by repetition of the aforementioned experiments. Clinical experiments utilized qPCR to detect FDX1 mRNA levels in peripheral venous blood of patients, and analyzed FDX1 expression differences in different APOE genotypes of AD patients. Finally, a protein-protein interaction (PPI) network of FDX1 was constructed based on the GeneMANIA database, immune infiltration analysis was conducted using R language, and transcription factors prediction for FDX1 was performed based on the ENCODE database.

Results

The cuproptosis key gene FDX1 showed significantly higher expression in peripheral blood and neuron models of AD compared to non-AD individuals, with significantly higher expression in APOE ε4/ε4 genotype than other APOE genotype of AD patients. Knockdown of FDX1 expression reduced the lipidation levels of DLAT and DLST in neurons, alleviated ROS accumulation in mitochondria, improved cell viability, and mitigated cuproptosis. Immune infiltration analysis results indicated a high enrichment of peripheral blood γδ-T lymphocytes in AD, and FDX1 was significantly associated with the infiltration of four immune cells and may be regulated by three transcription factors.

Conclusion

The cuproptosis key gene FDX1 is highly expressed in AD and may promote cuproptosis in AD neurons by regulating the lipidation levels of DLAT and DLST, thereby participating in the onset and development of AD. This provides a potential target for the diagnosis and treatment of AD.

Associations of Serum Lipid Traits With Fracture and Osteoporosis: A Prospective Cohort Study From the UK Biobank

BACKGROUND

Previous studies reveal inconsistent associations between serum lipid traits and the risks of fractures and osteoporosis in the general population.

METHODS

This prospective cohort study analysed data from 414 302 UK Biobank participants (223 060 women and 191 242 men, aged 37-73 years) with serum lipid measurements: apolipoprotein A (Apo A), apolipoprotein B (Apo B), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and lipoprotein A (Lp(a)). Multivariable Cox proportional hazard models with penalized cubic splines were used to explore potential nonlinear associations of each lipid trait with the risks of fractures and osteoporosis. Subgroup analyses by age, sex, BMI categories and pre-existing cardiovascular disease were conducted. Mediation analyses using the g-formula were performed to quantify to which extent bone mineral density (BMD) may mediate the association between serum lipids and fracture risk.

RESULTS

Over a median follow-up period of 13.8 years, 25 918 (6.8%) of the 383 530 participants without prior fracture had incident fracture cases, and 7591 (4.1%) of the 184 919 participants with primary care data and without baseline osteoporosis were diagnosed with osteoporosis. TG had nonlinear associations with fractures and osteoporosis, whereas Apo B, TC and LDL-C had linear associations. There were also nonlinear associations of Apo A and HDL-C with fractures. Individuals in the highest quintiles for Apo A (fracture: HR 1.15 [95% CI 1.10, 1.21]; osteoporosis: HR 1.13 [1.02, 1.25]) and HDL-C (fracture: HR 1.27 [1.20, 1.34]; osteoporosis: HR 1.31 [1.18, 1.46]) were associated with higher risks of fractures and osteoporosis. Conversely, those in the highest quintile for Apo B (fracture: HR 0.85 [0.81, 0.89]; osteoporosis: HR 0.86 [0.79, 0.94]), LDL-C (fracture: HR 0.89 [0.85, 0.93]; osteoporosis: HR 0.91 [0.83, 1.00]) and TG (fracture: HR 0.78 [0.74, 0.82]; osteoporosis: HR 0.75 [0.68, 0.82]) were associated with lower risks. The associations of Apo A (ratio of HR [RHR] 1.05 [1.02, 1.09]) and HDL-C (RHR 1.06 [1.03, 1.09]) with fracture risk were more pronounced in men compared to women. Except for TG and Lp(a), the associations between serum lipids and fractures appear to be partially mediated through BMD (mediation proportions: 5.30% to 40.30%), assuming causality.

CONCLUSIONS

Our study reveals a complex interplay between different lipid markers and skeletal health, potentially partially mediated through BMD. Routine lipid profile assessments, including HDL-C and Apo A among other lipid traits, may be integrated into the strategies for fracture risk stratification.

