High-molecular-weight adiponectin and incident ischemic stroke in postmenopausal women: a Women's Health Initiative Study

Cardiovascular risk factors and breast cancer incidence in a large middle-aged cohort study

BACKGROUND

Several studies have demonstrated that cardiovascular risk factors play a role in the etiology of breast cancer. However, the combined effect of cardiovascular risk factors on the risk of breast cancer is still uncertain.

METHODS

Data from the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort of middle-aged women, were used to investigate the association of individual and combined cardiovascular risk factors with breast cancer. Cox proportional hazards models were applied to calculate the hazard ratio (HR) and 95% confidence intervals (CI).

RESULTS

A total of 7501 women were included. During a mean follow-up of 19.7 years, 576 women were diagnosed with breast cancer. White women and premenopausal status were independently associated with increased risk of breast cancer. Of the individual cardiovascular risk factors, only obesity was independently associated with an increased risk of breast cancer (HR 1.29, 95% CI 1.04-1.61). Compared with women without cardiovascular risk factors, women having three or greater, but not those with fewer than three cardiovascular risk factors, had a significantly higher risk of developing breast cancer (HR 1.27, 95% CI 1.06-1.53). Subgroup analyses indicated that women with three or greater cardiovascular risk factors had higher risk of breast cancer among postmenopausal Black women, but not among premenopausal Black and White women.

CONCLUSIONS

Combinations of cardiovascular risk factors are associated with increased risk of breast cancer in middle-aged women, especially in postmenopausal Black women. Joint interventions to modify cardiovascular risk factors could be used to prevent breast cancer in these higher-risk individuals.

Relationship between adiponectin multimer levels and subtypes of cerebral infarction

Aim

Serum adiponectin levels are decreased in patients with cerebral infarction. Adiponectin in circulation exists in three isoforms: high molecular weight (HMW), medium molecular weight (MMW), and low molecular weight (LMW) adiponectin. We measured serum levels of total adiponectin and adiponectin multimers (HMW, MMW, and LMW) in patients with cerebral infarction and compared the serum levels of the three adiponectin multimers in stroke subtypes. We also evaluated the clinical value of adiponectin multimer levels as a biomarker for cerebral infarction.

Methods

We assessed a total of 132 patients with cerebral infarctions. The serum levels of total and adiponectin multimers were measured using enzyme-linked immunosorbent assay (ELISA).

Results

The total and HMW adiponectin levels were significantly lower in atherothrombotic infarction (AI) than in cerebral embolism (CE) (total, p < 0.05; HMW, p < 0.05). In male patients, the MMW adiponectin level was significantly lower in the lacunar infarction (LI) group than in the AI group (p < 0.05). The LMW adiponectin level was significantly lower in the AI group than in the LI and CE groups (LI, p < 0.001; CE, p = 0.001). However, there were no significant differences in adiponectin multimer levels among the stroke subtypes in female subjects. Additionally, in female patients with AI and LI, the LMW adiponectin levels were negatively associated with C-reactive protein (CRP; AI, p < 0.05; LI, p < 0.05).

Conclusion

These findings suggest that a decrease in adiponectin is associated with AI and that serum LMW adiponectin level represents a potential biomarker for AI.

[Epicardial and subcutenious adipose tissue adiponectin gene expression in coronary artery disease patients]

Aim To determine the expression of adiponectin gene (ADIPOQ) and the content of high-molecular-weight adiponectin (HMWA) in epicardial (EAT) and subcutaneous adipose tissue (SCAT) in patients with ischemic heart disease (IHD).Material and methods Paired samples of EAT and SCAT and blood serum were withdrawn from patients with IHD after bypass surgery and 16 subjects without IHD (comparison group). Matrix RNA (mRNA) level was measured using real-time polymerase chain reaction. HMWA levels in EAT and SCAT were evaluated by Western blotting. Serum adiponectin concentration was measured immunoenzymatically. For all patients, echocardiography was performed to measure the EAT thickness; coronarography was performed to determine severity of coronary atherosclerosis.Results Serum adiponectin concentration was lower in IHD patients than in the comparison group (p&lt;0.001). Levels of ADIPOO gene mRNA and HMWA in SCAT were lower in IHD patients than in the comparison group (р=0.020 and p=0.003, respectively). The HMWA level in EAT was lower with the EAT thickness of 8 mm compared to the HMWA level in IHD patients with EAT ≤8 mm (p=0.034).Conclusion The decreased serum concentration of antiatherogenic adiponectin and the reduced expression of ADIPOQ gene in SCAT (mRNA, HMWA) are associated with IHD.

Low bone mass is associated with carotid calcification plaque in Chinese postmenopausal women: the Chongqing osteoporosis study

Background: The aim of this study was to examine the relationship between low bone mass and the risk of carotid calcification plaques in Chinese postmenopausal women.Methods: We conducted a 5 years prospective study. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry (DXA) scanning. Carotid computed tomography angiography (CTA) was conducted using a 64-multidetector row scanner to assess carotid arterial plaque at baseline and during follow-up. Cox proportional hazards analysis was used to evaluate the association of BMD and risk of carotid calcification plaques.Results: Four hundred and eighty-eight women sustained prospective carotid plaques during the follow-up. Women with carotid calcification plaques had low BMD than those with carotid non-calcification plaques. After adjustment for potential confounders, BMD, age, years since menopause, levels of plasma osteoprotegerin and adiponectin, hypertension, diabetes mellitus and hyperlipidemia were independently associated with increased risk of carotid calcification plaques. For carotid calcification plaques, a significant inverse correlation was indicated between BMD and the plaques, and a significant positive correlation was indicated between bone loss and plaques.Conclusions: This study suggested that lower BMD and increased loss rate of BMD were associated with a higher risk of carotid calcification plaques in Chinese postmenopausal women.

