Deleterious Impact of “High Normal” Glucose Levels and Other Metabolic Syndrome Components on Arterial Endothelial Function and Intima-Media Thickness in Apparently Healthy Chinese Subjects: The CATHAY Study

A Potential Strategy for Atherosclerosis Prevention in Modernizing China - Hyperhomocysteinemia, MTHFR C677T Polymorphism and Air Pollution (PM2.5) on Atherogenesis in Chinese Adults

BACKGROUND

Atherosclerosis is one of the most important global health hazards and air pollution (AP, PM2.5) has been implicated. In addition to traditional risk factors hyperhomocysteinemia (HC) has been recognized in many parts of China related to risk of stroke.

METHODS

To evaluate the impact of HC (homocysteine >14μmol/l) and PM2.5 air pollution on atherogenesis in modernizing China, we studied 756 asymptomatic Chinese in China from 1998-2007. PM2.5 exposure, HC, folate, and methylenetetrahydrofolate reductase (MTHFR) C/T genotype were evaluated. Brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. Locations were categorized as zones 1, 2 and 3, with increasing PM2.5 exposure.

RESULTS

HC was higher (19.4±13.1 and 27.1±25.1μmol/l) in high PM2.5-polluted zones 2 and 3 than in zone 1 (9.7±4.5μmol/l, p<0.0015). The top HC tertile was characterized by lower folate and vitamin B12, but a higher proportion of the MTHFR TT genotype, Metabolic Syndrome (MS) and PM2.5 level (p=0.0018). FMD was significantly lower (7.3±2.3%) and carotid IMT thicker (0.63±0.12mm) in the top HC tertile, compared with low HC tertile (8.4±2.5%, p<0.0001; 0.57±0.1mm, p<0.0001 respectively). Similar differences in FMD and IMT were seen in zones 2 and 3, compared with zone 1 (p<0.0001). On multivariate regression, HC was related to male gender (beta=0.106, p=0.021), MTHFR-TT (beta=0.935, p<0.0001), locations (beta=0.230, p<0.0001) and folate-MTHFR interaction (beta=-0.566, p<0.0001). FMD was related to age (beta= -0.221; p<0.0001), male gender (beta= -0.194, p=0.001) PM2.5 and location (beta=-0.285 to -0.303, p<0.0001). Carotid IMT was related to PM2.5 (beta=0.173, p<0.0001), HC (0.122, p=0.006) but not to MTHFR or location, independent of age, gender, MS, and LDL-C. No significant HC-PM2.5 interaction effect on FMD and IMT was observed.

CONCLUSION

HC and PM2.5 pollution but not MTHFR genotype were both related to carotid IMT, independent of other traditional risk factors. This has potential implications in dietary and AP strategies for atherosclerosis prevention in China.

The Different Impact of PM2.5 on Atherogenesis in Overseas vs. Native Chinese in the CATHAY Study

Air pollution (PM2.5) has been associated with cardiovascular disease (CVD) globally and with early atherosclerosis surrogate markers in modernized China. A sizeable number of Chinese have migrated overseas, with an increase in their vulnerability to CVD. To evaluate the impact of PM2.5 air pollution on atherogenesis in native vs. overseas Chinese, we recruited 756 asymptomatic native Chinese and 507 age- and gender-matched overseas Chinese from Sydney and San Francisco. Their cardiovascular profiles were evaluated. PM2.5 was derived from remote sensing technology; atherosclerosis surrogate markers, flow-mediated dilation (FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. The native Chinese had a higher proportion of smokers as well as higher blood pressure, glucose, metabolic syndrome and PM2.5 exposure (p < 0.001), but lower lipids and folate than the overseas Chinese (p < 0.0001). Carotid IMT was lower in the native Chinese (p < 0.0001), but the other vascular parameters were similar. A multivariate regression revealed that FMD in the native Chinese was related to the male gender, age and location; in the overseas Chinese, it was related to age, but not to PM2.5. Carotid IMT in the native Chinese was related to PM2.5, independent of atherosclerotic risk factors and location (R2 = 0.384, F = 34.5, p < 0.0001) whereas in the overseas Chinese, IMT was related to the male gender and age, but not to PM2.5 or overseas location (R2 = 0.282, F = 19.7, p < 0.0001). PM2.5 had a greater impact on atherogenesis in the native Chinese, independent of traditional risk factors, with implications for preventive strategies.

Dietary inflammatory index and cardiorenal function in women with diabetes and prediabetes

BACKGROUND AND AIMS

Previous studies had shed a new light on the importance of multiple inflammatory mechanisms in the pathogenesis of arterial stiffness. The dietary inflammatory index (DII®) is a new tool for estimating the overall inflammatory potential of the diet. The aim of this study is to assess the association of the inflammatory potential of diet with peripheral arterial stiffness and renal function in women with diabetes and prediabetes.

METHODS AND RESULTS

This is an observational cross-sectional study. A total of 2644 females aged 45-75 years were included for the study. Dietary intake in the past 12 months was assessed by a validated China National Nutrition and Health Survey 2002 (CNHS2002) food-frequency questionnaire. Energy-adjusted DII (E-DII) scores were calculated from daily dietary information. In a multivariable linear regression analysis adjusted for potential confounders, E-DII was positively associated with brachial ankle pulse wave velocity (baPWV) in participants with diabetes (β = 12.820; 95% CI = 2.565, 23.076; P = 0.014) and prediabetes (β = 29.025; 95% CI = 1.110, 56.940; P = 0.042), but not in females with normal glucose homeostasis. In addition, per unit increase of E-DII was significantly associated with lower eGFR (β = -1.363; 95% CI = -2.335, -0.392; P = 0.006) in patients with diabetes.

CONCLUSION

We identified a direct association between E-DII and arterial stiffness, decreasedeGFR in middle-aged and elderly women with diabetes or prediabetes. Future studies are needed to verify and clarify the role of E-DII as an intervention target for cardiorenal complications of chronic hyperglycemia.

The impact of particulate matter air pollution (PM2.5) on atherosclerosis in modernizing China: a report from the CATHAY study

BACKGROUND

Air pollution has been associated with an increase in cardiovascular diseases incidence. To evaluate whether air pollution can accelerate atherogenic processes, we assessed the effects of air pollution on important surrogate markers of atherosclerosis [brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT)].

METHODS

A total of 1656 Han Chinese (mean age 46.0 + 11.2 years; male 47%) in Hong Kong, Macau, Pun Yu, Yu County and the 3-Gorges Territories (Yangtze River) were studied between 1996 and 2007 [Chinese Atherosclerosis in the Aged and Young Project (the CATHAY Study)]. Cardiovascular risk profiles were evaluated. Particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) parameters were computed from satellite sensors. Brachial FMD and carotid IMT were measured by ultrasound.

RESULTS

Health parameters [age, gender, body mass index, waist : hip ratio (WHR) and glucose)] were similar in lowest and highest PM2.5 exposure tertiles, systolic and diastolic blood pressures and triglycerides were higher (P < 0.001) and low-density cholesterol (LDL-C) was lower in the top PM2.5 tertile (P < 0.001). Brachial FMD [7.84 ± 1.77, 95% confidence interval (CI) 7.59-8.10%, vs 8.50 ± 2.52, 95% CI 8.23-8.77%, P < 0.0001) was significantly lower and carotid IMT (0.68 ± 0.13 mm, 95% CI 0.67-0.69 mm vs 0.63 mm ± 0.15 mm 95% CI 0.62-0.64 mm; P < 0.0001) was significantly thicker in the top PM2.5 tertile compared with the lowest tertile. On multiple regression, FMD was inversely related to PM2.5 (beta = 0.134, P = 0.015) independent of gender, age and blood pressure (model R2 = 0.156, F-value = 7.6, P < 0.0001). Carotid IMT was significantly correlated with PM2.5 exposure (beta = 0.381, P < 0.0001) independent of age, location, gender, WHR, blood pressure and LDL-C (model R2 = 0.408, F-value = 51.4, P-value <0.0001).

CONCLUSIONS

Air pollution is strongly associated with markers of early atherosclerosis, suggesting a potential target for preventive intervention.

Reversion From Pre-Diabetes Mellitus to Normoglycemia and Risk of Cardiovascular Disease and All-Cause Mortality in a Chinese Population: A Prospective Cohort Study

Background

It is unclear whether reversion from pre–diabetes mellitus to normoglycemia reduces cardiovascular disease (CVD) and all‐cause mortality risk in a Chinese population. We aimed to fill this research gap.