Serum metabolome profiling in patients with mild cognitive impairment reveals sex differences in lipid metabolism

Alzheimer's disease (AD) affects more women than men. Although women live longer than men, it is not longevity alone, but other factors, including metabolic changes, that contribute to the higher risk of AD in women. Metabolic pathways have been implicated in AD progression, but studies to date examined targeted pathways, leaving many metabolites unmeasured. Sex is often a neglected biological variable, and most metabolomic studies were not designed to investigate sex differences in metabolomic profiles. Here, we performed untargeted metabolomic profiling of sera from male and female patients with mild cognitive impairment (MCI), a common precursor to AD, and matched controls. We discovered significant metabolic changes in individuals with MCI, and found several pathways that were strongly associated with sex. Peptide energy metabolism demonstrated sexual dimorphism. Lipid pathways exhibited the strongest differences between female and male MCI patients, including specific phosphatidylcholine lipids, lysophospholipids, long-chain fatty acids, and monoacylglycerols. 1-palmitoleoyl glycerol and 1-arachidonoyl glycerol were higher in female MCI subjects than in male MCI subjects with no differences between control males and females. Conversely, specific dicarboxylic fatty acids were lower in female MCI subjects than male MCI subjects. In cultured astrocytes, 1-arachidonoyl glycerol promoted phosphorylation of the transcriptional regulator sphingosine kinase 2, which was inhibited by the transient receptor potential vanilloid 1 receptor antagonists, as well as chromatin remodelling. Overall, we identified novel sex-specific metabolites in MCI patients that could serve as biomarkers of MCI in both sexes, help further define AD etiology, and reveal new potential prevention strategies for AD.

Lipids, lipoproteins, and apolipoproteins: Associations with cognition and dementia

Due to increasing lifespan and aging populations globally there has been a steep rise in late-life dementia, which is now the second most common cause of death in high-income countries. In general, dementia can be divided into two major groups: Alzheimer's disease (AD) and vascular-related dementia (VD). AD is pathologically characterised by senile plaques containing amyloid-β and neurofibrillary tangles composed of hyperphosphorylated tau, whereas VD is dominated by vascular pathology such as cerebral small vessel disease, major strokes, and white matter lesions. Recently, the importance of vascular components in AD is increasingly recognized and it is estimated that up to 45 % of all dementia cases can be prevented by preventing or treating midlife cardiovascular risk factors such as physical inactivity, diabetes, and hypertension. Even though the brain contains approximately 25 % of the total body cholesterol pool, and several genetic variants related to the lipid metabolism have been identified in genome-wide associations studies of AD, the role of lipids, lipoproteins, and apolipoproteins in dementia risk is less well-known. In this review, we go through the current literature on lipids, lipoproteins, and apolipoproteins and risk of dementia. We conclude that the evidence is primarily insufficient or conflicting, possibly due to nonoptimal study designs. The future calls for large, prospective studies of midlife measurements of lipids, lipoproteins, and apolipoproteins and one-sample, individual level data Mendelian randomization studies to overcome survival bias. However, the current literature suggests that it is safe to say that what is good for the heart is good for the brain.

Elevated blood glucose levels are associated with the progression of brain hypometabolism, and HDL-C and APOE4 add to this association

Background

Brain glucose hypometabolism has consistently been found in neurodegenerative disorders, including Alzheimer's disease (AD). High blood glucose and HDL cholesterol (HDL-C) levels have also been linked to neurodegeneration and AD. However, there is limited understanding of the relationships between dementia-related risk factors in the brain and blood.

Methods

A linear mixed model was used to examine the relationship between blood glucose and HDL-C levels and the progression of brain hypometabolism, adjusting for APOE4 and other clinical covariates. The hypometabolic convergence index (HCI) was measured by fluorodeoxyglucose-18 (FDG) positron emission tomography (PET) in participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Data visualizations were generated to understand the joint effects of plasma glucose, HDL-C, and APOE4 on HCI.