Ischemic stroke and select adipose-derived and sex hormones: a review

Ischemic stroke is the fifth leading cause of death in the USA and is the leading cause of serious, long-term disability worldwide. The principle sex hormones (estrogen, progesterone, and testosterone), both endogenous and exogenous, have profound effects on various stroke outcomes and have become the focus of a number of studies evaluating risk factors and treatment options for ischemic stroke. In addition, the expression of other hormones that may influence stroke outcome, including select adipose-derived hormones (adiponectin, leptin, and ghrelin), can be regulated by sex hormones and are also the focus of several ischemic stroke studies. This review aims to summarize some of the preclinical and clinical studies investigating the principle sex hormones, as well as select adipose-derived hormones, as risk factors or potential treatments for ischemic stroke. In addition, the potential for relaxin, a lesser studied sex hormone, as a novel treatment option for ischemic stroke is explored.

Adipokines in neurovascular diseases

Adipose tissue is now described as an endocrine organ secreting a number of adipokines contributing to the development of inflammation and metabolic imbalance, but also endothelial dysfunction, vascular remodeling, atherosclerosis, and ischemic stroke. Leptin, adiponectin, and resistin are the most studied adipokines which play important roles in the regulation of cardiovascular homeostasis. Leptin and adiponectin mediate both proatherogenic and antiatherogenic responses. Leptin and adiponectin have been linked to the development of coronary heart disease and may be involved in the underlying biological mechanism of ischemic stroke. Resistin, a pro-inflammatory cytokine, is predictive of atherosclerosis and poor clinical outcomes in patients with coronary artery disease and ischemic stroke. The changes in serum levels of novel adipokines apelin, visfatin are also associated with acute ischemic stroke. These adipokines have been proposed as potential prognostic biomarkers of cardiovascular mortality/morbidity and therapeutic targets in patients with cardiometabolic diseases. In this article, we summarize the biologic role of the adipokines and discuss the link between dysfunctional adipose tissue and metabolic/inflammation imbalance, consequently endothelial damage, progression of atherosclerotic disease, and the occurrence of ischemic stroke.

Adiponectin circulating levels and 10-year (2002-2012) cardiovascular disease incidence: the ATTICA Study

PURPOSE

Adiponectin is an adipokine with anti-inflammatory and cardiovascular-protective properties. Existing epidemiological evidence is conflicting on the exact relationship between adiponectin and long-term cardiovascular disease (CVD) risk. Our aim was to prospectively assess whether circulating adiponectin is associated with long-term incident CVD.

METHODS

A population-based, prospective study in adults (>18 years) without previous CVD history (ATTICA study). Circulating total adiponectin levels were measured at baseline (2001-2002) in a sub-sample (n = 531; women/men: 222/309; age: 40 ± 11 years) of the ATTICA cohort and complete 10-year follow-up data were available in 366 of these participants (women/men: 154/212; age: 40 ± 12 years).

RESULTS

After adjusting for multiple factors, including age, sex, body mass index, waist circumference, smoking, physical activity, Mediterranean diet adherence, hypertension, diabetes, and hypercholesterolemia, our logistic regression analysis indicates that an increase in circulating total adiponectin levels by 1 unit was associated with 36% lower CVD risk (relative risk [RR]: 0.64, 95% confidence interval [CI] 0.42-0.96; p = 0.03). Further adjusting for interleukin-6 plasma levels had no significant impact (RR: 0.60, 95% CI 0.38-0.94; p = 0.03), while additional adjustment for circulating C-reactive protein (CRP) modestly attenuated this association (RR: 0.63, 95% CI 0.40-0.99; p = 0.046).

CONCLUSIONS

In our study, elevated circulating total adiponectin levels were associated with lower 10-year CVD risk in adults without previous CVD, independently of other established CVD risk factors. This association appeared to be modestly attenuated by CRP, yet was not mediated by interleukin-6 which is the main endocrine/circulating pro-inflammatory cytokine.

Circulating adiponectin levels in relation to carotid atherosclerotic plaque presence, ischemic stroke risk, and mortality: A systematic review and meta-analyses

BACKGROUND

Low circulating levels of adiponectin, an anti-inflammatory and vasculoprotective adipokine, are associated with obesity, type 2 diabetes, and atherosclerotic disease. Presence of unstable plaques in the carotid artery is a known etiological factor causing ischemic strokes. Herein, we systematically reviewed the association between circulating adiponectin and progression of carotid atherosclerotic disease, particularly evaluating the occurrence of (1) carotid atherosclerotic plaques, (2) ischemic stroke, and (3) mortality in subjects who suffered a previous ischemic stroke.

