Association between plasma copper levels and first stroke: a community-based nested case-control study

Association of plasma metals with resting-state functional connectivity in ischemic stroke

BACKGROUND

Metal exposure has long been considered a significant risk factor for ischemic stroke. However, existing data on the effects of metal exposure on brain function in ischemic stroke are limited. Therefore, this study aimed to explore the correlation between exposure to various metals and changes in resting-state functional connectivity (rs-FC) in ischemic stroke patients.

METHODS

This study included 28 acute ischemic stroke patients with hemiplegia and 28 matched healthy controls (HCs). All participants underwent T1-weighted MRI and 3.0 T resting-state functional magnetic resonance imaging (fMRI). After MRI acquisition, the rs-FC between 137 cortical and subcortical regions was extracted and preprocessed. Plasma levels of 19 metals were measured using inductively coupled plasma mass spectrometry (ICP-MS). The Bayesian kernel machine regression (BKMR) model and the weighted quantile sum regression (WQS) model were used to assess the overall effect of metal mixture exposure. The severity of neurological deficits in each acute ischemic stroke patient was evaluated using the National Institutes of Health Stroke Scale (NIHSS). Additionally, the associations between exposure to various metals and modifications in brain functional connectivity were determined using Pearson or Spearman correlation analysis.

RESULTS

Bilateral brain connectivity was significantly decreased compared to controls and was associated with neurological impairment in ischemic stroke. In patients with ischemic stroke, the plasma concentrations of Cr (p < 0.001), Cu (p = 0.004), As (p = 0.010), Cs (p = 0.046), Rb (p = 0.041), and Sb (p = 0.001) were significantly higher than those in the HCs, whereas the plasma Tl concentrations (p = 0.022) were significantly lower. The results of the BKMR and WQS models showed that combined exposure to metal mixtures was linked to a higher risk of ischemic stroke. Cr was positively correlated with the rs-FC between the left Rolandic_Oper and the left Supp_Motor_Area (r = 0.414, p = 0.029), while negatively correlated with the rs-FC between the right Parietal_Inf and the left supramarginal (r = -0.398, p = 0.037). Cu was negatively correlated with the rs-FC between the left paracentral lobule and the left thalamus (r = -0.409, p = 0.031). Tl was positively correlated with the rs-FC between the right Parietal_Inf and the left supramarginal cortex (r = 0.590, p = 0.001). A negative correlation was observed between Cs and rs-FC between the right Cingulate_Mid and left Occipital_Sup (r = -0.429, p = 0.024). Sb was negatively correlated with the rs-FC between the left Parietal_Inf and the right SupraMarginal (r = -0.384, p = 0.044), the right Parietal_Inf and the left SupraMarginal (r = -0.583, p = 0.001), and the left SupraMarginal and the right SupraMarginal (r = -0.377, p = 0.048).

CONCLUSION

Plasma levels of Cr, Cu, Tl, Cs, and Sb were associated with altered rs-FC in brain regions related to motor control, sensory integration, executive function, language processing, and emotional regulation in ischemic stroke patients with basal ganglia infarction.

Association of Blood Copper With the Subclinical Carotid Atherosclerosis: An Observational Study

BACKGROUND

Copper exposure is reported to be associated with increased risk of stroke. However, the association of copper exposure with subclinical carotid atherosclerosis remains unclear.