Methods and Results

The current study included 14 231 Chinese participants (mean age, 58.08 years) who were free from myocardial infarction and stroke at the time of survey participation (2006–2007 and 2008–2009). Participants were divided into 3 categories according to the 2‐year changes in pre–diabetes mellitus, defined by fasting plasma glucose: those with progression to diabetes mellitus, those with reversion from pre–diabetes mellitus to normoglycemia, and those with persistent pre–diabetes mellitus. Cox proportional hazards models were used to calculate hazard ratios (HRs) and their 95% CIs for CVD and all‐cause mortality. After a median follow‐up period of 8.75 years, a total of 879 CVD events (including 180 myocardial infarction events and 713 stroke events) and 941 all‐cause mortality events were recorded. After adjustment for confounding factors, reversion from pre–diabetes mellitus to normoglycemia was associated with decreased risks of CVD (HR, 0.78; 95% CI, 0.64–0.96), myocardial infarction (HR, 0.62; 95% CI, 0.40–0.97), stroke (HR, 0.79; 95% CI, 0.63–0.98), and all‐cause mortality (HR, 0.82; 95% CI, 0.68–0.99) compared with progression to diabetes mellitus.

Conclusions

Reversion from fasting plasma glucose–defined pre–diabetes mellitus to normoglycemia was associated with a reduction in the future risk of CVD and all‐cause mortality in a Chinese population.

Registration

URL: https://www.chictr.org; Unique identifier: ChiCTRTNC‐11001489.

Vitamins B-12 and C Supplementation Improves Arterial Reactivity and Structure in Passive Smokers: Implication in Prevention of Smoking-Related Atherosclerosis

BACKGROUND

Atherosclerosis is an important medical problem of modern society. High environmental tobacco smoke in casino is associated with an accelerated atherogenic process. We have previously shown vitamin B12 and C supplementation improves vascular reactivity and may be beneficial in vascular protection.

OBJECTIVE

To evaluate the impact of vitamin supplementation on atherosclerosis (brachial artery reactivity FMD and carotid intima-media thickness IMT) in subjects exposed to high environmental tobacco smoke.

DESIGN

Double-blind 2x2 factorial design fashion.

SETTING

Computer randomization in 4 treatment groups: placebo (n=24), vitamin B12 (n=21), vitamin C (n=23) and vitamin B12+C (n=23) groups.

PARTICIPANTS

91 passive-smoking casino employees (19.2% male, mean age 45.0±8.2 years).

INTERVENTION

Subjects were randomized to receive vitamin B12 (500µg daily), vitamin C (200mg daily), vitamin B12+C or image-matched placebo capsules for 1 year.

MEASUREMENT

Brachial FMD and carotid IMT (surrogate atherosclerotic markers) were measured by ultrasound at baseline and on completion at 12 months.

METHODS

91 passive smoking casino employees (19.2% male, mean age 45.0±8.2 years) were randomized to receive vitamin B12 (500µg daily), vitamin C (200mg daily), vitamin B12+C or image-matched placebo capsules in double-blind 2 x 2 factorial design fashion for 1 year. Brachial FMD and carotid IMT (surrogate atherosclerotic markers) were measured by ultrasound at baseline and 12 months.

RESULTS

Of the 78 (85.7%) passive-smoking employees completed the study, 11.5% had hypertension, 5.1% diabetes mellitus and 15.4% hypercholesterolemia. There were no significant changes in their blood pressures, lipid profiles, glucose and body mass index after supplementation for 1 year, but mild decrease in DBP (p<0.001) and blood creatinine (p<0.01) after combined vitamin B12 and C, and significant increase in blood B12 after vitamin B12 (p<0.01) and vitamin B12+C supplementations (p<0.001). Brachial FMD and cartotid IMT improved after the 3 vitamin supplementations (p<0.001), but not after placebo, being more significant after combined vitamin supplementations (p<0.0001). No adverse effects were reported.

CONCLUSION

Vitamin B12 or C supplementation in passive smokers improved vascular reactivity and structures at 1 year, with implication in long term atherosclerosis prevention.

Biological pathways underlying the association between habitual long-sleep and elevated cardiovascular risk in adults

Cardiovascular disease is the leading cause of death in the world. In addition to non-modifiable factors such as age and sex, cardiovascular risk is also driven by behavioral, and therefore somewhat modifiable, factors such as physical activity, diet, and sleep. It is well established that sleep duration has a U-shaped association with mortality and cardiovascular disease, with recent evidence suggesting that this association is observed even while controlling for the effects of comorbid conditions. Whereas several biological mechanisms mediating the association between chronic short sleep duration and cardiovascular risk have been established, the biological mechanisms underlying the relationship between habitual long sleep (≥9 h) duration and cardiovascular risk, in the absence of other chronic diseases, are not well understood. This review will focus on summarizing the literature investigating the mechanisms underlying the association between habitual long sleep duration and cardiovascular risk. We will also propose the mechanistic pathways, distinct from the ones for short sleep, by which habitual long sleep can increase cardiovascular disease.

Fasting blood glucose and risk of Stroke: A Dose-Response meta-analysis

BACKGROUND & PURPOSE

A growing number of studies have shown that fasting blood glucose is related to the risk of stroke, however, the dose-response association between fasting blood glucose and the risk of stroke is still unclear. Accordingly, we conducted a dose-response meta-analysis to evaluate the relationship between fasting blood glucose and the risk of stroke by summarizing cohort studies.

METHODS

PubMed and Embase databases were searched for related studies (until October 2020). Cohort studies examining the influence of fasting blood glucose on stroke risk were summarized. A dose-response relationship was determined using a random-effect model.

RESULTS

Eighteen cohort studies involving 2,555,666 participants were included. The pooled relative risk for the high-versus-low categories was 1.79 (95% CI: 1.68-1.91) in all people, and 1.16 (95% CI: 1.11-1.21) in non-diabetic people. In addition, there was a non-linear relationship between fasting blood glucose and stroke risk. The incidence of stroke was reduced to its lowest point when fasting blood glucose level was 70-100 mg/dL.

CONCLUSION

Fasting blood glucose was positively related to stroke risk, with a non-linear dose-response relationship.

Association of early-onset diabetes, prediabetes and early glycaemic recovery with the risk of all-cause and cardiovascular mortality

AIMS/HYPOTHESIS

The increasing incidence of diabetes among young adults is a disease burden; however, the effects of early-onset diabetes, prediabetes and glycaemic recovery on CVD or mortality remain unclear. We aimed to investigate the association of these factors with 10 year all-cause mortality, CVD mortality and CVD incidence in Korean young adults.

METHODS

This large and longitudinal cohort study included data from the Korean National Health Insurance Service-National Health Information Database; 2,502,375 young adults aged 20-39 years without diabetes mellitus and CVD at baseline were included. Glycaemic status was measured twice, first in 2002-2003 and second in 2004-2005. Changes in fasting glucose levels were evaluated according to fasting glucose status: normal fasting glucose (NFG; <5.5 mmol/l), impaired fasting glucose (IFG; 5.5-6.9 mmol/l), and diabetic fasting glucose (DFG; ≥7.0 mmol/l). Primary outcomes were all-cause and CVD mortality risk. The secondary outcome was incidence of CVD, including acute myocardial infarction and stroke. All outcomes arose from the 10 year follow-up period 1 Jan 2006 to 31 December 2015.

RESULTS

Individuals with NFG at baseline, who were subsequently newly diagnosed with diabetes and prediabetes (IFG), had increased all-cause mortality (HR [95% CI] 1.60 [1.44, 1.78] and 1.13 [1.09, 1.18], respectively) and CVD incidence (1.13 [1.05, 1.23] and 1.04 [1.01, 1.07], respectively). In those with DFG at baseline, early recovery to NFG and IFG was associated with decreased all-cause mortality (0.57 [0.46, 0.70] and 0.65 [0.53, 0.81], respectively) and CVD incidence (0.70 [0.60, 0.81] and 0.78 [0.66, 0.91], respectively). Among patients with IFG at baseline, early recovery to NFG was associated with decreased CVD mortality (0.74 [0.59, 0.93]).

CONCLUSIONS/INTERPRETATION

Early-onset diabetes or prediabetes increased CVD risks and all-cause mortality after the 10 year follow-up. Furthermore, recovery of hyperglycaemia could reduce the subsequent 10 year risk for CVD incidence and all-cause mortality. Graphical abstract.

Endothelial function in patients with atrial fibrillation

Atrial fibrillation (AF) is the most common heart arrhythmia and is associated with poor outcomes. The adverse effects of AF are mediated through multiple pathways, including endothelial dysfunction, as measured by flow-mediated dilatation. Flow-mediated dilatation has demonstrated endothelial dysfunction in several conditions and is associated with poor outcomes including mortality, yet can be improved with medical therapy. It is thus a useful tool in assessing endothelial function in patients. Endothelial dysfunction is present in patients with AF and is associated with poor outcomes. These patients are generally older and have other co-morbidities such as hypertension, hypercholesterolaemia and diabetes. The precise process by which AF is affiliated with endothelial damage/dysfunction remains elusive. This review explores the endothelial structure, its physiology and how it is affected in patients with AF. It also assesses the utility of flow mediated dilatation as a technique to assess endothelial function in patients with AF. Key MessagesEndothelial function is affected in patients with atrial fibrillation as with other cardiovascular conditions.Endothelial dysfunction is associated with poor outcomes such as stroke, myocardial infarction and death, yet is a reversible condition.Flow-mediated dilatation is a reliable tool to assess endothelial function in patients with atrial fibrillation.Patients with atrial fibrillation should be considered for endothelial function assessment and attempts made to reverse this condition.