METHODS

Medline, Embase, Biosis, Scopus, Web of Science, and Pubmed were searched for published studies and conference abstracts. The effect size and 95% confidence intervals (CIs) of the individual studies were pooled using fixed-effect or random-effect models. The quality of the eligible studies was evaluated using the Newcastle-Ottawa quality assessment scale. Sensitivity, subgroup, and meta-regression analyses were performed to address the impact of various risk factors on the association between adiponectin and ischemic stroke risk.

RESULTS

Twelve studies fulfilled the inclusion criteria for 3 independent meta-analyses. The association of increasing circulating adiponectin levels (5μg/mL-increment) with presence of carotid plaque was not conclusive (n=327; OR: 1.07; 95% CI: 0.85-1.35; 2 studies), whereas high adiponectin levels showed a significant 8% increase in risk of ischemic stroke (n=13,683; 7 studies), with a more sizable association observed among men compared to women. HDL was observed to have a marginal effect on the association between adiponectin and ischemic stroke, while other evaluated parameters were not found to be effect modifiers. A non-significant association of adiponectin with mortality was yielded (n=663; OR: 2.58; 95% CI: 0.69-9.62; 3 studies). Although no publication bias was evident, there was significant between-study heterogeneity in most analyses.

CONCLUSION

It appears that the direction of the relationship between adiponectin and carotid atherosclerotic plaque presence is dependent on the duration, severity, and nature of the underlying disease, while increased adiponectin levels were associated with an increase in risk for ischemic stroke. Lastly, the results from the mortality meta-analysis remain inconclusive. Future properly designed studies are necessary to further elucidate the role of adiponectin on atherosclerotic plaque development, and its related outcomes.

Cerebrovascular Disease: Consequences of Obesity-Induced Endothelial Dysfunction

Despite the well-known global impact of overweight and obesity in the incidence of cerebrovascular disease, many aspects of this association are still inconsistently defined. In this chapter we aim to present a critical review on the links between obesity and both ischemic and hemorrhagic stroke and discuss its influence on functional outcomes, survival, and current treatments to acute and chronic stroke. The role of cerebrovascular endothelial function and respective modulation is also described as well as its laboratory and clinical assessment. In this context, the major contributing mechanisms underlying obesity-induced cerebral endothelial function (adipokine secretion, insulin resistance, inflammation, and hypertension) are discussed. A special emphasis is given to the participation of adipokines in the pathophysiology of stroke, namely adiponectin, leptin, resistin, apelin, and visfatin.

Association of Adiponectin Polymorphism with Metabolic Syndrome Risk and Adiponectin Level with Stroke Risk: A Meta-Analysis

Many previous studies have provided evidence that the ADIPOQ +45T>G polymorphism (rs2241766) might cause metabolic syndrome (MS). As a cardiovascular manifestation of MS, the incidence of stroke is associated with adiponectin; however, the results remain controversial and inconsistent. Systematic searches of relevant studies published up to Dec 2014 and Jan 2016 on the ADIPOQ +45T>G polymorphism and the risk of MS and adiponectin levels and the risk of stroke, respectively, were conducted in MEDLINE and EMBASE. The odds ratio (OR) or risk ratio (RR) and their 95% confidence interval (95% CI) were extracted. Sixteen studies containing 4,113 MS cases and 3,637 healthy controls indicated a weak positive association between ADIPOQ +45 T>G and MS in the dominant genetic model (OR = 1.30, 95% CI = 1.03-1.65), which was also validated by stratified subgroup analyses. Twelve studies including 26,213 participants and 4,246 stroke cases indicated that 5 μg/ml increments in adiponectin level were not relevant to stroke risk (RR = 1.05, 95% CI = 1.00-1.10, P = 0.069). This study suggested a weak positive association of ADIPOQ +45T>G with MS and a strong association with metabolic-related disease. Additionally, adiponectin level was not a causal factor of increasing stroke risk.

The role of adipokines in ischemic stroke risk stratification

Background

Adiponectin, leptin, and resistin are the most well-studied adipokines and play important roles in the regulation of glucose metabolism, subclinical inflammation, and cardiovascular homeostasis. Accordingly, measurement of adipokine levels might be useful in cardiovascular risk stratification. Moreover, the study of single-nucleotide polymorphisms of genes that encode these adipokines might also represent a valuable predictive tool in cardiovascular disease prevention strategies.

Aims

To summarize the biologic role of the adipokines adiponectin, leptin, and resistin and the prognostic value of their serum levels regarding the occurrence and outcome of ischemic stroke. We also discuss the relationship of single-nucleotide polymorphisms of the adiponectin, leptin genes, and the −420C > G polymorphism of resistin gene with stroke risk.

Summary of review

Several studies in the general population evaluated the association between these adipokines and stroke risk, yielding conflicting results. There are more limited data regarding the effect of these adipokines on stroke severity and outcome. A small number of studies also assessed the predictive role of single-nucleotide polymorphisms of the adiponectin, leptin, and resistin genes regarding stroke risk, but the findings were also controversial.

Conclusions

It is unclear whether adiponectin, leptin, and resistin levels or the single-nucleotide polymorphisms of their encoding genes are independently associated with stroke risk. However, given the role of these adipokines in the pathogenesis of atherosclerosis, larger prospective studies, both in the general population and in patients with a history of stroke, are needed to determine whether the measurement of serum levels of these adipokines or the evaluation of single-nucleotide polymorphisms in their encoding genes could improve stroke risk prediction. If this relationship is proven, therapeutic interventions targeting adipokine levels might represent a novel approach to reduce stroke-related mortality and disability.