METHODS AND RESULTS

This observational study included consecutive participants from Xinqiao Hospital between May 2020 and August 2021. Blood metals were measured using inductively coupled plasma mass spectrometry and carotid atherosclerosis was assessed using ultrasound. Modified Poisson regression was performed to evaluate the associations of copper and other metals with subclinical carotid plaque presence. Blood metals were analyzed as categorical according to the quartiles. Multivariable models were adjusted for age, sex, body mass index, education, smoking, drinking, hypertension, diabetes, dyslipidemia, estimated glomerular filtration rate, and coronary artery disease history. Bayesian Kernel Machine Regression was conducted to evaluate the overall association of metal mixture with subclinical carotid plaque presence. One thousand five hundred eighty-five participants were finally enrolled in our study, and carotid plaque was found in 1091 subjects. After adjusting for potential confounders, metal-progressively-adjusted models showed that blood copper was positively associated with subclinical carotid plaque (relative risk according to comparing quartile 4 to quartile 1 was 1.124 [1.021-1.238], relative risk according to per interquartile increment was 1.039 [1.008-1.071]). Blood cadmium and lead were also significantly associated with subclinical carotid plaque. Bayesian Kernel Machine Regression analyses suggested a synergistic effect of copper-cadmium-lead mixture on subclinical carotid plaque presence.

CONCLUSIONS

Our findings identify copper as a novel risk factor of subclinical carotid atherosclerosis and show the potential synergistic proatherogenic effect of copper, cadmium, and lead mixture.

The Role of Astrocytic Mitochondria in the Pathogenesis of Brain Ischemia

The morbidity rate of ischemic stroke is increasing annually with the growing aging population in China. Astrocytes are ubiquitous glial cells in the brain and play a crucial role in supporting neuronal function and metabolism. Increasing evidence shows that the impairment or loss of astrocytes contributes to neuronal dysfunction during cerebral ischemic injury. The mitochondrion is increasingly recognized as a key player in regulating astrocyte function. Changes in astrocytic mitochondrial function appear to be closely linked to the homeostasis imbalance defects in glutamate metabolism, Ca2+ regulation, fatty acid metabolism, reactive oxygen species, inflammation, and copper regulation. Here, we discuss the role of astrocytic mitochondria in the pathogenesis of brain ischemic injury and their potential as a therapeutic target.

Cuproptosis in stroke: focusing on pathogenesis and treatment

Annually, more than 15 million people worldwide suffer from stroke, a condition linked to high mortality and disability rates. This disease significantly affects daily life, impairing everyday functioning, executive function, and cognition. Moreover, stroke severely restricts patients' ability to perform daily activities, diminishing their overall quality of life. Recent scientific studies have identified cuproptosis, a newly discovered form of cell death, as a key factor in stroke development. However, the role of cuproptosis in stroke remains unclear to researchers. Therefore, it is crucial to investigate the mechanisms of cuproptosis in stroke's pathogenesis. This review examines the physiological role of copper, the characteristics and mechanisms of cuproptosis, the differences and similarities between cuproptosis and other cell death types, and the pathophysiology of cuproptosis in stroke, focusing on mitochondrial dysfunction and immune infiltration. Further research is necessary to understand the relationship between previous strokes and cuproptosis and to clarify the mechanisms behind these associations.

Circulating copper levels and the risk of cardio-cerebrovascular diseases and cardiovascular and all-cause mortality: A systematic review and meta-analysis of longitudinal studies

BACKGROUND

Copper is an essential trace element in the human body; its relationship with cardio-cerebrovascular diseases (CCVDs) remains unclear. This study aimed to comprehensively investigate the association between circulating copper concentrations and CCVD risk and mortality.

METHODS

We searched the PubMed, Cochrane Library, Embase, Scopus, and Web of Knowledge databases for cohort studies reporting associations between circulating copper concentrations and cardiovascular diseases and mortality published up to August 23, 2023. Effect sizes were pooled using random-effects models. We graded the certainty of the evidence by the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework.

RESULTS

Our analysis included 47,813 patients across 17 cohort studies. Elevated circulating copper levels were linked to the risk of stroke (OR = 1.52; 95% CI 1.30-1.78), coronary artery disease mortality (RR = 2.77; 95% CI 1.82-4.19), cardiovascular mortality (RR = 1.79; 95% CI 1.52-2.11), and all-cause mortality (RR = 1.56; 95% CI 1.35-1.79) but not the risk of acute myocardial infarction (RR = 2.01; 95% CI 0.63-6.47). Continuous analysis (per 20 μg/dl increase) showed consistent results regarding the association between copper levels and stroke incidence (OR = 1.23; 95% CI 1.14-1.33), cardiovascular mortality (HR = 1.28; 95% CI 1.07-1.53) and all-cause mortality (HR = 1.22; 95% CI 1.04-1.44). Except for the low certainty of evidence of acute myocardial infarction incidence, all outcomes had moderate certainty of evidence.