Comparison of the Effects of Fasting Glucose, Hemoglobin A1c, and Triglyceride-Glucose Index on Cardiovascular Events in Type 2 Diabetes Mellitus

The triglyceride–glucose (TyG) index has been correlated with insulin resistance. We aim to investigate the role of the TyG index on cardiovascular (CV) events in type 2 diabetes mellitus and compare the roles of fasting glucose, hemoglobin A_1c, and the TyG index in predicting CV events. This retrospective study enrolled 3524 patients with type 2 diabetes from the Kaohsiung Medical University Research Database in 2009 in this longitudinal study and followed them until 2015. The TyG index was calculated as log (fasting triglyceride level (mg/dL) × fasting glucose level (mg/dL)/2). CV events included myocardial infarction, unstable angina, stroke, hospitalization for coronary artery disease, peripheral artery disease, and CV-related death. The association between variables and CV events was assessed using a multivariable stepwise Cox proportional hazard analysis. Two hundred and fifteen CV events (6.1%) were recorded during a follow-up period of 5.93 years. The multivariable stepwise analysis showed that high fasting glucose (HR, 1.007; p < 0.001) and a high TyG index (HR, 1.521; p = 0.004) but not hemoglobin A_1c or triglycerides were associated with a higher rate of CV events. Adding fasting glucose and the TyG index to the basic model improved the predictive ability of progression to a CV event (p < 0.001 and p = 0.018, respectively), over that of hemoglobin A_1c (p = 0.084) and triglyceride (p = 0.221). Fasting glucose and the TyG index are useful parameters and stronger predictive factors than hemoglobin A_1c and triglyceride for CV events and may offer an additional prognostic benefit in patients with type 2 diabetes.

A Tale of Three Gorges in the Yangtze River: Comparing the Prevalence of Metabolic Syndrome According to ATPIII, WHO, and IDF Criteria and the Association with Vascular Health in Modernizing China

BACKGROUND

Metabolic syndrome (MS) is associated with atherosclerotic diseases. The prevalence of MS according to the Adult Treatment Panel III (ATPIII), World Health Organization (WHO), and International Diabetes Federation (IDF) criteria are variable but increasing in western countries and modernizing China. This study aimed to evaluate the prevalence of MS according to these three criteria, in farmers or ex-farming residents in three-gorges territories undergoing rapid lifestyle changes.

METHODS

We compared 95 residents (ex-farmers) in Wu Shan (WS) (28.4% men, aged 49.7 ± 9 years) resettled uphill for 3-5 years, and 87 age- and gender-matched farmers in Da Chang (DC) (27.6% men, aged 48.8 ± 10 years) before migration. MS and other traditional risk factors were assessed and carotid intima-media thickness (IMT) measured.

RESULTS

Ninety-nine percent of WS residents were retired or adopted nonfarming jobs. Compared with DC farmers, WS ex-farmers had higher waist circumference, low density lipoprotein-cholesterol, and triglycerides (P < 0.0001), but their blood pressures, HDL-cholesterol, and fasting glucose were similar. MS were identified in 43.2% (IDF), 36.8% (WHO), and 29.5% (ATPIII) respectively in WS ex-farmers, compared with 17.2%, 13.8%, and 11.5% respectively in DC farmers. Carotid IMT was significantly higher in WS ex-farmers (0.74 ± 0.16 mm) than in DC farmers (0.64 ± 0.11 mm) (P < 0.0001). On multivariate regression analysis, prevalence of MS was correlated with job nature (beta = 0.425, P < 0.0001). Carotid IMT was better correlated with IDF MS criteria (beta = 0.208, P = 0.021), independent of age and WS location (regression adjusted R² = 0.444, F-value 12.0, P < 0.0001), but not with the ATPIII or WHO criteria.

CONCLUSIONS

IDF MS criteria is more sensitive, better correlates with atherosclerosis surrogate, and accordingly is more readily applicable to modernizing China.

Insulin resistance and chronic kidney disease progression, cardiovascular events, and death: findings from the chronic renal insufficiency cohort study

BACKGROUND

Insulin resistance contributes to the metabolic syndrome, which is associated with the development of kidney disease. However, it is unclear if insulin resistance independently contributes to an increased risk of chronic kidney disease (CKD) progression or CKD complications. Additionally, predisposing factors responsible for insulin resistance in the absence of diabetes in CKD are not well described. This study aimed to describe factors associated with insulin resistance and characterize the relationship of insulin resistance to CKD progression, cardiovascular events and death among a cohort of non-diabetics with CKD.

METHODS

Data was utilized from Chronic Renal Insufficiency Cohort Study participants without diabetes (N = 1883). Linear regression was used to assess associations with insulin resistance, defined using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The relationship of HOMA-IR, fasting glucose, hemoglobin A1c (HbA1c), and C-peptide with CKD progression, cardiovascular events, and all-cause mortality was examined with Cox proportional hazards models.

RESULTS

Novel positive associations with HOMA-IR included serum albumin, uric acid, and hemoglobin A1c. After adjustment, HOMA-IR was not associated with CKD progression, cardiovascular events, or all-cause mortality. There was a notable positive association of one standard deviation increase in HbA1c with the cardiovascular endpoint (HR 1.16, 95% CI: 1.00-1.34).

CONCLUSION

We describe potential determinants of HOMA-IR among a cohort of non-diabetics with mild-moderate CKD. HOMA-IR was not associated with renal or cardiovascular events, or all-cause mortality, which adds to the growing literature describing an inconsistent relationship of insulin resistance with CKD-related outcomes.

Non-alcoholic fatty liver disease and cerebral small vessel disease in Korean cognitively normal individuals

We aimed to investigate the association between nonalcoholic fatty liver disease (NAFLD) and cerebral small vessel disease (CSVD) burden, especially according to the NAFLD severity. A total of 1,260 participants were included. The CSVD burden was assessed with white matter hyperintensities (WMH), lacunes, and microbleeds (MBs) on brain MRI. An ultrasound diagnosis of fatty liver was made based on standard criteria, and the Fibrosis-4 (FIB-4) index was used to classify participants with NAFLD with having a high-intermediate (FIB-4 ≥1.45) or low (FIB-4 < 1.45) probability of advanced fibrosis. A multivariable logistic regression analysis was used to assess the association between NAFLD and the presence of moderate to severe WMH, lacunes, and MBs. NAFLD had a significant association only with moderate to severe WMH (OR: 1.64, 95% CI: 1.10-2.42), even after controlling for cardiometabolic risk factors. A linear trend test showed a significant association between the severity of NAFLD fibrosis and the presence of moderate to severe WMH (p for trend <0.001). Our findings suggest that NAFLD, especially NAFLD with fibrosis, has a significant association with the presence of moderate to severe WMH in cognitively normal individuals, and NAFLD severity predicted more frequent moderate to severe WMH.

The effect of change in fasting glucose on the risk of myocardial infarction, stroke, and all-cause mortality: a nationwide cohort study

Background

The effect of change in blood glucose levels on the risk of cardiovascular disease among individuals without diabetes is currently unclear. We aimed to examine the association of change in fasting serum glucose with incident cardiovascular disease and all-cause mortality among representative large population.

Methods

We analyzed the data from retrospective cohort of Korean National Health Insurance Service. In total, 260,487 Korean adults aged over 40 years, without diabetes mellitus and cardiovascular disease at baseline measured change in fasting serum glucose according to the criteria of impaired and diabetic fasting glucose status: normal fasting glucose (NFG, fasting glucose: < 100 mg/dL), impaired fasting glucose (IFG, fasting glucose: 100.0–125.9 mg/dL), and diabetic fasting glucose (DFG, fasting glucose: ≥ 126.0 mg/dL). Compared to the persistently unchanged group (i.e. NFG to NFG or IFG to IFG), Cox proportional hazards regression analyses were performed in the changed group to obtain the hazards ratio (HR) with 95% confidence interval (CI) for the subsequent median 8-year myocardial infarction, stroke, and all-cause mortality.

Results

Compared to individuals with persistent NFG (i.e., NFG to NFG), individuals who shifted from NFG to DFG had an increased risk of stroke (HR [95% CI]: 1.19 [1.02–1.38]) and individuals who shifted from NFG to IFG or DFG had increased risks of all-cause mortality (HR [95% CI]: 1.08 [1.02–1.14] for NFG to IFG and 1.56 [1.39–1.75] for NFG to DFG). Compared to individuals with persistent IFG, individuals who shifted from IFG to DFG had an increased risk of MI and all-cause mortality (HR [95% CI]: 1.65 [1.20–2.27] and 1.16 [1.02–1.33], respectively).

Conclusions

Increasing fasting glucose in non-diabetic population is associated with risks of the MI, stroke, and all-cause mortality, which is more rapid, more severe.

Electronic supplementary material

The online version of this article (10.1186/s12933-018-0694-z) contains supplementary material, which is available to authorized users.