Lower levels of plasma adiponectin and endothelial progenitor cells are associated with large artery atherosclerotic stroke

BACKGROUND

Both adiponectin and endothelial progenitor cells (EPCs) have been proposed recently with anti-atherosclerosis effects. However, their impacts on vascular outcomes in patients with large artery atherosclerosis (LAA) are unclear. This study aimed to investigate the relationship between adiponectin, EPCs and stroke with a case-control design.

METHODS

The study cohort included 127 patients (61.3 ± 11.0 years; 73.2% men) with LAA stroke and 58 control subjects (60.9 ± 9.2 years; 70.7% men) referred for adiponectin and EPCs levels testing. We collected demographic, clinical, angiographical features, and laboratory data. Influence of adiponectin and EPCs levels on cerebral atherosclerosis and LAA stroke was analyzed with regression models.

RESULTS

The levels of adiponectin and EPCs in atherosclerotic stroke patients were significantly lower compared with matched controls (p < 0.05). Logistic regression analysis identified that reduced levels of adiponectin and EPCs were closely correlated with cerebral atherosclerosis and LAA stroke. The associations remained significant after adjustment for age, sex and other confounders. Additionally, partial correlation analysis revealed a significant positive association between adiponectin and three subpopulations of EPCs levels (CD34(+)CD133(+)CD309(+)cells: r = 0.510, p = 0.001; CD34(+) CD133(-)CD309(+)cells: r = 0.262, p = 0.004; CD34(-)CD133(+)CD309(+)cells: r = 0.348, p < 0.001).

CONCLUSIONS

Adiponectin is positively correlated with EPCs levels, and both of them are independently associated with LAA stroke.

The Intricate Network of Adipokines and Stroke

Cerebrovascular disorders, particularly ischemic stroke, are one of the most common neurological disorders. High rates of overweight and obesity support an interest in the role of adipose tissue and adipose tissue releasing cytokines in inducing associated comorbidities. Adipokines can serve as a key messenger to central energy homeostasis and metabolic homeostasis. They can contribute to the crosstalk between adipose tissue and brain. However recent research has offered ambiguous data on the network of adipose tissue, adipokines, and vascular disorders. In our paper we provide a critical insight into the role of adipokines in evolution of ischemic stroke.

Significance of plasma adiponectin for diagnosis, neurological severity and functional outcome in ischemic stroke - Research for Biomarkers in Ischemic Stroke (REBIOS)

OBJECTIVE

Although adiponectin is a major adipocytokine that affects the pathogenesis of various cardiovascular diseases, its clinical significance in stroke remains controversial. We investigated the clinical significance of plasma adiponectin for the diagnosis, neurological severity and functional outcomes of patients with ischemic stroke.

METHODS

We prospectively enrolled 171 patients with ischemic stroke and 171 age- and sex-matched healthy controls. Blood samples and clinical information were obtained at day 0, 3, 7, 14 and 90 after stroke onset.

RESULTS

Average adiponectin values at day 0 did not significantly differ between the controls and the patients, but were significantly lower and higher in patients with atherothrombotic brain (ATBI) (p=0.047) and cardioembolic (CE) (p=0.008) infarction, respectively, than in the controls. Multivariate logistic regression analyses showed that the adiponectin value at day 0 could predict ATBI (odds ratio, 0.75; 95% confidence interval, 0.58 to 0.91, p=0.009, per 1-μg/mL increase). Adiponectin values at day 0 were positively associated with neurological severity as evaluated by the National Institute of Health Stroke Scale upon admission (r=0.420, p=0.003) and were higher in the groups with poor outcomes (modified Rankin Scale (mRS) ≥ 3 on day 90) than in those with good ones (mRS ≤ 2) in all stroke subtypes, with statistical significance in ATBI (p=0.015).

CONCLUSIONS

Plasma adiponectin values may help to classify stroke subtypes and predict neurological severity and functional outcome in ischemic stroke patients.

Clinical use of adiponectin as a marker of metabolic dysregulation

Adiponectin concentrations exhibit strong cross-sectional relationships with obesity, inflammation, and diabetes. Adiponectin concentrations have been extensively evaluated as epidemiologic markers of diabetes and cardiovascular disease risk. In the present review we will provide an overview of these epidemiologic relationships as the backdrop for an evaluation of the clinical applications of adiponectin measurements. These include using adiponectin as an indicator of need for preventive or therapeutic intervention, as a predictor of response to therapy, and as a marker of therapeutic effectiveness. These efforts are laying the groundwork for the transition of adiponectin measurements from the laboratory to the clinic.

Adiponectin and risk of stroke: prospective study and meta-analysis

BACKGROUND AND PURPOSE

The favorable cardiovascular effects attributed to adiponectin may lower risk of stroke. We investigated this in a prospective study and meta-analysis.

METHODS

A case-cohort study nested within the Potsdam cohort of the European Prospective Investigation into Cancer was performed, with 170 incident cases of ischemic stroke and a randomly selected subcohort of 2155 participants without major cardiovascular disease at baseline. A random-effects dose-response meta-analysis was performed on prospective studies reporting on adiponectin and incident stroke in healthy populations up to April 2013, identified through MEDLINE and EMBASE.