CONCLUSION

Excessive circulating copper levels are associated with stroke, coronary artery disease mortality, cardiovascular mortality, and all-cause mortality with moderate certainty.

Association between serum copper levels and stroke in the general population: A nationally representative study

OBJECTIVES

The objective was to explore the association between serum copper levels and the prevalence of stroke.

METHODS

Data were obtained from 3 consecutive National Health and Nutrition Examination Survey (NHANES) cycles (2011-2016). Weighted multivariable logistic regression analysis was conducted to evaluate the association between serum copper levels and self-reported stroke.

RESULTS

A total of 5,151 adults met the inclusion criteria. A total of 181 (3.51%) stroke patients were identified. In comparison to individuals with serum copper levels in the lowest tertile (<16.4 µmol/l), those with levels in the middle tertile (16.4-19.8 µmol/l) had an odds ratio (OR) of 0.99 (95% confidence interval [CI]: 0.44-2.25), while those with levels in the highest tertile (>19.8 µmol/l) had an OR of 2.36 (95% CI: 1.01-5.52). Furthermore, each standard deviation (SD) increase in serum copper was found to be positively associated with the prevalence of stroke, with an OR of 1.44 (95% CI: 1.11-1.86). Dose‒response analysis showed a positive linear association between serum copper levels and stroke (Pnonlinearity=0.554).

CONCLUSIONS

This cross-sectional study suggested a positive association between serum copper levels and stroke among American adults.

Poor sleep quality association with higher lung cancer risk: a nested case-control study

Background

Little is known about the relationship between sleep quality and lung cancer incidence. Thus, this study was conducted to investigate the potential connection between sleep quality and lung cancer incidence.

Methods

We performed and selected a nested case-control study that included 150 lung cancer cases and 150 matched controls based on the Lianyungang cohort. Univariate and multivariate logistic regression was utilized to investigate the connection between potential risk factors and lung cancer incidence risk.

Results

In this study, the average age of participants was 66.5 ± 9.1 years, with 58.7% being male, and 52.7% reportedly experiencing sleep quality problems. The results of multivariate logistic regression showed that poor sleep quality was connected to an increased lung cancer incidence risk (P = 0.033, odds ratio = 1.83, 95% confidence interval = [1.05-3.19]) compared with those with good sleep quality. The stratified analyses showed a significantly positive connection between poor sleep quality (vs. good sleep quality) and cancer risk in smokers (vs. non-smoker, P for interaction = 0.085). The combined effect analysis indicated that smokers with poor sleep quality suffered from a 2.79-fold increase in cancer incidence rates when compared with non-smokers with good sleep quality.

Conclusions

Poor sleep quality was positively connected to an increased lung cancer incidence risk. In addition, among those individuals with poor sleep quality, smoking increased the lung cancer incidence risk.

Association between serum copper levels and risk of cardiovascular disease: A nested case-control study in the PREDIMED trial

BACKGROUND AND AIM

Certain trace elements have been associated with increased cardiovascular risk. The aim of this study was to evaluate the association between serum copper (S-Cu) levels and the risk of a first event of cardiovascular disease (CVD) in a population of older adults with high cardiovascular risk.