Effect of post-cessation hyperglycemia on cardiovascular disease and mortality among middle-aged men: an eight-year longitudinal study

Smoking cessation reduces the risk of cardiovascular disease (CVD), but also elevates fasting serum glucose (FSG) levels. The effect of post-cessation hyperglycemia on cardiovascular disease is unknown. The study population consisted of 127,066 men without type 2 diabetes from the Korean National Health Insurance System – Health Screening Cohort database. Change in smoking habits and FSG was determined by the difference in smoking status and FSG levels from the first (2002 and 2003) and second (2004 and 2005) health examinations. Continual smokers, quitters, ex-smokers, and never smokers were stratified according to FSG elevation. The study participants were followed-up for CVD and CVD-related death from 2006 to 2013. Compared to continual smokers, quitters had decreased risk of CVD among those without FSG elevation (hazard ratio, HR, 0.76, 95% confidence interval, CI, 0.66–0.86) and with FSG elevation (HR 0.83, 95% CI 0.72–0.96). Similarly, quitters had a tendency towards reduced risk of CVD-related death among those without FSG elevation (HR 0.74, 95% CI 0.51–1.09) and with FSG elevation (HR 0.68, 95% CI 0.46–1.03). Post-cessation hyperglycemia did not attenuate the beneficiary risk-reducing effects of quitting on CVD and CVD-related death.

Longitudinal Change in Fasting Blood Glucose and Myocardial Infarction Risk in a Population Without Diabetes

OBJECTIVE

To examine the change in fasting blood glucose (FBG) during repeated assessments over time and its potential impact on the risk of developing myocardial infarction (MI).

RESEARCH DESIGN AND METHODS

This prospective cohort study included 68,297 participants without diabetes (mean age 49 years) who were free of MI, stroke, and cancer prior to or in 2010 (baseline of the current analysis). FBG concentrations were measured in 2006, 2008, and 2010. The FBG trajectories during 2006-2010, the primary exposure of the current study, were identified by latent mixture modeling. Incident MI cases were confirmed via review of medical records by cardiologists.

RESULTS

We identified five discrete FBG trajectories according to FBG range and changing pattern over time: elevated-stable (n = 3,877), elevated-decreasing (n = 7,060), moderate-increasing (n = 10,298), moderate-stable (n = 40,352), and low-stable (n = 6,710). During 4 years of follow-up, we documented 283 incident MI cases. Relative to the moderate-stable pattern (FBG ranged from 4.9 to 5.1 mmol/L), adjusted hazard ratios (HRs) were 1.53 (95% CI 1.04, 2.26) for the elevated-stable pattern (FBG ranged from 6.1 to 6.3 mmol/L) and HR 0.61 (95% CI 0.38, 0.98) for the elevated-decreasing pattern (FBG decreased from 6.0 to 5.4 mmol/L), after adjustment for potential confounders such as age, sex, lifestyle factors, obesity, medical history, blood pressure, blood lipids, and C-reactive protein. Consistently, cumulative average and increasing rate of FBG during 2006-2010, but not a single baseline FBG, predicted future risk of MI.

CONCLUSIONS

We found that discrete FBG trajectories were significantly associated with subsequent risk of MI in individuals without diabetes. These observations suggest that long-term trajectories of FBG may be important for risk prediction of MI and possibly other macrovascular diseases.

Grading effect of abnormal glucose status on arterial stiffness and a new threshold of 2-h post-load glucose based on a Chinese community study

AIMS/INTRODUCTION

To investigate the relationship between various glucose metabolic status and arterial stiffness, and further explore the threshold of blood glucose indices for the risk of arterial stiffness.

MATERIALS AND METHODS

The present cross-sectional study included 4,851 individuals from a Chinese community. Overnight fasting blood glucose and 2-h post-load glucose were sampled. Arterial stiffness was measured as brachial-ankle pulse wave velocity. The association was examined using generalized linear regression models. The threshold effect was explored using two piecewise linear regression models by the smoothing plot.

RESULTS

After adjustment for covariates, isolated impaired fasting glucose, isolated impaired glucose tolerance, combined glucose intolerance and newly diagnosed diabetes mellitus were associated with a greater risk of arterial stiffness compared with normal glucose tolerance (B = 18.09, 95% confidence interval [CI] 0.42-35.76, P = 0.045; B = 28.51, 95% CI: 3.40-53.62, P = 0.026; B = 60.70, 95% CI: 38.37-83.04, P < 0.001; B = 95.06, 95% CI: 71.88-118.25, P < 0.001, respectively). Furthermore, there was a non-linear relationship between 2-h post-load glucose and arterial stiffness. A threshold for 2-h post-load glucose of 6.14 mmol/L was observed for the risk of arterial stiffness.

CONCLUSIONS

Impaired fasting glucose, impaired glucose tolerance, combined glucose intolerance and newly diagnosed diabetes mellitus were related to a greater risk of arterial stiffness compared with normal glucose levels. A threshold for 2-h post-load glucose of 6.14 mmol/L probably exists for the risk of arterial stiffness.

Brief Report: Progression of Atherosclerosis in HIV-Infected Individuals-Prospective Data From an Asian Cohort

BACKGROUND

The magnitude and risk factors of progression of atherosclerosis in Asian HIV-infected individuals were unknown. This study aimed to evaluate: (1) the rate of progression of atherosclerosis in HIV-infected individuals, and (2) metabolic and inflammatory parameters that may predict atherosclerosis progression in HIV-infected individuals in an Asian cohort.

SETTING

A prospective, longitudinal study was performed among adults attending an HIV Metabolic clinic in Hong Kong.

METHODS

Carotid intima media thickness (cIMT) was measured at baseline and 24 months. Body composition, metabolic, and inflammatory biomarkers [including homeostasis model assessment of insulin resistance, LDL (low-density lipoprotein) cholesterol particle size, high-sensitive C reactive protein, adiponectin] associated with cIMT change were analyzed; their predictive performances were estimated using receiver operating characteristic analyses.

RESULTS

Sixty-one HIV-infected individuals (mean ± SD age 49.8 ± 11.4 years, 89% men, 97% Chinese, diabetes 39%, hypertension 30%, and dyslipidemia 85%) were recruited. Annual rate of change of cIMT was +0.0075 (0.0000-0.0163) mm/yr, and 19% developed new plaque at 24 months. Two patients died during the study period, 1 because of sudden cardiac death. Using receiver operating characteristic analyses, combination of lower limb fat percentage, LDL cholesterol subclass pattern B, and lower adiponectin level, but not Framingham score, predicted greater cIMT progression in HIV-infected individuals.

CONCLUSIONS

Asian HIV-infected individuals had atherosclerosis progression. Limb fat percentage, LDL cholesterol particle size, and adiponectin level may identify at-risk Asian HIV-infected individuals for early intervention.

Endothelial dysfunction: a unifying hypothesis for the burden of cardiovascular diseases in sub-Saharan Africa

It is well established that the leading causes of death and disability worldwide are cardiovascular diseases (CVD), chief among which is ischaemic heart disease. However, it is also recognised that ischaemic heart disease frequently coexists with other vascular conditions, such as cerebrovascular, renovascular and peripheral vascular disease, thus raising the notion of a common underlying pathobiology, albeit with differing manifestations, dictated by the implicated vascular bed.

The understanding that common metabolic and behavioural risk factors as well as social determinants and drivers are convergent in the development of CVD evokes the idea that the dysfunction of a common bio-molecular platform is central to the occurrence of these diseases. The state of endothelial activation, otherwise known as endothelial dysfunction, occurs when reactive oxygen signalling predominates due to an uncoupled state of endothelial nitric oxide synthase (eNOS). This can be a physiological response to stimulation of the innate immune system or a pathophysiological response triggered by cardiovascular disease risk factors.

The conventional wisdom is that the endothelium plays an important role in the initiation, progression and development of CVD and other non-communicable diseases. Consequently, the endothelium has remarkable relevance in clinical and public health practice as well as in health education, health promotion, and disease- and risk-factor prevention strategies. It also presents a plausible unifying hypothesis for the burden of CVD seen globally and in sub-Saharan Africa. Importantly, the heterogeneity in individual responses to metabolic, behavioural, and social drivers of CVD may stem from a complex interplay of these drivers with genomic, epigenetic and environmental factors that underpin eNOS uncoupling. Therefore, further biomedical research into the underlying genetic and other mechanisms of eNOS uncoupling may enlighten and shape strategies for addressing the burden of CVD in sub-Saharan Africa and other regions of the world.

Mechanisms mediating renal sympathetic nerve activation in obesity-related hypertension

Excessive renal sympathetic nerve activation may be one of the mechanisms underlying obesity-related hypertension. Impaired baroreflex sensitivity, adipokine disorders-such as leptin, adiponectin, and resistin-activation of the renin-angiotensin system, hyperinsulinemia, insulin resistance, and renal sodium retention present in obesity increase renal sympathetic nerve activity, thus contributing to the development of hypertension. Renal sympathetic denervation reduces both renal sympathetic activity and blood pressure in patients with obesity-related hypertension.