RESULTS

In European Prospective Investigation into Cancer-Potsdam, after adjustment for cardiovascular risk factors, the hazard ratio of ischemic stroke per 5-µg/mL higher total-adiponectin was 1.10 (95% confidence interval, 0.89-1.37). Participants with higher total-adiponectin had higher high-density lipoprotein-cholesterol and lower high-sensitivity C-reactive protein and triglyceride levels, and had less often diabetes mellitus. Additional adjustment for these putative mediators yielded a hazard ratio of 1.31 (95% confidence interval, 1.04-1.64). Nine studies (19,259 participants, 2960 cases), including European Prospective Investigation into Cancer-Potsdam, were meta-analyzed. Pooling relative risks adjusted for cardiovascular risk factors not including putative mediators indicated moderate between-study heterogeneity (I2=52.2%). This was explained by the smallest study, and the pooled relative risk (95% confidence interval) before and after its exclusion was 1.03 (0.98-1.08) and 0.99 (0.96-1.01) per 5 µg/mL, respectively. The pooled relative risk (95% confidence interval) additionally adjusted for potential mediators was 1.08 (1.01-1.15) and 1.05 (1.00-1.11) before and after excluding the same study, respectively.

CONCLUSIONS

Adiponectin is not associated with risk of stroke. If anything, adiponectin relates directly to stroke risk after controlling for risk factors that favorably correlate with adiponectin.

Adiponectin and incident coronary heart disease and stroke. A systematic review and meta-analysis of prospective studies

The plasma concentration of adiponectin, an adipokine that has anti-inflammatory, anti-atherogenic and insulin sensitizing properties, is lower in obese subjects and could therefore be a target for therapy. In order to review and meta-analyse prospective cohort studies investigating adiponectin concentration and the risk for incident coronary heart disease (CHD) or stroke, a systematic search of MEDLINE, EMBASE and Cochrane databases was performed. Two independent reviewers selected prospective cohort studies investigating the relationship between adiponectin level and incident CHD or stroke using 'adiponectin' and 'cardiovascular disease' or 'stroke' and their synonyms, excluding patients with clinically manifest vascular disease. Random-effects models were used to calculate pooled relative risks (RRs) and 95% confidence intervals (95% CI). Generalized least squares regression was used to assess dose-response relationships for adiponectin concentrations from studies that provided RRs solely based upon categorical data regression. In total, 16 prospective cohort studies, comprising 23,919 patients and 6,870 CHD or stroke outcome events, were included in the meta-analyses. An increase of 1 standard deviation in log-transformed adiponectin did not lower the risk for CHD (RR 0.97; 95% CI 0.86-1.09). A 10 μg mL(-1) increase in adiponectin conferred a RR of 0.91 (95% CI 0.80-1.03) for CHD and a RR 1.01 (95% CI 0.97-1.06) for stroke. In conclusion, plasma adiponectin is not related to the risk for incident CHD or stroke.

Associations of adiponectin and leptin with incident coronary heart disease and ischemic stroke in african americans: the jackson heart study

BACKGROUND

Because the predictive significance of previously reported racial differences in leptin and adiponectin levels remains unclear, we assessed the prospective association of these adipokines with the risk of cardiovascular disease (CVD) events in African Americans, a population with a high prevalence of cardiometabolic risk factors.

METHODS

Serum specimens from 4,571 Jackson Heart Study participants without prevalent CVD at baseline examination (2000-2004) were analyzed for adiponectin and leptin levels. Cox proportional hazard regression models were used to estimate the associations of the two adipokines with incident coronary heart disease (CHD) and incident ischemic stroke.

RESULTS

During 6.2 years average of follow-up, 98 incident CHD and 87 incident ischemic stroke events were documented. Among study participants (64% women; mean age 54 ± 13 years), the mean (standard deviation, SD) was 6.04 (4.32) μg/mL in women and 4.03 (3.14) μg/mL in men for adiponectin and 37.35 (23.90) ng/mL in women and 11.03 (10.05) ng/mL in men for leptin. After multivariable adjustment that included age, body mass index, high-density lipoprotein cholesterol, triglycerides, C-reactive protein, insulin resistance by homeostasis model assessment for insulin resistance, systolic blood pressure, hypertension medication, smoking, and physical activity, adiponectin was directly associated in women with incident stroke, HR = 1.41 (1.04-1.91) per one SD increase (p = 0.03), but not in men (p = 0.42). It was not associated with incident CHD in women or men. Leptin was not associated with incident CHD or incident stroke.

CONCLUSION

In the largest community-based African American cohort, adiponectin was associated among women with a higher risk of incident stroke. Whether adiponectin harbors harmful properties, or it is produced in response to vascular inflammation to counter the atherosclerotic process, or the putative "adiponectin resistance" phenomenon acts, should be further assessed.

Total and high molecular weight adiponectin levels and risk of cardiovascular disease in individuals with high blood glucose levels

OBJECTIVE

The association of adiponectin levels with cardiovascular disease (CVD) may vary by age and health condition. It is unknown whether adiponectin predicts CVD events among individuals with high blood glucose levels.