METHODS AND RESULTS

We conducted a case-control study nested within the PREDIMED trial. During a median follow-up of 4.8 years, a total of 207 incident cases diagnosed with CVD were matched for sex, age, and intervention group with 436 controls. Personal interviews, reviews of medical records, and validated questionnaires were used to assess known CVD risk factors. Biological serum samples were collected annually. Inductively coupled plasma mass spectrometry analysis was used to determine S-Cu levels. Adjusted odds ratios were calculated using multivariate conditional logistic regression models. All participants had S-Cu levels within the reference values, 750 μg/L to 1450 μg/L. Among men, but not among women, the mean S-Cu concentration was higher in cases 1014.1 μg/L than in controls 959.3 μg/L; (p = 0.004). In men, the multivariable-adjusted odds ratio for CVD was 2.36 (95% CI 1.07-5.20 for the comparison of the highest vs. the lowest quartile; p for trend = 0.02), in women, it was 0.43 (95% CI 0.11-1.70; p for trend = 0.165).

CONCLUSION

In older Spanish men with high cardiovascular risk, a significant association was observed between high S-Cu levels, but still within the reference values, and an increased risk of a first event of CVD. Our findings suggest a sex difference in CVD risk and S-Cu levels. To confirm this relationship and to analyze the differences observed between men and women, further studies are needed.

Association of serum copper (Cu) with cardiovascular mortality and all-cause mortality in a general population: a prospective cohort study

BACKGROUND

Copper (Cu) homeostasis and Cu-induced cell death are gaining recognition as crucial processes in the pathogenesis of cardiovascular disease (CVD). Circulating Cu associated with CVD and mortality is yet to be fully elucidated.

OBJECTIVE

This national prospective cohort study is to estimate relationship between serum Cu and the risk of CVD and all-cause mortality.

METHODS

This study included participants from the National Health and Nutrition Examination Survey 2011-2016. Weighted Cox proportional hazards regression analysis and exposure-response curves were applied.

RESULTS

This included 5,412 adults, representing 76,479,702 individuals. During a mean of 5.85 years of follow-up (31,653 person-years), 96 CVD and 356 all-cause mortality events occurred. Age and sex-adjusted survival curves showed that individuals with higher levels of serum Cu experienced increased CVD and all-cause death rates (tertiles, p < 0.05). Compared with the participant in tertile 1 of serum Cu (< 16.31 mol/L), those in tertile 3 (≥ 19.84 mol/L) were significantly associated with CVD mortality (HR: 7.06, 95%CI: 1.85,26.96), and all-cause mortality (HR: 2.84, 95% CI: 1.66,4.87). The dose-response curve indicated a linear relationship between serum Cu and CVD mortality (p -nonlinear = 0.48) and all-cause (p -nonlinear = 0.62). A meta-analysis included additional three prospective cohorts with 13,189 patients confirmed the association between higher serum Cu and CVD (HR: 2.08, 95% CI: 1.63,2.65) and all-cause mortality (HR: 1.89, 95%CI: 1.58,2.25).

CONCLUSION

The present study suggests excessive serum Cu concentrations are associated with the risk of CVD and all-cause mortality in American adults. Our findings and the causal relationships require further investigation.

Serum copper levels and risk of major adverse cardiovascular events: a systematic review and meta-analysis

Background

Despite the fact that several studies have investigated the association between serum copper levels (S-Cu) and the risk of cardiovascular diseases, this relationship remains unclear. The aims of this study were to investigate the association between S-Cu and risk of major adverse cardiovascular events (MACE), including total stroke, ischemic stroke, hemorrhagic stroke, myocardial infarction and cardiovascular mortality, and identify potential sources of results heterogeneity.

Methods

We carried out a systematic review and meta-analysis. The selection criteria were: (1) Observational studies (cohort studies, case-control studies and hybrid studies); (2) Studies containing quantitative data about the relationship between S-Cu and risk of MACE; (3) Estimating association measures; and (4) Studies written in English, French or Spanish. Overall pooled Odds ratio (pOR) and 95% confidence intervals (95% CI) of MACE for the highest vs. lowest S-Cu category were calculated using random-effects models.