Fasting plasma glucose levels predict steroid-induced abnormal glucose metabolism in patients with non-diabetic chronic kidney disease: a prospective cohort study

BACKGROUND/AIMS

Glucocorticoids-induced abnormal glucose metabolism (AGM) is a common medical problem in patients with non-diabetic chronic kidney disease (CKD). However, little information is available regarding the prediction of steroid-induced AGM in this patient population.

METHODS

In this prospective cohort study, we consecutively enrolled 303 non-diabetic CKD patients with fasting plasma glucose (FPG) levels <5.6 mmol/l and normal oral glucose tolerance test (OGTT). OGTT was performed every 3 months during glucocorticoid treatment to identify new-onset AGM, and patients were followed for 12 months post steroid withdrawal.

RESULTS

During 593 person-years, there were 107 incident cases of steroid-induced AGM (18/100 person-year), including 55 (51.4%) diabetes and 52 (48.6%) pre-diabetes. In a multivariate model, each millimole increase per liter in FPG enhanced the risk of AGM by 4.6-fold (hazard ratio 4.58, 95% confidence interval, 2.67-7.83). After adjusting other risk factors, a progressively increased risk of AGM or DM was observed in patients with FPG levels ≥4.8 mmol/l, as compared with those whose levels were ≤4.3 mmol/l (p for trend <0.001). Furthermore, a greater increase in FPG level (≥0.3 mmol/l) during the first 3 months of glucocorticoid treatment was associated with an increased risk for future diabetes. For predicting steroid-induced diabetes, the area under the receiver-operating characteristic curve was 0.90 for the combination of FPG and changes in FPG levels at month 3.

CONCLUSION

Higher-normal FPG and a greater increase in FPG levels during glucocorticoid treatment may help to identify non-diabetic CKD patients at increased risk of steroid-induced AGM or diabetes.

Metabolic syndrome, platelet activation and the development of transient ischemic attack or thromboembolic stroke

Stroke is the second most common cause of mortality in the world today, where transient ischemic attack (TIA) is a period of focal ischemia, the symptoms of which resemble a thromboembolic stroke. Contrary to stroke, TIA symptoms typically last less than one hour and necrosis is absent. Stroke is often preceded by TIA, making it an important predictor of future ischemic events. The causal role of atherosclerosis in the development of TIA is well established, however, research indicates that the atherosclerotic process begins years earlier with the development of metabolic syndrome, which affects approximately 45% of the adult population worldwide. Metabolic syndrome is present if three or more of the following is present: increased waist circumference, increased triglycerides, decreased HDL, increased fasting glucose and hypertension. This syndrome causes systemic inflammation that activates the coagulation system and may cause the formation of pathological thrombi. The role of platelets in stroke has been studied and platelet activation pathways identified. ADP and thromboxane A(2) are the most common activators of platelets in normal physiology. Several pharmacological treatments have been employed to prevent the activation of platelets, the most common of which include aspirin and P2Y(12)-inhibitors. Although treatment is administered strokes and subsequent TIAs are very common in individuals that suffered an initial event. This indicates that research needs to be done in order to elucidate new therapeutic targets, but also to better treat ischemic events to not only decrease the amount of recurring events but also decrease stroke mortality worldwide.

Impact of non-cardiovascular surgery on reactive hyperaemia and arterial endothelial function

Vascular reactivity is a surrogate marker for atherosclerosis and is predictive of cardiovascular outcome. Non-cardiovascular surgery is associated with perioperative cardiovascular complications in high-risk patients. To evaluate the impact of non-cardiovascular surgery on reactive hyperaemia and arterial endothelial function and to investigate the relationships between endothelial dysfunction and invasive (laparotomy) or minimally invasive (laparoscopic) surgery, we prospectively evaluated 106 patients undergoing abdominal surgery under general anaesthesia (71 laparotomy, 35 laparoscopy). Measurements of blood pressure, heart rate and pain (on a visual analogue scale (VAS)) were undertaken. Brachial endothelium-dependent flow-mediated dilation (FMD), endothelium-independent dilation, nitroglycerin (NTG)-induced dilation and reactive hyperaemia were measured with high-resolution B-mode ultrasound on preoperative Day 1 (baseline), as well as 2 h and 1 and 7 days postoperatively. Blood pressure and heart rate were significantly higher 2 h postoperatively. Pain, as measured on the VAS, was higher (P < 0.01) and reactive hyperaemia and FMD were significantly lower (P < 0.001) at 2 h and 1 day postoperatively compared with values at baseline and on postoperative Day 7. By postoperative Day 7, FMD had recovered to baseline levels. Patients undergoing laparoscopic surgery had less FMD reduction on Days 1 and 7 (7.5 ± 1.5% and 7.9 ± 1.5%, respectively) compared with those undergoing laparotomy (6.4 ± 1.6% (P = 0.001) and 7.0 ± 1.6% (P = 0.006), respectively), consistent with potential cardiovascular benefit. Responses to NTG were stable throughout. Backward multivariate linear regression analysis indicated that FMD was independently related to age and VAS (model R = 0.486; F = 6.4; P < 0.001). Reactive hyperaemia and arterial endothelial function are significantly reduced in the early postoperative period, particularly after laparotomy compared with laparoscopy, which may be related to postoperative cardiovascular events.

Fasting glucose level and the risk of incident atherosclerotic cardiovascular diseases

OBJECTIVE

Although diabetes increases the risk of cardiovascular disease (CVD) and mortality, the dose-response relationship between fasting glucose levels below those diagnostic of diabetes with cardiovascular events has not been well characterized.

RESEARCH DESIGN AND METHODS

A prospective cohort study of more than one million Koreans was conducted with a mean follow-up of 16 years. A total of 1,197,384 Korean adults with no specific medical conditions diagnosed were classified by baseline fasting serum glucose level. Associations of fasting glucose level with CVD incidence and mortality, stroke incidence and mortality, and all-cause mortality were analyzed using multivariate proportional hazards regression.

RESULTS

The relationships between fasting glucose levels and CVD risks generally followed J-shape curves, with lowest risk in the glucose range of 85-99 mg/dL. As fasting glucose levels increased to >100 mg/dL, risks for CVD, ischemic heart disease, myocardial infarction, and thrombotic stroke progressively increased, but risk for hemorrhagic stroke did not. Fasting glucose levels <70 mg/dL were associated with increased risk of all stroke (hazard ratio 1.06, 95% CI 1.01-1.11) in men and (hazard ratio 1.11, 1.05-1.17) in women.

CONCLUSIONS

Both low glucose level and impaired fasting glucose should be considered as predictors of risk for stroke and coronary heart disease. The fasting glucose level associated with the lowest cardiovascular risk may be in a narrow range.

Survey of atherosclerotic disease in Asian subjects with cardiovascular disease risk factors who were not receiving lipid-lowering agents

BACKGROUND

Carotid intima media thickness (CIMT) is a surrogate marker for atherosclerosis, used to identify asymptomatic individuals at increased risk of cardiovascular events. The primary objective of this study was to obtain the distribution of CIMT measurements in Asian individuals with cardiovascular disease (CVD) risk factors who were not receiving lipid-lowering agents.

METHODS

Mean CIMT based on ultrasonographic measurement of 12 sites within the common carotid artery was recorded for 2726 subjects across eight Asian countries who had two or more CVD risk factors but were not receiving lipid-lowering therapy. CVD risk factors and lipid and glucose profiles were analyzed with respect to distribution of CIMT and high-sensitivity C-reactive protein (hs-CRP) values.

RESULTS

The overall mean (SD) of mean CIMT (mean-mean CIMT) was 0.662 (0.16) mm. There was a significant variation in mean-mean CIMT across countries (P<0.0001). Mean-mean CIMT values (mm) by age were: 0.485, 0.527, 0.614, 0.665, 0.715 and 0.797 for ≤ 29, 30-39, 40-49, 50-59, 60-69 and ≥ 70 years, respectively. Multivariate analyses confirmed a significant association between increasing mean-mean CIMT and increasing age, male gender, low high-density lipoprotein-cholesterol (HDL-C) levels and elevated fasting blood glucose levels. Analysis of log-transformed hs-CRP levels showed significant association with increasing waist circumference, low-density lipoprotein-cholesterol, body-mass index, high blood glucose levels and low HDL-C.

CONCLUSIONS

Our data show normative mean-mean CIMT data for Asian subjects with two or more CVD risk factors who are not receiving lipid-lowering therapy, which may guide CVD risk-stratification of asymptomatic individuals in Asia.