METHODS

We conducted a nested case-control study among 15,566 men and women aged 40-85 years from four communities, who were free of CVD at baseline. During 192,181 person-years of follow-up, 117 individuals subsequently developed coronary heart disease or ischemic stroke and had high plasma glucose concentrations (fasting/nonfasting ≥ 5.6/7.2 mmol/L or treated) at baseline. Controls were randomly selected at a 2:1 ratio and matched for sex, age, blood glucose, year of survey, fasting conditions, and community (n = 234). Baseline total and high molecular weight (HMW) adiponectin and their ratio were examined for total subjects and the association with CVD was compared between ages of 40-69 and 70-85 years.

RESULTS

After adjustment for matched variables and traditional risk factors, total and HMW adiponectin and their ratio were not associated with overall risk of CVD. However, significant interactions of the associations between the age groups were found. The highest quartile for HMW adiponectin and HMW/total adiponectin ratio decreased risk of CVD compared with the lowest quartile among middle-aged individuals (multivariable-adjusted odds ratio = 0.33 [95%CI, 0.13-0.83] and 0.47 [0.22-0.98], respectively), while this association was not seen among the elderly.

CONCLUSIONS

High HMW adiponectin levels may decrease the risk of CVD in middle-aged adults with high blood glucose.

Adipokines as mediators of endothelial function and atherosclerosis

For many decades, adipose tissue was considered as an inactive body compartment that was only used as an energy store. During the recent years, an increasing amount of data has revealed that adipose tissue is a major endocrine and paracrine organ producing numerous enzymes, hormones and growth factors which are collectively termed as adipokines. Several experimental and clinical studies showed that adipokines modulate insulin sensitivity and have an influence on glucose/fat metabolism and obesity. Apart from these properties, recent research revealed several direct actions of adipokines on endothelial function, vascular homeostasis and atherogenesis which are independent of their effects on glucose and fat metabolism. The present review focuses on the direct effects of adipokines on vascular/endothelial function and atherosclerosis and summarizes the experimental and clinical data which suggest a role for these molecules as potential diagnostic and prognostic cardiovascular markers as well as potential therapeutic target to reduce cardiovascular risk.

Total and high-molecular-weight adiponectin and risk of coronary heart disease and ischemic stroke in older adults

CONTEXT

Adiponectin is atheroprotective in the laboratory, but prospective studies have shown opposite associations with cardiovascular disease (CVD) in healthy middle-aged populations (protective) and older cohorts (adverse). Whether this relates to different proportions of high-molecular-weight (HMW) adiponectin is unknown.

OBJECTIVE

The aim of the study was to test the hypothesis that total adiponectin is directly associated, but HMW adiponectin is inversely related, with CVD in older adults.

DESIGN, SETTING, AND PARTICIPANTS

We evaluated 3290 participants free of prevalent CVD in a longitudinal cohort study of U.S. adults aged 65 yr and older.

MAIN OUTCOME MEASURES

We measured incident CVD (n = 1291), comprising coronary heart disease and ischemic stroke.

RESULTS

Total and HMW adiponectin were tightly correlated (r = 0.94). Cubic splines adjusted for potential confounders revealed that the associations of total and HMW adiponectin with CVD were U-shaped, with inflection points of 20 and 10 mg/liter, respectively. After controlling for potential confounding, levels of total and HMW adiponectin below these cutpoints tended to be inversely associated with incident CVD, driven by their significant or near-significant relations with coronary heart disease [hazard ratio (HR), 0.85 per sd increase; 95% confidence interval (CI), 0.75-96; and HR, 0.87; 95% CI, 0.75-1.01, respectively]. These associations were abrogated by additional inclusion of putative metabolic intermediates. Above these cutpoints, however, both total and HMW adiponectin were significantly directly associated with CVD after adjustment for confounders and, particularly, mediators (HR, 1.20 per sd increase; 95% CI, 1.06-1.35; and HR, 1.12; 95% CI, 1.02-1.24, respectively).

CONCLUSION

In community-living elders, total and HMW adiponectin showed similar U-shaped relationships with CVD. The inverse relation in the lower range, but not the direct association at the higher end, disappeared after inclusion of putative intermediates, suggesting that high levels may reflect adverse processes separate from adiponectin's beneficial glycometabolic properties.

Adiposity, adipokines, and risk of incident stroke in older men

BACKGROUND AND PURPOSE

The association between adiposity and adipocytes and risk of stroke in older adults is uncertain. We have examined the association between adiposity measures and adipocytes (adiponectin and leptin) with incident stroke events in older men.

METHODS

Prospective study of 3411 men aged 60 to 79 years with no previous diagnosis of myocardial infarction, heart failure, or stroke followed-up for an average of 9 years, during which there were 192 incident major stroke events.

RESULTS

In age-adjusted analyses, body mass index and waist circumference were not significantly associated with risk of stroke in older men, although obese men (body mass index >30 kg/m(2)) showed the lowest risk of stroke. Despite the strong positive correlation between leptin and body mass index and waist circumference, risk of stroke was significantly increased in those in the top quartile of the leptin distribution. The increased risk remained after adjustment for potential confounders, including systolic blood pressure (adjusted hazard ratios top quartile versus bottom quartile: 2.03; confidence interval, 1.27-3.27]). Further adjustment for markers of inflammation (c-reactive protein), endothelial dysfunction (von Willebrand factor), fibrinolytic activity (d-dimer), and γ-glutamyl transferase attenuated the increased risk, but risk remained significantly increased (adjusted hazard ratios, 1.73; confidence interval, 1.06-2.83]). By contrast, no association was seen between adiponectin and risk of stroke.