Results

There were 336 individuals (781 observations), of whom 22.62% had AD. The majority were male (63.98%) and of white race, and 48.51% were carriers of APOE4. Over time, high blood glucose level was associated with the progression of brain glucose hypometabolism (β=0.33, 95% CI: 0.02, 0.64, p<0.05). A high plasma HDL-C level (β=1.22, 95% CI: 0.09, 2.35, p<0.05), more study visits (β=1.67, 95% CI: 1.37, 1.98, p<0.001), and being an APOE4 allele carrier (β=1.29, 95% CI: 0.15, 2.42, p<0.05) were also significant predictors of brain hypometabolism progression. APOE4 carrier status and number of visits account for the largest proportion of the variance from the fixed effects model. Random effects due to participant characteristics and fixed effects together accounted for 95.2% of the model variance. Subgroup analysis revealed that these effects were observed only in those without AD.

Conclusion

High plasma glucose levels facilitated the progression of brain hypometabolism. The effect was more prominent in the APOE4 double-carriers with elevated HDL-C. Elevated blood glucose may reflect systemic insulin resistance, which could impair brain glucose uptake, resulting in brain hypometabolism. Controlling blood glucose and HDL-C levels in APOE4 carriers may improve brain metabolism, potentially delaying the onset of dementia.

Adverse Lipid Profiles Are Associated with Lower Dementia Risk in Older People

OBJECTIVE

Midlife dyslipidemia is associated with higher risk of dementia in late-life dementia, but the impact of late-life dyslipidemia on dementia risk is uncertain. This may be due to the large heterogeneity in cholesterol measures and study designs employed. We used detailed data from a large prospective cohort of older persons to comprehensively assess the relation between a broad range of cholesterol measures and incident dementia, addressing potential biases, confounders, and modifiers.

DESIGN

Post hoc observational analysis based on data from a dementia prevention trial (PreDIVA).

SETTING AND PARTICIPANTS

3392 community-dwelling individuals, without dementia, aged 70-78 years at baseline (recruited between June 2006 and March 2009).

METHODS

Total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides, and apolipoprotein A1 and B were assessed. Over a median of 6.7 years' follow-up, dementia was established by clinical diagnosis confirmed by independent outcome adjudication. Hazard ratios (HRs) for dementia and mortality were calculated using Cox regression.

RESULTS

Dementia occurred in 231 (7%) participants. One-SD increase in LDL/HDL conveyed a 19% (P = .01) lower dementia risk and a 10% (P = .02) lower risk of dementia/mortality combined. This was independent of age, cardiovascular risk factors, cognitive function, apolipoprotein E genotype, and cholesterol-lowering drugs (CLD). This association was not influenced by the competing risk of mortality. Consistent and significant interactions suggested these associations were predominant in individuals with low body mass index (BMI) and higher education.

CONCLUSIONS AND IMPLICATIONS

Dyslipidemia in older individuals was associated with a lower risk of dementia. Low BMI and higher education level mitigate poor outcomes associated with dyslipidemia. These findings suggest that a different approach may be appropriate for interpreting lipid profiles that are conventionally considered adverse in older adults. Such an approach may aid predicting dementia risk and designing intervention studies aimed at reducing dementia risk in older populations.

Hypercholesterolemia and the Increased Risk of Vascular Dementia: a Cholesterol Perspective

PURPOSE OF REVIEW

Vascular dementia (VaD) is the second most prevalent type of dementia after Alzheimer's disease.Hypercholesterolemia may increase the risk of dementia, but the association between cholesterol and cognitive function is very complex. From the perspective of peripheral and brain cholesterol, we review the relationship between hypercholesterolemia and increased risk of VaD and how the use of lipid-lowering therapies affects cognition.

RECENT FINDINGS

Epidemiologic studies show since 1980, non-HDL-C levels of individuals has increased rapidly in Asian countries.The study has suggested that vascular risk factors increase the risk of VaD, such as disordered lipid metabolism. Dyslipidemia has been found to interact with chronic cerebral hypoperfusion to promote inflammation resulting in cognitive dysfunction in the brain.Hypercholesterolemia may be a risk factor for VaD. Inflammation could potentially serve as a link between hypercholesterolemia and VaD. Additionally, the potential impact of lipid-lowering therapy on cognitive function is also worth considering. Finding strategies to prevent and treat VaD is critical given the aging of the population to lessen the load on society. Currently, controlling underlying vascular risk factors is considered one of the most effective methods of preventing VaD. Understanding the relationship between abnormal cholesterol levels and VaD, as well as discovering potential serum biomarkers, is important for the early prevention and treatment of VaD.