Results

Sixteen studies with a total of 41,322 participants were included in the meta-analysis: 10 prospective cohort studies, 5 nested case-control studies and 1 case-control study. Comparing highest vs. lowest category, high S-Cu levels were associated with total stroke (pOR: 1.49, 95% CI 1.22-1.82; I² = 0%, p = 0.54), myocardial infarction (pOR: 1.31, 95% CI 1.17-1.46; I² = 0.0%, p = 0.92) and cardiovascular mortality (pOR: 1.60, 95% CI 1.39-1.86; I² = 0.0%, p = 0.54). Subgroup analysis showed that studies with a hybrid design had higher risks for cardiovascular mortality (pOR: 3.42, 95% CI 1.98-5.92) and ischemic stroke (pOR: 1.54, 95% CI 1.30-1.83).

Conclusion

High S-Cu levels were associated with an increased risk of total stroke, myocardial infarction and cardiovascular mortality. Hybrid studies seems to modify the strength of the association between S-Cu and the risk of cardiovascular mortality and ischemic stroke.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022370782], identifier [CRD42022370782].

Association between plasma selenium and risk of ischemic stroke: A community-based, nested, and case-control study

Background

The prospective association between plasma Se and stroke risk remains inconclusive. The relationship between Se and ischemic stroke among a low circulating Se status population deserves more attention, especially for Chinese people who were a high-risk group for Se deficiency.

Objective

The relationship between plasma Se concentration and ischemic stroke risk in a large-scale Chinese community-based population and any potential effect modifiers were investigated.

Methods

A nested, case-control study, using data from the “China H-type Hypertension Registry Study” were conducted. A total of 1,904 first ischemic stroke cases and 1,904 controls matched for age, sex, and village were included in this study. The association between plasma Se and first ischemic stroke was evaluated by conditional logistic regression analyses.

Results

The median value of plasma Se was 65.8 μg/L among total participants. Overall, a significant inverse relationship between plasma Se and first ischemic stroke risk was found (per SD increment; adjusted OR: 0.87; 95% CI: 0.80 and 0.95). Accordingly, a significantly lower risk of first ischemic stroke was found in participants in quartile 3 (65.8−&lt;77.8 μg/L) (adjusted OR: 0.78; 95% CI: 0.63 and 0.96) and quartile 4 (≥77.8 μg/L) (adjusted OR: 0.76; 95% CI: 0.59 and 0.96), compared with those in quartile 1 (&lt;56.0 μg/L). Furthermore, a significantly lower ischemic stroke risk was found in those with lower low-density lipoprotein cholesterol (LDL-C) levels (&lt;3.4 vs. ≥3.4 mmol/L; P for interaction = 0.015) or those with lower homocysteine levels (&lt;12.1 (median) vs. ≥12.1 μmol/L; P for interaction = 0.027) at baseline.

Conclusion

Plasma Se was significantly inversely associated with the risk of first ischemic stroke among a large-scale Chinese community-based population (most adults with hypertension and elevated total homocysteine), especially among those with lower LDL-C and lower homocysteine levels.

The Role of Copper Homeostasis in Brain Disease

In the human body, copper is an important trace element and is a cofactor for several important enzymes involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis, and neurotransmitter synthesis. Copper is also necessary for cellular processes, such as the regulation of intracellular signal transduction, catecholamine balance, myelination of neurons, and efficient synaptic transmission in the central nervous system. Copper is naturally present in some foods and is available as a dietary supplement. Only small amounts of copper are typically stored in the body and a large amount of copper is excreted through bile and urine. Given the critical role of copper in a breadth of cellular processes, local concentrations of copper and the cellular distribution of copper transporter proteins in the brain are important to maintain the steady state of the internal environment. The dysfunction of copper metabolism or regulatory pathways results in an imbalance in copper homeostasis in the brain, which can lead to a myriad of acute and chronic pathological effects on neurological function. It suggests a unique mechanism linking copper homeostasis and neuronal activation within the central nervous system. This article explores the relationship between impaired copper homeostasis and neuropathophysiological progress in brain diseases.