CONCLUSIONS

Conventional adiposity measures were not associated with increased stroke risk in older men. However, leptin (a good marker of percent fat mass), but not adiponectin, predicted stroke, suggesting a link between fat mass and stroke risk.

Adipocytokines and the risk of ischemic stroke: the PRIME Study

OBJECTIVE

Adipocytokines are hormones secreted from adipose tissue that possibly link adiposity and the risk of cardiovascular disease, but limited prospective data exist on plasma adipocytokines and ischemic stroke risk. We investigated associations and predictive properties of 4 plasma adipocytokines, namely resistin, adipsin, leptin, and total adiponectin, with regard to incident ischemic stroke in the PRIME Study.

METHODS

A cohort of 9,771 healthy men 50 to 59 years of age at baseline was followed up over a period of 10 years. In a nested case-control study, 95 ischemic stroke cases were matched with 190 controls on age, study center, and date of examination. Hazard ratios (HRs) per standard deviation increase in plasma adipocytokine levels were estimated using conditional logistic regression analysis. The additive value of adipocytokines in stroke risk prediction was evaluated by discrimination and reclassification metrics.

RESULTS

Resistin (HR, 1.88; 95% confidence interval [CI], 1.16-3.03), adipsin (HR, 2.01; 95% CI, 1.33-3.04), and total adiponectin (HR, 1.53; 95% CI, 1.01-2.34), but not leptin, were independent predictors of ischemic stroke. The performance of a traditional risk factor model predicting ischemic stroke was significantly improved by the simultaneous inclusion of resistin, adipsin, and total adiponectin (c-statistic: 0.673 [95% CI, 0.631-0.766] vs 0.826 [95% CI, 0.792-0.892], p < 0.001; net reclassification improvement: 38.1%, p < 0.001).

INTERPRETATION

Higher plasma levels of resistin, adipsin, and total adiponectin were associated with an increased 10-year risk of ischemic stroke among healthy middle-aged men. Resistin, adipsin, and total adiponectin provided incremental value over traditional risk factors for the prediction of ischemic stroke risk.

Total and high-molecular weight adiponectin and risk of colorectal cancer: the European Prospective Investigation into Cancer and Nutrition Study

Adiponectin-an adipose tissue-derived protein-may provide a molecular link between obesity and colorectal cancer (CRC), but evidence from large prospective studies is limited. In particular, no epidemiological study explored high-molecular weight (HMW) and non-HMW adiponectin fractions in relation to CRC risk, despite them being hypothesized to have differential biological activities, i.e. regulating insulin sensitivity (HMW adiponectin) versus inflammatory response (non-HMW adiponectin). In a prospective, nested case-control study, we investigated whether prediagnostic serum concentrations of total, HMW and non-HMW adiponectin are associated with risk of CRC, independent of obesity and other known CRC risk factors. A total of 1206 incident cases (755 colon and 451 rectal) were matched to 1206 controls using incidence-density sampling. In conditional logistic regression, adjusted for dietary and lifestyle factors, total adiponectin and non-HMW adiponectin concentrations were inversely associated with risk of CRC [relative risk (RR) comparing highest versus lowest quintile = 0.71, 95% confidence interval (CI) = 0.53-0.95, P(trend) = 0.03 for total adiponectin and RR = 0.45, 95% CI = 0.34-0.61, P(trend) < 0.0001 for non-HMW adiponectin]. HMW adiponectin concentrations were not associated with CRC risk (RR = 0.91, 95% CI = 0.68-1.22, P(trend) = 0.55). Non-HMW adiponectin was associated with CRC risk even after adjustment for body mass index and waist circumference (RR = 0.39, 95% CI = 0.26-0.60, P(trend) < 0.0001), whereas the association with total adiponectin was no longer significant (RR = 0.81, 95% CI = 0.60-1.09, P(trend) = 0.23). When stratified by cancer site, non-HMW adiponectin was inversely associated with both colon and rectal cancer. These findings suggest an important role of the relative proportion of non-HMW adiponectin in CRC pathogenesis. Future studies are warranted to confirm these results and to elucidate the underlying mechanisms.

High-molecular-weight and total adiponectin levels and incident symptomatic peripheral artery disease in women: a prospective investigation

BACKGROUND

Adiponectin is linked to reduced diabetes risk and may be antiatherogenic, yet clinical data show no consistent relationship with incident cardiovascular events, especially among women. To our knowledge, no prior prospective studies have evaluated adiponectin, including high-molecular-weight (HMW) adiponectin, and incident peripheral artery disease (PAD).