Nonlinear relationship between triglycerides and cognitive function after acute ischemic stroke among older adults

Background

Although studies have explored the association between triglyceride levels and cognitive function after acute ischemic stroke (AIS), the results have been conflicting. Therefore, the purpose of this study was to investigate the relationship between triglyceride levels and cognitive function after AIS among older adults.

Methods

This is an observational cross-sectional study. From November 2022 to June 2023, we consecutively collected patients diagnosed with AIS in China. Triglyceride levels were measured within 24 h of admission. The Mini-Mental State Examination (MMSE) was used to assess cognitive function. Nonlinear associations between triglyceride levels and cognitive function were assessed using smooth curve fitting and threshold effect analysis.

Results

In this study, a total of 221 patients (mean ± SD: 70.64 ± 7.43 years) with AIS were consecutively recruited, among whom 144 (65.16%) were male. Among the 221 recruited patients, 102 (46.15%) had cognitive impairment. Triglyceride levels and cognitive impairment were found to have a nonlinear association after controlling for potential confounders, with an inflection point at 0.8 mmol/L. Below the inflection point, triglyceride levels were positively correlated with MMSE scores (β = 14.11, 95% confidence interval [CI] = 2.33-25.89, P = 0.020). However, above the inflection point, the correlation between MMSE score and triglyceride levels was not statistically significant (β = 1.04, 95% CI = -1.27 - 3.34, P = 0.380).

Conclusion

There is a nonlinear association between triglyceride levels and cognitive function after AIS in older adults. Triglyceride was positively connected with cognitive function when it was less than 0.8 mmol/L.

Associations of Triglycerides and Atherogenic Index of Plasma with Brain Structure in the Middle-Aged and Elderly Adults

Triglyceride (TG) and atherogenic index of plasma (AIP) have been acknowledged to be risk factors for vascular insults, but their impacts on the brain system remain elusive. To fill in some gaps, we investigated associations of TG and AIP with brain structure, leveraging the UK Biobank database. TG and high-density lipoprotein cholesterol (HDL-C) were examined at baseline and AIP was calculated as log (TG/HDL-C). We build several linear regression models to estimate associations of TG and AIP with volumes of brain grey matter phenotypes. Significant inverse associations of TG and AIP with volumes of specific subcortical traits were observed, among which TG and AIP were most significantly associated with caudate nucleus (TG: β [95% confidence interval CI] = -0.036 [-0.051, -0.022], AIP: -0.038 [-0.053, -0.023]), thalamus (-0.029 [-0.042, -0.017], -0.032 [-0.045, -0.019]). Higher TG and AIP were also considerably related with reduced cortical structure volumes, where two most significant associations of TG and AIP were with insula (TG: -0.035 [-0.048, -0.022], AIP: -0.038 [-0.052, -0.025]), superior temporal gyrus (-0.030 [-0.043, -0.017], -0.033 [-0.047, -0.020]). Modification effects of sex and regular physical activity on the associations were discovered as well. Our findings show adverse associations of TG and AIP with grey matter volumes, which has essential public health implications for early prevention in neurodegenerative diseases.

Association between metabolic syndrome and risk of incident dementia in UK Biobank

INTRODUCTION

The association between metabolic syndrome (MetS) and incident dementia remains inconclusive.

METHODS

In 176,249 dementia-free UK Biobank participants aged ≥60 years at baseline, Cox proportional-hazards models were used to investigate the association between MetS and incident dementia. MetS was defined as the presence of ≥3 of the following: elevated waist circumference, triglycerides, blood pressure, blood glucose, and reduced high-density lipoprotein cholesterol.