Association between serum calcium levels and first stroke: A community-based nested case-control study

Background

Evidence from epidemiologic studies has been limited and inconsistent regarding the role of serum calcium in stroke incidence risk. We aimed to evaluate the association between serum albumin-corrected calcium and the risk of the first stroke in the Chinese community-dwelling population.

Methods

The study sample population was drawn from the “H-type Hypertension and Stroke Prevention and Control Project.” Using a nested case-control study, a total of 1,255 first-stroke cases and 1,255 controls matched for age, sex, and village were included in the final data analysis. We measured the serum calcium by inductively coupled plasma mass spectrometry and assessed the associations between serum albumin-corrected calcium and first stroke using conditional logistic regression.

Results

The overall mean (SD) serum albumin-corrected calcium was 8.9 (0.6) mg/dl. Compared with the middle tertile (8.7–9.1 mg/dl), the multivariate-adjusted odds ratios (95% CIs) of first total stroke associated with the lowest tertile and the highest tertile of serum albumin-corrected calcium were 1.37 (1.10, 1.70) and 1.30 (1.04, 1.62), respectively. Similar trends were observed for the first ischemic stroke. Consistently, restricted cubic spline showed a U-shaped association between serum albumin-corrected calcium and risk of total stroke and ischemic stroke. However, serum albumin-corrected calcium had no significant effect on first hemorrhagic stroke. No significant effect modification was observed in the subgroup analysis.

Conclusions

Our results suggested a U-shaped association between serum calcium and first stroke; both low and high serum calcium levels were associated with an increased risk of the first stroke in the Chinese population.

Crosstalk of copper and zinc in the pathogenesis of vascular dementia

Copper and zinc are essential for normal brain functions. Both are localized in presynaptic vesicles and are secreted into synaptic clefts during neuronal excitation. Despite their significance, excesses of copper and zinc are neurotoxic. In particular, excess zinc after transient global ischemia plays a central role in the ischemia-induced neurodegeneration and pathogenesis of vascular type senile dementia. We previously found that sub-lethal concentrations of copper remarkably exacerbated zinc-induced neurotoxicity, and we investigated the molecular pathways of copper-enhanced zinc-induced neurotoxicity. The endoplasmic reticulum stress pathway, the stress-activated protein kinases/c-‍Jun amino-terminal kinases pathway, and mitochondrial energy production failure were revealed to be involved in the neurodegenerative processes. Regarding the upstream factors of these pathways, we focused on copper-derived reactive oxygen species and the disruption of calcium homeostasis. Because excess copper and zinc may be present in the synaptic clefts during ischemia, it is possible that secreted copper and copper-induced reactive oxygen species may enhance zinc neurotoxicity and eventually contribute to the pathogenesis of vascular type senile dementia.

Novel Insights on Establishing Machine Learning-Based Stroke Prediction Models Among Hypertensive Adults

Background

Stroke is a major global health burden, and risk prediction is essential for the primary prevention of stroke. However, uncertainty remains about the optimal prediction model for analyzing stroke risk. In this study, we aim to determine the most effective stroke prediction method in a Chinese hypertensive population using machine learning and establish a general methodological pipeline for future analysis.

Methods

The training set included 70% of data (n = 14,491) from the China Stroke Primary Prevention Trial (CSPPT). Internal validation was processed with the rest 30% of CSPPT data (n = 6,211), and external validation was conducted using a nested case–control (NCC) dataset (n = 2,568). The primary outcome was the first stroke. Four received analysis methods were processed and compared: logistic regression (LR), stepwise logistic regression (SLR), extreme gradient boosting (XGBoost), and random forest (RF). Population characteristic data with inclusion and exclusion of laboratory variables were separately analyzed. Accuracy, sensitivity, specificity, kappa, and area under receiver operating characteristic curves (AUCs) were used to make model assessments with AUCs the top concern. Data balancing techniques, including random under-sampling (RUS) and synthetic minority over-sampling technique (SMOTE), were applied to process this unbalanced training set.