METHODS AND RESULTS

We evaluated the relationship of total adiponectin, HMW adiponectin, and the HMW-to-total adiponectin ratio with incident symptomatic PAD in a prospective, nested case-control study conducted within the Women's Health Study (n=110 cases, n=230 controls, frequency matched in strata defined by 5-year age categories, smoking, fasting status, and follow-up time; median cohort follow-up=13.2 years). Baseline median levels of HMW and total adiponectin were significantly lower in women developing PAD than in those remaining event free (HMW: 3.3 versus 3.8 μg/mL, P=0.0005; total: 5.6 versus 7.4 μg/mL, P<0.0001). The ratio did not differ significantly between groups. Age-adjusted PAD odds ratios (95% confidence intervals) across tertiles were 1.0, 0.66 (0.39-1.13), and 0.40 (0.22-0.74) for HMW and 1.0, 0.74 (0.43-1.25), and 0.35 (0.18-0.65) for total adiponectin (P(trend)=0.004 and 0.001, respectively). Results were similar after adjustment for traditional cardiovascular risk factors, use of postmenopausal hormone therapy, high-sensitivity C-reactive protein, soluble intercellular adhesion molecule-1, leptin, hemoglobin A(1c), and fasting insulin (adjusted odds ratio and 95% confidence interval for HMW: 1.0, 0.62 [0.29-1.34], 0.30 [0.12-0.74]; total: 1.0, 0.46 [0.22-1.00], 0.30 [0.12-0.76]; P(trend)=0.01 for both).

CONCLUSIONS

Total and HMW adiponectin are inversely associated with incident PAD among initially healthy women. These prospective data support a protective role for this adipokine in peripheral atherosclerosis development.

Adipocytokines and ischemic stroke: differential associations between stroke subtypes

OBJECTIVE

Experimental studies have indicated that adipocytokines are associated with vascular diseases with regard to the pathology of atherosclerotic plaque. We hypothesized that the strength of the associations between adipocytokines and stroke would differ between ischemic stroke subtypes.

METHODS

A total of 96 acute ischemic stroke patients (within 5 days from onset) and 48 non-stroke subjects were analyzed in this study. Stroke patients were comprised of 26 strokes due to large artery atherosclerosis (LAA) and 72 non-LAA strokes. Venous blood from all participants was drawn after an overnight fast, and serum levels of leptin, adiponectin and resistin were measured by multiple sandwich immunoassay techniques.

RESULTS

Compared with non-LAA strokes, patients with LAA strokes had lower levels of serum adiponectin (6.4 ± 3.1 vs. 8.5 ± 3.9 μg/mL; P=0.04), and a higher level of leptin-to-adiponectin ratio (L:A ratio; 1.6 ± 1.4 vs. 0.9 ± 0.9; P<0.01). Multinomial logistic regression analyses showed that, although none of the adipocytokines was associated with non-LAA strokes, lower adiponectin (adjusted OR, 0.79 per 1-μg/mL increase; 95% CI, 0.64-0.98), higher leptin (aOR, 1.12 per 1-ng/mL increase; 95% CI, 1.004-1.25) and higher L:A ratio (aOR, 2.93 per 1-quartile increase; 95% CI, 1.39-6.15) showed significant associations with increased odds of having LAA stroke, compared to non-stroke subjects.

CONCLUSION

From our study, we documented that leptin and adiponectin had differential association patterns with ischemic stroke according to the stroke subtype. Careful consideration of the heterogeneity of stroke subtypes would be warranted in studying the utility of biomarkers including adipocytokines.

Resistin, but not adiponectin and leptin, is associated with the risk of ischemic stroke among postmenopausal women: results from the Women's Health Initiative

BACKGROUND AND PURPOSE

Adipose tissue is considered an endocrine organ that secretes adipokines, which possibly mediate the effects of obesity on the risk of cardiovascular disease. However, there are yet limited prospective data on the association between circulating adipokine levels and the risk of ischemic stroke. We aimed to examine the associations of 3 adipokines (adiponectin, leptin, and resistin) with the risk of ischemic stroke.

METHODS

We conducted a prospective nested case-control study (972 stroke cases and 972 matched control subjects) within the Women's Health Initiative Observational Study cohort. The control subjects were matched to cases on age, race/ethnicity, date of study enrollment, and follow-up time.

RESULTS

Adipokine levels were associated with established stroke risk factors such as obesity and systolic blood pressure. Adjusted for body mass index, the ORs for incident ischemic stroke comparing the highest (Quartile 4) with the lowest quartile (Quartile 1) were 0.81 (95% CI, 0.61 to 1.08; P trend=0.068) for adiponectin, 1.15 (95% CI, 0.83 to 1.59; P trend=0.523) for leptin, and 1.57 (95% CI, 1.18 to 2.08; P trend=0.002) for resistin. The association for resistin remained significant even after accounting for established stroke risk factors (OR, 1.39; 95% CI, 1.01 to 1.90; P trend=0.036). Further adjustment for markers for inflammation, angiogenesis, and endothelial function also did not affect our results.

CONCLUSIONS

Circulating levels of resistin, but not those of adiponectin or leptin, are associated with an increased risk of incident ischemic stroke in postmenopausal women, independent of obesity and other cardiovascular disease risk factors.

Emerging risk factors in women

Stroke is a major cause of long-term disability and death for women in the United States, with recent evidence suggesting a higher rate of stroke in midlife women than men, as well as higher lifetime risk of stroke for older women. Several recent studies highlight emerging areas of interest for research on risk factors for stroke in women. This article reviews data published in the last year, focusing on 3 potential risk factors that may partially explain these differences between men and women: central adiposity and related adipocytokines, endogenous sex hormones, and depression.