RESULTS

Over 15 years of follow-up (median = 12.3), 5255 participants developed dementia. MetS was associated with an increased risk of incident dementia (hazard ratio [HR]: 1.12, 95% confidence interval [CI]: 1.06, 1.18). The association remained consistent when restricting to longer follow-up intervals: >5 to 10 years (HR: 1.17, 95% CI: 1.07, 1.27) and >10 years (HR: 1.22, 95% CI: 1.12, 1.32). Stronger associations were observed in those with ≥4 MetS components and in apolipoprotein-E (APOE)-ε4 non-carriers.

DISCUSSION

In this large population-based prospective cohort, MetS was associated with an increased risk of dementia.

HIGHLIGHTS

MetS was associated with a 12% increased risk of incident all-cause dementia. Associations remained similar after restricting the analysis to those with longer follow-up. The presence of four or five MetS components was significantly associated with dementia. Stronger associations were observed in those with a low genetic risk for dementia.

Measuring lipoprotein(a) for cardiovascular disease prevention - in whom and when?

PURPOSE OF REVIEW

The aim of this study is to summarize major cardiovascular guideline recommendations on lipoprotein(a) and highlighting recent findings that emphasize how measuring lipoprotein(a) once in all adults is meaningful regardless of age, sex, comorbidities, or ethnicity.

RECENT FINDINGS

Many international guidelines now recommend once in a lifetime measurement of lipoprotein(a) in all adult individuals to facilitate accurate risk prediction. Lipoprotein(a)-lowering therapy to reduce cardiovascular disease is on the horizon, with results from the first phase 3 trial expected in 2025.

SUMMARY

Elevated lipoprotein(a) is an independent causal risk factor for atherosclerotic cardiovascular disease and aortic valve stenosis and measuring lipoprotein(a) once in all individuals regardless of age, sex, comorbidities, or ethnicity is meaningful to aid in risk stratification.

Correlation Analysis of ApoB, ApoA1, and ApoB/ApoA1 with Cortical Morphology in Patients with Memory Complaints

Background

Apolipoproteins and cortical morphology are closely associated with memory complaints, and both may contribute to the development of Alzheimer's disease.

Objective

To examine whether apolipoprotein B (ApoB), apolipoprotein A-1 (ApoA1), and their ratio (ApoB/ApoA1) are associated with cortical morphology in patients with memory complaints.

Methods

Ninety-seven patients underwent neuropsychological testing, measurements of ApoB, ApoA1, ApoB/ApoA1, plasma Alzheimer's biomarker, apolipoprotein E (ApoE) genotyping, and 3T structural magnetic resonance imaging (sMRI) scans. Based on sMRI scanning locations, patients were categorized into the University of Electronic Science and Technology (UESTC) and the Fourth People's Hospital of Chengdu (FPHC). The Computational Anatomy Toolbox within Statistical Parametric Mapping was used to calculate each patient's cortical morphology index based on sMRI data. The cortical morphology index and apolipoproteins were also analyzed.

Results

Significant positive correlations were found between ApoB and sulcal depth in the lateral occipital cortex among the UESTC, the FPHC, and the total sample groups, and negative correlations were observed between sulcal depth in the lateral occipital cortex and the scores of the Shape Trails Test Part A and B. In the FPHC group, the scores of the Montreal Cognitive Assessment Basic, delayed recall of the Auditory Verbal Learning Test, Animal Fluency Test and Boston Naming Test were positively correlated with the sulcal depth.

Conclusions

ApoB is associated with the sulcal depth in the lateral occipital cortex, potentially relating to speed/executive function in individuals with memory complaints.

Sex-specific blood biomarkers linked to memory changes in middle-aged adults: The Framingham Heart Study

The relationship between sex-specific blood biomarkers and memory changes in middle-aged adults remains unclear. We aimed to investigate this relationship using the data from the Framingham Heart Study (FHS). We conducted association analysis, partial correlation analysis, and causal dose-response curves using blood biomarkers and other data from 793 middle-aged participants (≤ 60 years) from the FHS Offspring Cohort. The results revealed associations of adiponectin and fasting blood glucose with midlife memory change, along with a U-shaped relationship of high-density lipoprotein cholesterol with memory change. No significant associations were found for the other blood biomarkers (e.g., amyloid beta protein 42) with memory change. To our knowledge, this is the first sex-specific network analysis of blood biomarkers related to midlife memory change in a prospective cohort study. Our findings highlight the importance of targeting cardiometabolic risks and the need to validate midlife-specific biomarkers that can accelerate the development of primary preventive strategies.