Cyclooxygenase-2-derived prostanoids reduce inward arterial remodeling induced by blood flow reduction in old obese Zucker rat mesenteric arteries

Obesity is associated with altered arterial structure and function leading to arterial narrowing in most vascular beds, especially when associated with aging. Nevertheless, mesenteric blood flow remains elevated in obese rats, although the effect of aging remains unknown. We investigated mesenteric artery narrowing following blood flow reduction in vivo in 3- and 12-month-old obese Zucker rats. After 21 days, inward remodeling occurred in low flow (LF) arteries in young and old lean rats and in young obese rats (30% diameter reduction). Diameter did not significantly decrease in old obese rats. Phenylephrine-mediated contraction was reduced by approximately 20% in LF arteries in all groups but in old obese rat arteries in which the decrease reached 80%. LF arteries expressed cyclooxygenase-2 and blood 6-keto-PGF1alpha (prostacyclin metabolite) was elevated in old obese rats. In old obese rats, acute cyclooxygenase-2 blockade restored phenylephrine-mediated contraction in LF arteries and chronic cyclooxygenase-2 blockade restored inward remodeling and contractility to control level. Thus, in old obese rats, cyclooxygenase-2-derived prostacyclin prevented the diameter reduction induced by a chronic decrease in blood flow. This adaptation is in favor of a preserved perfusion of the mesentery by contrast with other vascular territories, possibly amplifying the vascular disorders occurring in obesity.

Basal state hyperinsulinemia in healthy normoglycemic adults heralds dysglycemia after more than two decades of follow up

BACKGROUND

In a preliminary report, we found an association between hyperinsulinemia in the basal (fasting) state and the development of diabetes.

OBJECTIVES

The current analysis further explored the long term link between basal hyperinsulinemia and conversion to dysglycemia.

METHODS

This is a prospective study with up to 24 years of follow-up of 515 normoglycemic individuals (mean age at follow up = 70.3 ± 7.0; range 58-94) of an Israeli cohort. Fasting glucose and insulin were measured, and dysglycemia was defined as fasting glucose > 100 mg/dL.

RESULTS

At the end of the follow-up period, almost half had progressed to dysglycemia. Male sex and elevated baseline levels of basal insulin, body mass index, blood glucose and blood pressure each favoured progression to dysglycemia over the subsequent two decades. A multivariate logistic regression model identified basal hyperinsulinemia as the strongest predictor for progression to dysglycemia (odds ratio = 1.79; 95% confidence interval 1.12-2.88), while controlling for ethnicity, blood pressure, fasting glucose, male sex, body mass index and age.

CONCLUSIONS

Basal hyperinsulinemia in normoglycemic adults constitutes an independent risk factor for metabolic deterioration to dysglycemia over adulthood, and may help to identify apparently healthy subjects at increased risk for diabetes.

Obesity and adipokines: effects on sympathetic overactivity

Excess body weight is a major risk factor for cardiovascular disease, increasing the risk of hypertension, hyperglycaemia and dyslipidaemia, recognized as the metabolic syndrome. Adipose tissue acts as an endocrine organ by producing various signalling cytokines called adipokines (including leptin, free fatty acids, tumour necrosis factor-α, interleukin-6, C-reactive protein, angiotensinogen and adiponectin). A chronic dysregulation of certain adipokines can have deleterious effects on insulin signalling. Chronic sympathetic overactivity is also known to be present in central obesity, and recent findings demonstrate the consequence of an elevated sympathetic outflow to organs such as the heart, kidneys and blood vessels. Chronic sympathetic nervous system overactivity can also contribute to a further decline of insulin sensitivity, creating a vicious cycle that may contribute to the development of the metabolic syndrome and hypertension. The cause of this overactivity is not clear, but may be driven by certain adipokines. The purpose of this review is to summarize how obesity, notably central or visceral as observed in the metabolic syndrome, leads to adipokine expression contributing to changes in insulin sensitivity and overactivity of the sympathetic nervous system.

Platelet activation in obesity and metabolic syndrome

Obesity is associated with increased cardiovascular disease. Metabolic syndrome (MS) identifies substantial additional cardiovascular risk beyond the individual risk factors, and is a powerful predictor of cardiovascular events even regardless of body mass index, thus suggesting a common downstream pathway conferring increased cardiovascular risk. Platelet hyper-reactivity/activation plays a central role to accelerate atherothrombosis and is the result of the interaction among the features clustering in obesity and MS: insulin resistance, inflammation, oxidative stress, endothelial dysfunction. Interestingly, the same pathogenic events largely account for the less-than-expected response to antiplatelet agents, namely low-dose aspirin. The proposed explanations for this phenomenon, besides underdosing of drug and/or reduced bioavailability, subsequent to excess of adipose tissue, include enhanced platelet turnover, leading to unacetylated COX-1 and COX-2 in newly formed platelets as a source of aspirin-escaping thromboxane formation; extraplatelet sources of thromboxane, driven by inflammatory triggers; and enhanced lipid peroxidation, activating platelets with a mechanism bypassing COX-1 acetylation or limiting COX-isozyme acetylation by aspirin. This review will address the complex interactions between platelets and the pathogenic events occurring in obesity and MS, trying to translate this body of mechanistic information into a clinically relevant read-out, in order to establish novel strategies in the prevention/treatment of atherothrombosis.

Increased arterial stiffness in healthy subjects with high-normal glucose levels and in subjects with pre-diabetes

BACKGROUND

Increased fasting plasma glucose (FPG), which includes impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes, is a risk factor for arterial stiffness. While IFG is widely accepted as a cardiovascular risk factor, recent studies have argued that subjects with high-normal glucose level were characterized by a high incidence of cardiovascular disease. The purpose of this study is to investigate the relationship between FPG and arterial stiffness in non-diabetic healthy subjects.

METHODS

We recruited 697 subjects who visited the health promotion center of a university hospital from May 2007 to August 2008. Age, sex, body mass index (BMI), resting heart rate, smoking habits, alcohol intake, exercise, blood pressure, medical history, FPG, lipid profile, high sensitivity C-reactive protein (hs-CRP), and Brachial-ankle pulse wave velocity (ba-PWV) were measured. We performed correlation and multiple linear regression analyses to divide the research subjects into quartiles: Q1(n=172), 65 mg/dL≤FPG<84 mg/dL; Q2(n=188), 84 mg/dL≤FPG<91 mg/dl; Q3(n=199), 91 mg/dL≤FPG<100 mg/dL; Q4(n=138), 100 mg/dL≤FPG<126 mg/dL.

RESULTS

FPG has an independent, positive association with ba-PWV in non-diabetic subjects after correcting for confounding variables, including age, sex, BMI, blood pressure, resting heart rate, hs-CRP, lipid profile, and behavioral habits. The mean ba-PWV of the high-normal glucose group (Q3, 1384 cm/s) was higher than that of the low-normal glucose group (1303±196 cm/s vs.1328±167 cm/s, P<0.05). The mean ba-PWV value in the IFG group (1469±220 cm/s) was higher than that in the normoglycemic group (P<0.05, respectively).

CONCLUSIONS

An increase in FPG, even within the normal range, was associated with aggravated arterial stiffness. Further research is needed to determine the glycemic target value for the prevention of arterial stiffness in clinical and public health settings.

Prevalence of prediabetes in patients with metabolic risk

CONTEXT AND OBJECTIVE

Early diagnosis of prediabetes should be done to avoid complications relating to diabetes mellitus (DM). The aim here was to assess the prevalence of prediabetes among individuals at high risk of developing DM, and to seek variables relating to glucose intolerance (GI) among individuals with normal fasting plasma glucose (FPG).

DESIGN AND SETTING

Cross-sectional study at Hospital do Servidor Público Estadual, São Paulo.

METHODS

The FPG and glucose tolerance test (GTT) were analyzed, from which the subjects were divided as follows: group 1 (FPG and GTT both normal), group 2 (normal FPG but abnormal GTT), group 3 (abnormal FPG but normal GTT), and group 4 (FPG and GTT both abnormal). The subjects' clinical, laboratory and anthropometric profile was determined.

RESULTS

138 subjects were studied: 44 in group 1, 11 in group 2, 33 in group 3 and 50 in group 4. The prevalence of prediabetes was 68.0%. Group 4 individuals were older than group 1 individuals [69.0 (55.5-74.0) versus 58.9 ± 11.8 years; P < 0.05], with greater prevalence of risk conditions for DM [5.0 (4.0-5.0) versus 4.0 (3.0-5.0); P < 0.05]. Among individuals with normal FPG, GI prevalence was 20.0%. No variables analyzed correlated with GTT.

CONCLUSION

The prevalence of prediabetes was 68.0%, and 20.0% of subjects with normal FPG had GI. Although some anthropometric, clinical and laboratory variables have been correlated with DM and prediabetes, none, except for GTT, was able to screen for GI among subjects with normal FPG in the present study.

A polymorphism in transforming growth factor-β1 is associated with carotid plaques and increased carotid intima-media thickness in older Chinese men: the Guangzhou Biobank Cohort Study-Cardiovascular Disease Subcohort

OBJECTIVE

Polymorphisms of the transforming growth factor-β1 (TGFB1) gene have not been associated with asymptomatic atherosclerosis previously. We investigated the relationship between a single nucleotide polymorphism (SNP) rs4803455 in TGFB1 and atherosclerosis identified by the presence of carotid plaque and increased intima-media thickness (IMT) in an older Chinese population.