Results

The best model performance was observed in RUS-applied RF model with laboratory variables. Compared with null models (sensitivity = 0, specificity = 100, and mean AUCs = 0.643), data balancing techniques improved overall performance with RUS, demonstrating a more satisfactory effect in the current study (RUS: sensitivity = 63.9; specificity = 53.7; and mean AUCs = 0.624. Adding laboratory variables improved the performance of analysis methods. All results were reconfirmed in validation sets. The top 10 important variables were determined by the analysis method with the best performance.

Conclusion

Among the tested methods, the most effective stroke prediction model in targeted population is RUS-applied RF. From the insights, the current study revealed, we provided general frameworks for building machine learning-based prediction models.

Environmental toxic metal contaminants and risk of stroke: a systematic review and meta-analysis

The relationship between toxic metals in the environment and clinical stroke risk remains unclear, although their role as immunotoxicants and carcinogens has been well established. We conducted a systematic review of the relationship between five metals (arsenic, mercury, copper, cadmium, and lead) and stroke. First, we comprehensively searched 3 databases (Pubmed, EMBASE, and Cochrane) from inception until June 2021. Random-effects meta-analyses, pooled relative risks (RR) and 95% confidence intervals (CI) were applied to evaluate the effect value. We finally identified 38 studies involving 642,014 non-overlapping participants. Comparing the highest vs. lowest baseline levels, chronic exposure to lead (RR = 1.07; 95%CI,1.00-1.14), cadmium (RR = 1.30; 95%CI,1.13-1.48), and copper (RR = 1.19; 95%CI,1.04-1.36) were significantly associated with stroke risks. However, the other two metals (arsenic and mercury) had less effect on stroke risk. Further analysis indicated that the association was likely in a metal dose-dependent manner. The results may further support the possibility that environmental toxic metal contaminants in recent years are associated with the increased risk of stroke.

The Relative Contribution of Plasma Homocysteine Levels vs. Traditional Risk Factors to the First Stroke: A Nested Case-Control Study in Rural China

Background

Approximately 75% of Chinese hypertensive patients have elevated homocysteine (Hcy). Its implication in risk assessment and prevention of the first stroke remains an important clinical and public health question.

Methods

This study was based on a community cohort recruited from 2016 to 2018 in the rural China. To maximize cost efficiency, we used a nested case-control design, including 3,533 first stroke cases and 3,533 controls matched for age ±1 years, sex, and village. Individual associations of tHcy and traditional risk factors with the first stroke were examined, and their population-attributable risks (PARs) were estimated.

Results

There was a significant dose-response association between first stroke and total Hcy (tHcy) levels, with adjusted odds ratios of 1.11 (95% CI: 0.97, 1.26) for tHcy 10–15 μmol/L and 1.44 (1.22, 1.69) for tHcy ≥ 15 μmol/L, all compared to tHcy &lt; 10 μmol/L. A similar trend was found for ischemic and hemorrhagic stroke. tHcy and systolic blood pressure (SBP) were independently and additively associated with the risk of first stroke (tHcy: 1.06 [1.02, 1.1]; SBP: 1.13 [1.1, 1.16]; P-interaction, 0.889). Among the ten main risk factors examined, the top two contributors to the first stroke were SBP and tHcy, with PARs of 25.73 and 11.24%, respectively.

Conclusions

Elevated tHcy is the second most important contributor and acts additively with SBP to increase the risk of the first stroke. This finding underscores the importance of screening and treating elevated tHcy along with traditional risk factors to further reduce the burden of the first stroke in the high-risk populations.