Change in lipids before onset of dementia, coronary heart disease, and mortality: A 28-year follow-up Whitehall II prospective cohort study

INTRODUCTION

The association of lipids with dementia remains a subject of debate. Using data from 7,672 participants of the Whitehall II prospective cohort study, we examined whether timing of exposure, length of follow-up, or sex modifies this association.

METHODS

Twelve markers of lipid levels were measured from fasting blood and eight among them a further five times. We performed time-to-event as well as trajectory analyses.

RESULTS

No associations were observed in men; in women most lipids were associated with the risk of dementia, but only for events occurring after the first 20 years of follow-up. Differences in lipid trajectories in men emerged only in the years immediately before diagnosis whereas in women total cholesterol (TC), LDL-cholesterol (LDL-C), non-HDL-cholesterol (non-HDL-C), TC/HDL-C, and LDL-C/HDL-C were higher in midlife among dementia cases before declining progressively.

DISCUSSION

Abnormal lipid levels in midlife seem to be associated with a higher risk of dementia in women.

Circulating metabolites and risk of incident dementia: A prospective cohort study

Identifying circulating metabolites associated with dementia, cognition, and brain volume may improve the understanding of dementia pathogenesis and provide novel insights for preventive and therapeutic interventions. This cohort study included a total of 87 885 participants (median follow-up of 9.1 years, 54% female) without dementia at baseline from the UK Biobank. A total of 249 plasma metabolites were measured using nuclear magnetic resonance spectroscopy at baseline. Cox proportional regression was used to examine the associations of each metabolite with incident dementia (cases = 1134), Alzheimer's disease (AD; cases = 488), and vascular dementia (VD; cases = 257) during follow-up. Dementia-associated metabolites were further analyzed for association with cognitive deficits (N = 87 885) and brain volume (N = 7756) using logistic regression and linear regression. We identified 26 metabolites associated with incident dementia, of which 6 were associated with incident AD and 5 were associated with incident VD. These 26 dementia-related metabolites were subfractions of intermediate-density lipoprotein, large low-density lipoprotein (L-LDL), small high-density lipoprotein (S-HDL), very-low-density lipoprotein, fatty acids, ketone bodies, citrate, glucose, and valine. Among them, the cholesterol percentage in L-LDL (L-LDL-C%) was associated with lower risk of AD (HR [95% CI] = 0.92 [0.87-0.97], p = 0.002), higher brain cortical (β = 0.047, p = 3.91 × 10-6 ), and hippocampal (β = 0.043, p = 1.93 × 10-4 ) volume. Cholesteryl ester-to-total lipid ratio in L-LDL (L-LDL-CE%) was associated with lower risk of AD (HR [95% CI] = 0.93 [0.90-0.96], p = 1.48 × 10-4 ), cognitive deficits (odds ratio = 0.98, p = 0.009), and higher hippocampal volume (β = 0.027, p = 0.009). Cholesteryl esters in S-HDL (S-HDL-CE) were associated with lower risk of VD (HR [95% CI] = 0.81 [0.71-0.93], p = 0.002), but not AD. Taken together, circulating levels of L-LDL-CE% and L-LDL-C% were robustly associated with risk of AD and AD phenotypes, but not with VD. S-HDL-CE was associated with lower risk of VD, but not with AD or AD phenotypes. These metabolites may play a role in the advancement of future intervention trials. Additional research is necessary to gain a complete comprehension of the molecular mechanisms behind these associations.

Association Between Triglycerides and Risk of Dementia in Community-Dwelling Older Adults: A Prospective Cohort Study

BACKGROUND AND OBJECTIVES

It has been suggested that higher triglyceride levels were associated with a lower risk of Alzheimer disease. This study aimed to examine the association of triglycerides with dementia and cognition change in community-dwelling older adults.