METHODS

1996 subjects (992 (49.7%) men aged 50-85 years) from the Guangzhou Biobank Cohort Study-Cardiovascular Subcohort (GBCS-CVD) were genotyped. Carotid plaque and IMT were assessed by B-mode ultrasonography.

RESULTS

In male subjects, the C allele of TGFB1 rs4803455 was significantly associated with prevalence of carotid plaque (adjusted OR: 2.49, 95% CI: 1.16-5.36, P = 0.03). The C allele was related to increased number of common carotid artery (CCA) plaques (P=0.03) and larger carotid plaque area (P = 0.02) in men. The homozygous carriers of allele C in male subjects also had a higher risk of having carotid IMT ≥ 1 mm (adjusted OR: 1.75, 95% CI: 1.05-2.93, P = 0.03). These associations were independent of age, smoking, physical activity, body mass index, blood pressure, lipid profile, fasting glucose and high sensitivity C-reactive protein.

CONCLUSION

This is the first study to show that the C allele in TGFB1 was associated with increased risk of atherosclerosis in older Chinese men. Further investigations on the linkage between the TGFB1 gene and progression of atherosclerosis in asymptomatic populations are warranted.

High rate of increased carotid intima-media thickness and atherosclerotic plaques in Chinese asymptomatic subjects with central obesity

Both central obesity and increased carotid intima-media thickness (IMT) are markers of atherosclerosis and associated with cardiovascular diseases (CVD). Information of IMT in Chinese subjects with central obesity is limited. This study was performed to assess the rate of atherosclerosis and abnormal IMT in asymptomatic Chinese subjects with central obesity, and to investigate the association between IMT values and CVD risk factors including hypertension, hyperglycaemia and dyslipidaemia. We studied 122 centrally obese adults who had good past health. IMT measurements on carotid arteries were performed and fasting blood taken for plasma glucose and lipid profiles. Abnormal IMT was defined as > 0.9 mm. Atherosclerosis was defined as the presence of one or more visible plague. Of the 122 subjects, the mean (±SD) age was 59.4 ± 5.8 years (median [range]: 59.0 [45-75] years). The median IMT value was 0.70 mm (range: 0.53-1.19 mm) [men vs. women: 0.74 mm vs. 0.66 mm, P-value: < 0.001]. IMT values and the rate of atherosclerosis increased with age and the number of CVD risk factors (P-value for trend: < 0.05). Using binary logistic regression to predict the presence of atherosclerosis with the presence of abnormal IMT, age, gender, and other CVD risk factors as independent variables, age (OR [95% CI] = 1.13 [1.03, 1.23], P = 0.009) and abnormal IMT (OR [95% CI] = 4.05 [1.09, 15.03], P = 0.037) were independently associated with atherosclerosis. In conclusion, among Hong Kong Chinese asymptomatic subjects with central obesity, there was a high rate of CVD risk factors. We found that 19% of these subjects had carotid atherosclerotic plaques and 10% of them had abnormal IMT (>0.9 mm). Carotid IMT study may serve as an appropriate screening tool to diagnose atherosclerosis in the centrally obese middle-aged population.

Mechanisms and significance of progenitor cell reduction in the metabolic syndrome

Bone marrow-derived progenitor cells are involved in the homeostasis of the cardiovascular system through differentiation into endothelium, smooth muscle, and cardiomyocytes. Alterations of these extremely plastic cells have been recognized as both markers of cardiovascular risk and pathophysiological links between risk factors and development of atherosclerosis. Metabolic syndrome, as a cluster of well-defined cardiovascular risk factors, represents a strong predictor of cardiovascular events and death. Moreover, components of the syndrome interact with one another and synergistically increase this risk. Here we describe all metabolic syndrome components as being characterized by alterations in circulating progenitor cells, especially endothelial cells. We also highlight how endothelial progenitors may mediate the interactions between cardiometabolic risk factors in a complex interplay and discuss potential implications for prevention and therapy.

Blood glucose control and coronary heart disease

Epidemiologic data support the hypothesis of a direct and independent relationship between hyperglycemia and cardiovascular disease. The lack of a clear-cut threshold value in diabetic patients, and the persistence of the relationship in nondiabetic population as well, suggest that glycemia is a continuous variable, similarly to other cardiovascular risk factors. Moreover, increased plasma glucose levels contribute to cardiovascular risk by activating multiple atherogenic mechanisms. In spite of evident plausibility for hyperglycemia as a cardiovascular risk factor per se, intervention data remain controversial. Results of recent large-scale intervention trials, such as ACCORD, ADVANCE, and VADT, seem to undermine the concept that tight glycemic control confers some protection against cardiovascular disease in patients with type 2 diabetes, while maintenance of near-normal glycemic control from earlier stage of the disease and during acute coronary events seems to be more beneficial. However, individualized therapies remain the cornerstone of strategies aimed to reduce cardiovascular risk associated to hyperglycemia.

Ultrasound measurement of peripheral endothelial dysfunction in type 2 diabetic patients: correlation with risk factors

The purpose of the study was to assess the endothelial dysfunction (ED) in type 2 diabetic patients ultrasonographically and estimate the correlation of ED with glycemia and other cardio-metabolic risk factors. 171 patient (age 60.0 + 8.5 years) with diagnosed type 2 diabetes and coronary artery disease (CAD) were randomly included in a cross sectional study. B-mode ultrasound system with a linear transducer of 7.5 MHz was used for evaluation of flow-mediated vasodilation in brachial artery (FMV). FMV was presented as a change of brachial artery diameter at rest and after limb ischemia, previously provoked by cuff inflation. Peripheral ED was found in 77.2% (132 patients). Multivariate logistic regression model defined: age (OR 1.071, 95% CI 1.003 1,143) and plasma cholesterol (OR 4.083 95% CI 1.080 17,017) as determinants for ED. Linear multivariate analysis presented duration of diabetes (Beta 0.173, Sig 0.024), and glycemia (Beta 0.132, Sig 0.044) to be associated independently with FMV value. Estimated factors influencing FMV, might be potential therapeutic targets for presented endothelial dysfunction in type 2 diabetic patients with coronary artery disease.

Increased carotid IMT in overweight and obese women affected by Hashimoto's thyroiditis: an adiposity and autoimmune linkage?

BACKGROUND

Hashimoto's thyroiditis is the most important cause of hypothyroidism. It is a systemic disease that can even affect the cardiovascular system, by accelerating the atherosclerotic process. Aim of this study was to examine whether autoimmune thyroiditis has an effect on the intima-media thickness of the common carotid artery (IMT-CCT), independently of the thyroid function and well-known cardiovascular risk factors. Hashimoto's thyroiditis is a systemic disease. The aim is to examine whether autoimmune thyroiditis and adiposity can effect carotid IMT independently of thyroid hormones and cardiovascular risk factors.

METHODS

A total of 104 obese women (BMI > or = 25.0 kg/m-2), with FT3 and FT4 serum levels in the normal range and TSH levels < 4.5 microU/ml, were investigated. None of these patients was taking any kind of drug influencing thyroid function. Measurements were made of the IMT-CCT, BMI, waist circumference, blood pressure levels, as well as fasting TSH, FT3, FT4, anti-thyroid antibodies, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol serum concentrations.

RESULTS

Of the 104 women, 30 (28.8%) were affected by autoimmune thyroiditis. Significantly higher values of IMT-CCT (p < 0.05), TSH (p < 0.05), and triglycerides (p < 0.05) were obtained, and significantly lower values of FT4 (p < 0.05), in patients with Hashimoto's thyroiditis as compared to those with a normal thyroid function. When examining the whole group together, at multiple regression analysis Hashimoto's thyroiditis maintained a positive association with the IMT (p < 0.001), independently of age, hypertension, BMI, and the fasting serum levels of TSH, FT3, FT4, insulin, fasting glycemia, triglycerides, total and HDL-cholesterol levels.

CONCLUSIONS

The present study shows that Hashimoto's thyroiditis is associated to an increased IMT only in overweight and obese, independently of the thyroid function, BMI and cardiovascular risk factors. These results suggest that Hashimoto's thyroiditis is a marker of evolution of the atherosclerosis if combined to adiposity.