Dietary Copper Intake and Risk of Stroke in Adults: A Case-Control Study Based on National Health and Nutrition Examination Survey 2013-2018

The association between dietary copper intake and the risk of stroke is unknown. We included a total of 10,550 participants from the National Health and Nutrition Examination Survey (NHANES) 2013−2018. Two 24-h dietary recalls and a standard questionnaire were used to determine copper intake and stroke, respectively. We used logistic regression models to estimate the associations between dietary copper intake and the risk of stroke. The nearest-neighbor propensity score matching (PSM) with a ratio of 1:2 was used to reduce selection bias. The non-linear relationship was explored with restricted cubic splines (RCS). The correlation between copper intake and baseline characteristics was detected by the Pearson correlation coefficient. The median dietary copper intake was 1.072 mg/day (IQR = 1.42−0.799). Approximately 3.8% (399) of the participants had a history of stroke. A multivariate logistic regression analysis before and after matching showed that subjects in the higher quartile had significantly lower odds of stroke compared with subjects in the first quartile of copper intake. A stratified analysis showed that copper intake was a significant protective factor for women, individuals <65 years old, individuals with hypertension, individuals who smoke, and diabetic stroke patients. The RCS models showed an L-shaped nonlinear relationship (p for nonlinear < 0.001) between copper intake and stroke. Our results suggested that increased dietary copper intake was associated with a lower risk of stroke.

Copper as a Collaborative Partner of Zinc-Induced Neurotoxicity in the Pathogenesis of Vascular Dementia

Copper is an essential trace element and possesses critical roles in various brain functions. A considerable amount of copper accumulates in the synapse and is secreted in neuronal firings in a manner similar to zinc. Synaptic copper and zinc modulate neuronal transmission and contribute to information processing. It has been established that excess zinc secreted during transient global ischemia plays central roles in ischemia-induced neuronal death and the pathogenesis of vascular dementia. We found that a low concentration of copper exacerbates zinc-induced neurotoxicity, and we have demonstrated the involvement of the endoplasmic reticulum (ER) stress pathway, the stress-activated protein kinases/c-Jun amino-terminal kinases (SAPK/JNK) signaling pathway, and copper-induced reactive oxygen species (ROS) production. On the basis of our results and other studies, we discuss the collaborative roles of copper in zinc-induced neurotoxicity in the synapse and the contribution of copper to the pathogenesis of vascular dementia.

Association of Brachial Ankle Pulse Wave Velocity With New Onset Stroke in Hypertensive Patients Aged Less Than 65 With Normal Fasting Glucose Among Chinese Community-Based Population

BACKGROUND

Previous studies have shown an association of stroke and brachial ankle pulse wave velocity (baPWV). However, due to limitations on total population size and small numbers of stroke cases, lack of power has prevented further detection among subgroups such as age and laboratory testing.

METHODS

A total of 19217 participants including 660 incident stroke patients were pooled in the present study. Participants were divided to 2 groups, aged less than 65 years [56.0 (50.0, 61.0)] and aged 65 years or more [70.0 (67.0, 74.0)].

RESULTS

After adjustment for demographic, anthropometric, and laboratory parameters, the incident stroke was positively associated to baPWV in the group aged less than 65 years (OR, 1.16; 95% CI, 1.05-1.28), but not in the older group aged 65 or more. When baPWV was assigned as quartiles, a significant, increased risk of new-onset stroke was found in quartiles 3-4 compared with quartile 1. In addition, the predictive value of baPWV for incident stroke was modified by fasting glucose in participants aged less than 65 years (P-interaction = 0.010). An increase in baPWV was strongly, positively associated to new-onset stroke in the subgroup of normal fasting glucose (< 5.6 mmol/L) (OR, 1.34; 95% CI, 1.15 - 1.57), but no effect was seen in the impaired fasting glucose (5.6-7.0 mmol/L) or diabetic fasting glucose (> 7.0 mmol/L) subgroups.

CONCLUSIONS

Increased baPWV was significantly associated with new-onset stroke in a hypertensive population aged less than 65 years. Particularly, it is of great importance to monitor baPWV for predicting incident stroke in "relatively healthy" hypertensive patients, i.e. aged less than 65 years with normal fasting glucose.