METHODS

This prospective longitudinal study used data from the Aspirin in Reducing Events in the Elderly (ASPREE) randomized trial of adults aged 65 years or older without dementia or previous cardiovascular events at enrollment. The main outcome was incident dementia. Other outcomes included changes in composite cognition and domain-specific cognition (global cognition, memory, language and executive function, and psychomotor speed). The association between baseline triglycerides and dementia risk was estimated using Cox proportional hazard models adjusting for relevant risk factors. Linear mixed models were used to investigate cognitive change. The analysis was repeated in a subcohort of participants with available APOE-ε4 genetic data with additional adjustment for APOE-ε4 carrier status and an external cohort (UK Biobank) with similar selection criteria applied.

RESULTS

This study included 18,294 ASPREE participants and 68,200 UK Biobank participants (mean age: 75.1 and 66.9 years; female: 56.3% and 52.7%; median [interquartile range] triglyceride: 106 [80-142] mg/dL and 139 [101-193] mg/dL), with dementia recorded in 823 and 2,778 individuals over a median follow-up of 6.4 and 12.5 years, respectively. Higher triglyceride levels were associated with lower dementia risk in the entire ASPREE cohort (hazard ratio [HR] with doubling of triglyceride: 0.82, 95% CI 0.72-0.94). Findings were similar in the subcohort of participants with APOE-ε4 genetic data (n = 13,976) and in the UK Biobank cohort (HR was 0.82 and 0.83, respectively, all p ≤ 0.01). Higher triglycerides were also associated with slower decline in composite cognition and memory over time (p ≤ 0.05).

DISCUSSION

Older adults with higher triglyceride levels within the normal to high-normal range had a lower dementia risk and slower cognitive decline over time compared with individuals with lower triglyceride levels. Higher triglyceride levels may be reflective of better overall health and/or lifestyle behaviors that would protect against dementia development. Future studies are warranted to investigate whether specific components within the total circulating pool of plasma triglycerides may promote better cognitive function, with the hope of informing the development of new preventive strategies.

High ApoB/ApoA-I Ratio Predicts Post-Stroke Cognitive Impairment in Acute Ischemic Stroke Patients with Large Artery Atherosclerosis

BACKGROUND

We aimed to investigate the association between the ApoB/ApoA-I ratio and post-stroke cognitive impairment (PSCI) in patients with acute stroke of large artery atherosclerosis etiology.

METHODS

Prospective stroke registry data were used to consecutively enroll patients with acute ischemic stroke due to large artery atherosclerosis. Cognitive function assessments were conducted 3 to 6 months after stroke. PSCI was defined as a z-score of less than -2 standard deviations from age, sex, and education-adjusted means in at least one cognitive domain. The ApoB/ApoA-I ratio was calculated, and patients were categorized into five groups according to quintiles of the ratio. Logistic regression analyses were performed to assess the association between quintiles of the ApoB/ApoA-I ratio and PSCI.

RESULTS

A total of 263 patients were included, with a mean age of 65.9 ± 11.6 years. The median NIHSS score and ApoB/ApoA-I ratio upon admission were 2 (IQR, 1-5) and 0.81 (IQR, 0.76-0.88), respectively. PSCI was observed in 91 (34.6%) patients. The highest quintile (Q5) of the ApoB/ApoA-I ratio was a significant predictor of PSCI compared to the lowest quintile (Q1) (adjusted OR, 3.16; 95% CI, 1.19-8.41; p-value = 0.021) after adjusting for relevant confounders. Patients in the Q5 group exhibited significantly worse performance in the frontal domain.

CONCLUSIONS

The ApoB/ApoA-I ratio in the acute stage of stroke independently predicted the development of PSCI at 3-6 months after stroke due to large artery atherosclerosis. Further, a high ApoB/ApoA-I ratio was specifically associated with frontal domain dysfunction.

Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium

INTRODUCTION

Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups.

METHODS

A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta-analysis. Sex-specific hazard ratios (HRs), and women-to-men ratio of hazard ratios (RHRs) for associations between RFs and all-cause dementia were derived from mixed-effect Cox models.

RESULTS

Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low- and lower-middle-income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs.

DISCUSSION

Dementia risk was higher in women than men, with possible variations by country-level income settings, but most RFs appear to work similarly in women and men.