Impact of impaired fasting glucose and impaired glucose tolerance on arterial stiffness in an older Chinese population: the Guangzhou Biobank Cohort Study-CVD

The aim of the study was to compare the impact of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) on vascular function among older Chinese people. A random sample of 671 men and 603 women aged 50 to 85 years without known diabetes from the Guangzhou Biobank Study-CVD was examined in a cross-sectional study. Subjects with no previously confirmed or treated diabetes but with both fasting plasma glucose less than 5.6 mmol/L and 2-hour glucose from 7.8 to less than 11.0 mmol/L were classified as having isolated IGT, and those with no previously confirmed and treated diabetes but with both fasting plasma glucose from 5.6 to less than 7.0 mmol/L and 2-hour glucose less than 7.8 mmol/L were classified as having isolated IFG. A total of 11.0% of the men and 8.6% of the women had isolated IFG, and 17.7% of the men and 18.6% of the women had isolated IGT. The brachial-ankle pulse wave velocity and pulse pressure were increased in both the isolated IFG and isolated IGT subjects compared with the normoglycemia group (both Ps < .001). Compared with subjects with isolated IFG, those with isolated IGT appeared to have a higher age- and sex-adjusted brachial-ankle pulse wave velocity (1543 +/- 22 vs 1566 +/- 17, P = .07) and to be more insulin resistant (2-hour postload insulin: 54.2 +/- 2.13 vs 26.8 +/- 2.99 muU/mL, P < .001), had a worse lipid profile (apolipoprotein [apo] B: 1.07 +/- 0.02 vs 0.97 +/- 0.02 g/L, P < .001; apo B/apo A-1 ratio: 0.80 +/- 0.02 vs 0.69 +/- 0.02, P < .001), but had lower glycosylated hemoglobin levels (6.03% +/- 0.06% vs 5.86% +/- 0.04%, P < .001) (values are mean +/- SE). Subjects with isolated IGT had greater arterial stiffness, probably as a result of being more insulin resistant, with a worse lipid profile than those with isolated IFG. The sole use of fasting glucose level to identify prediabetic people would fail to identify a significant proportion of the at-risk population.

Evolving cardiovascular disease prevalence, mortality, risk factors, and the metabolic syndrome in China

The rapid growth transformation of China from a rural agrarian society to an industrial society with increased wealth has impacted the cardiovascular health of the entire population. The increasing prevalence of cardiovascular disease (CVD) and CVD risk factors mirror in some regards the disease prevalence in western industrialized countries and in other areas present unique public health issues. This article reviewed recent population surveys, reports, and clinical trials conducted in China. It was found that the prevalence of CVD and many of the risk factors such as hypertension, obesity, and diabetes contributing to disease mortality are increasing in China. However, compared with the United States, disease mortality is lower. Also, cerebrovascular disease is far more common than ischemic heart disease in China. The low prevalence of disease may suggest a reduced role of diagnostic imaging studies as compared with the US, while the increased percentage of strokes may point to the need for widely available emergent computed tomography (CT) imaging in hospitals in China. This article also discusses the occurrence of metabolic syndrome, obesity, glucose intolerance, diabetes, and their unique features in the Chinese population. Of interest, compared with the Caucasian cohort of the same body mass index (BMI), the Chinese had a higher percentage of body fat. Metabolic syndrome was found to be associated with increased cardiovascular mortality rate. With one fifth of the world's population, China can anticipate a dramatic rise, in absolute numbers, of CVD. It is imperative that national and regional programs are initiated to detect and treat the disease.

An overview of the Guangzhou biobank cohort study-cardiovascular disease subcohort (GBCS-CVD): a platform for multidisciplinary collaboration

The Guangzhou Biobank Cohort Study (GBCS, n=30 519, age >or=50 years) was established to examine the effects of genetic and environmental influences on health problems and chronic disease development. Guangzhou is undergoing massive economic development, but from a baseline that had remained unchanged for millennia. The Cardiovascular Disease Subcohort (GBCS-CVD) consists of 2000 participants who have been intensively phenotyped including a range of surrogate markers of vascular disease, including carotid artery intima-media thickness, cerebral artery stenoses, arterial stiffness, ankle-to-brachial blood pressure index and albuminuria, as well as coagulatory and inflammatory markers. Plasma and leukocytes are stored in liquid nitrogen for future studies. Preliminary demographic data show the female volunteers are younger than the male ones, but present with greater levels of adiposity including central obesity (31 vs 16%). Women had more body fat (33 vs 24%) and associated levels of adipokines. Despite this, body mass index and hip circumferences were similar, which contrasts with Caucasian populations. Men had more physician-diagnosed vascular disease (6.1 vs 2.5%), hypertension (42 vs 34%) and hyperglycaemia (36.6 vs 29.6%) than the women, but were less insulin resistant. In men, smoking (40 vs 2%) and drinking alcohol (67 vs 50%) was more common and they also had lower energy expenditures. The genotype distributions of the 15 typed single nucleotide polymorphisms were all in Hardy-Weinberg equilibrium. This article describes the rationale and methodology for the study. Given the comprehensive characterization of demographic and psychosocial determinants and biochemistry, the study provides a unique platform for multidisciplinary collaboration in a highly dynamic setting.

Hypothyroidism is associated with signs of endothelial dysfunction despite 1-year replacement therapy with levothyroxine

OBJECTIVE

Hypothyroidism is associated with elevated cardiovascular risk, not fully explained by classical risk factors. Instead, endothelial dysfunction may link hypothyroidism to atherosclerosis. The effect of levothyroxine substitution on endothelial function has been sparsely studied and the results are unclear. This study tested endothelial function as estimated by concomitant measurements of endothelial dependent vascular dilatory capacity and plasma concentration of von Willebrand factor antigen in patients with hypothyroidism and further examined the impact of subsequent levothyroxine substitution.

DESIGN AND PATIENTS

Sixteen consecutive patients (13 women, 3 men, aged 46 +/- 11 years) with hypothyroidism were included and compared to 16 matched healthy controls (13 women, 3 men, aged 49 +/- 11 years). Patients with hypothyroidism were reexamined after 3, 6 and 12 months of levothyroxine substitution.

MEASUREMENTS

Dilatory responses of the brachial artery to post-ischaemic increased blood flow (endothelium-dependent flow-associated dilatation) and to nitroglycerin (endothelium-independent nitroglycerin induced dilatation) were measured by ultrasound. Plasma concentrations of von Willebrand factor antigen were measured by ELISA.

RESULTS

Flow-associated dilatation was impaired in patients with hypothyroidism as compared to controls (102.7 +/- 3.6 vs. 105.6 +/- 3.8%, P = 0.04) whereas no differences in plasma concentration of von Willebrand factor antigen were found. One year levothyroxine substitution did not improve flow-associated dilatation and was associated with an increase of the plasma von Willebrand factor antigen concentration.

CONCLUSIONS

Hypothyroid patients are characterized by endothelial dysfunction sustained despite long-term levothyroxine substitution and potentially increasing the risk of atherosclerosis. Different estimates of endothelial dysfunction seem unequally influenced by hypothyroidism.

Endothelial Dysfunction in Patients With Obstructive Sleep Apnoea Independent of Metabolic Syndrome

Introduction: Obstructive sleep apnoea syndrome (OSAS), characterised by intermittent hypoxia/re-oxygenation, has been identified as an independent risk factor for cardiovascular diseases and endothelial dysfunction. Our aim was to investigate flow-mediated dilatation (FMD) in patients with obstructive sleep apnoea with and without metabolic syndrome. Materials and Methods: Fifty-two subjects with OSAS diagnosed by polysomnography were classified into 2 groups according to the presence and absence of the metabolic syndrome and also according to the severity: mild to moderate OSAS group and severe OSAS group. Endothelial function of the brachial artery was evaluated by using high-resolution vascular ultrasound. Endothelial- dependent dilatation (EDD) was assessed by establishing reactive hyperaemia and endothelial- independent dilatation (EID) was determined by using sublingual isosorbide dinitrate. Spearman correlation and regression analysis were performed. Results: EDD was not significantly different in patients with OSAS and metabolic syndrome as compared with OSAS without metabolic syndrome (4.62 ± 0.69 versus 4.49 ± 0.93, P >0.05). Conclusions: Endothelial dysfunction in OSA may be independent of metabolic syndrome. Key words: Endothelial function, Metabolic syndrome, Obstructive sleep apnoea syndrome

Both aerobic endurance and strength training programmes improve cardiovascular health in obese adults

Regular exercise training is recognized as a powerful tool to improve work capacity, endothelial function and the cardiovascular risk profile in obesity, but it is unknown which of high-intensity aerobic exercise, moderate-intensity aerobic exercise or strength training is the optimal mode of exercise. In the present study, a total of 40 subjects were randomized to high-intensity interval aerobic training, continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks, three times/week. The high-intensity group performed aerobic interval walking/running at 85-95% of maximal heart rate, whereas the moderate-intensity group exercised continuously at 60-70% of maximal heart rate; protocols were isocaloric. The strength training group performed 'high-intensity' leg press, abdominal and back strength training. Maximal oxygen uptake and endothelial function improved in all groups; the greatest improvement was observed after high-intensity training, and an equal improvement was observed after moderate-intensity aerobic training and strength training. High-intensity aerobic training and strength training were associated with increased PGC-1alpha (peroxisome-proliferator-activated receptor gamma co-activator 1alpha) levels and improved Ca(2+) transport in the skeletal muscle, whereas only strength training improved antioxidant status. Both strength training and moderate-intensity aerobic training decreased oxidized LDL (low-density lipoprotein) levels. Only aerobic training decreased body weight and diastolic blood pressure. In conclusion, high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function. An important contribution towards improved aerobic work capacity, endothelial function and cardiovascular health originates from strength training, which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform.