Insulin resistance, dietary fat intake and blood pressure predict left ventricular diastolic function 20 years later

Reducing Cardiac Steatosis: Interventions to Improve Diastolic Function - A Narrative Review

Heart failure is one of the main causes of morbidity and mortality around the globe. Heart failure with preserved ejection fraction is primarily caused by diastolic dysfunction. Adipose tissue deposition in the heart has been previously explained in the pathogenesis of diastolic dysfunction. In this article, we aim to discuss the potential interventions that can reduce the risk of diastolic dysfunction by reducing cardiac adipose tissue. A healthy diet with reduced dietary fat content can reduce visceral adiposity and improve diastolic function. Aerobic and resistance exercises also reduce visceral and epicardial fat and ameliorate diastolic dysfunction. Some medications, include metformin, glucagon-like peptide-1 analogues, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, sodium-glucose co-transporter-2, inhibitors, statins, ACE-Is, and ARBs, have shown different degrees of effectiveness in improving cardiac steatosis and diastolic function. Bariatric surgery has also shown promising results in this field.

Triglyceride-Glucose Index and Homeostasis Model Assessment-Insulin Resistance in Young Adulthood and Risk of Incident Congestive Heart Failure in Midlife: The Coronary Artery Risk Development in Young Adults Study

Objective

This study aimed to assess the association between triglyceride-glucose (TyG) index/homeostasis model assessment-insulin resistance (HOMA-IR) within young adults and congestive heart failure (CHF), and to explore whether TyG index can replace HOMA-IR as a surrogate marker for IR in predicting the risk of CHF.

Methods

A total of 4,992 participants between the ages of 18 and 30 years were enrolled from the Coronary Artery Risk Development in Young Adults (CARDIA) investigation [from 1985 to 1986 (year 0)]. A Cox proportional hazard regression analysis was conducted for assessing correlations between baseline TyG index/HOMA-IR and CHF events, together with the receiver operating characteristic (ROC) curve employed for scrutinizing TyG index/HOMA-IR and the risk of CHF.

Results

During the 31-year follow-up period, 64 (1.3%) of the 4,992 participants developed CHF. In multivariable Cox proportional hazards models, adjusted for confounding factors for CHF, an increased risk of CHF was associated with a per-unit increase in the TyG index [hazard ratio (HR) 2.8; 95% confidence interval (CI), 1.7–4.7] and HOMA-IR (HR 1.2; 95% CI, 1.1–1.3). A Kaplan–Meier curve analysis showed that participants in the TyG index and HOMA-IR index Q4 group had a higher risk of CHF than those in the Q1 group. The area under curve (AUC) for the TyG index and HOMA-IR consisted of 0.67 (95% CI, 0.6–0.742) and 0.675 (95% CI, 0.604–0.746), respectively. There were no significant differences between the TyG index and HOMA-IR for AUC (p = 0.986).

Conclusion

The higher TyG index and HOMA-IR are independent risk factors for CHF. The TyG index can replace HOMA-IR in young adulthood as a surrogate marker for IR to predict the risk of CHF.

Association of fasting glucose with lifetime risk of incident heart failure: the Lifetime Risk Pooling Project

BACKGROUND

Given the rising prevalence of dysglycemia and disparities in heart failure (HF) burden, we determined race- and sex-specific lifetime risk of HF across the spectrum of fasting plasma glucose (FPG).

METHODS

Individual-level data from adults without baseline HF was pooled from 6 population-based cohorts. Modified Kaplan-Meier analysis, Cox models adjusted for the competing risk of death, and Irwin's restricted mean were used to estimate the lifetime risk, adjusted hazard ratio (aHR), and years lived free from HF in middle-aged (40-59 years) and older (60-79 years) adults with FPG < 100 mg/dL, prediabetes (FPG 100-125 mg/dL) and diabetes (FPG ≥ 126 mg/dL or on antihyperglycemic agents) across race-sex groups.

RESULTS

In 40,117 participants with 638,910 person-years of follow-up, 4846 cases of incident HF occurred. The lifetime risk of HF was significantly higher among middle-aged White adults and Black women with prediabetes (range: 6.1% [95% CI 4.8%, 7.4%] to 10.8% [95% CI 8.3%, 13.4%]) compared with normoglycemic adults (range: 3.5% [95% CI 3.0%, 4.1%] to 6.5% [95% CI 4.9%, 8.1%]). Middle-aged Black women with diabetes had the highest lifetime risk (32.4% [95% CI 26.0%, 38.7%]) and aHR (4.0 [95% CI 3.0, 5.4]) for HF across race-sex groups. Middle-aged adults with prediabetes and diabetes lived on average 0.9-1.6 and 4.1-6.0 fewer years free from HF, respectively. Findings were similar in older adults except older Black women with prediabetes did not have a higher lifetime risk of HF.

CONCLUSIONS

Prediabetes was associated with higher lifetime risk of HF in middle-aged White adults and Black women, with the association attenuating in older Black women. Black women with diabetes had the highest lifetime risk of HF compared with other race-sex groups.

Lipid profile and left ventricular geometry pattern in obese children

Background

Left ventricular hypertrophy (LVH) is an important risk factor for cardiovascular and all-cause mortality. Previous studies reported conflicting results concerning the relationship between serum lipid levels and left ventricular geometry pattern. We sought to explore the relationship between standard serum lipid profile measures with left ventricular geometry pattern in obese children.

Patients and methods

In this cross-sectional study, a total of 70 obese children were examined. Fasting blood samples were taken to measure total cholesterol, low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides (TGs), glucose, and insulin. Based on these values TG/HDL ratio, BMI and HOMA index were calculated. We also measured the average 24-h ambulatory systolic blood pressure (SBP) and two-dimensional (2/D) transthoracic echocardiography was performed to determine left ventricular mass index (LVMI) and relative wall thickness (RWT). Multiple regression analyses were conducted to explore relationships between study variables and the LVMI or RWT as outcome variables. The final model with LVMI included TG/HDL ratio, BMI, 24 h-average SBP, age and sex, while for the RWT we included BMI, insulin, age and sex.

Results

Our study included 70 children (65.71% boys and 34.29% girls) median age (14 years, IQR = 12–16)." We demonstrated independent and positive association of TG/HDL ratio, BMI and 24 h-average SBP with LVMI (effect = 3.65, SE = 1.32, p < 0.01; effect = 34.90, SE = 6.84, p < 0.01; effect = 0.32, SE = 0.12, p < 0.01, respectively). On the other hand, in model with RWT as outcome variable, only BMI and insulin were significantly linked (BMI: effect = 13.07, SE = 5.02, p = 0.01 Insulin: effect = 2.80, SE = 0.97).

Conclusion

Increased TG/HDL ratio in obese children is associated with the development of eccentric left ventricular hypertrophy while increased BMI and insulin were associated with concentric left ventricular hypertophy.

Type 2 Diabetes Mellitus and Heart Failure: A Scientific Statement From the American Heart Association and the Heart Failure Society of America: This statement does not represent an update of the 2017 ACC/AHA/HFSA heart failure guideline update

Type 2 diabetes mellitus is a risk factor for incident heart failure and increases the risk of morbidity and mortality in patients with established disease. Secular trends in the prevalence of diabetes mellitus and heart failure forecast a growing burden of disease and underscore the need for effective therapeutic strategies. Recent clinical trials have demonstrated the shared pathophysiology between diabetes mellitus and heart failure, the synergistic effect of managing both conditions, and the potential for diabetes mellitus therapies to modulate the risk of heart failure outcomes. This scientific statement on diabetes mellitus and heart failure summarizes the epidemiology, pathophysiology, and impact of diabetes mellitus and its control on outcomes in heart failure; reviews the approach to pharmacological therapy and lifestyle modification in patients with diabetes mellitus and heart failure; highlights the value of multidisciplinary interventions to improve clinical outcomes in this population; and outlines priorities for future research.

Type 2 Diabetes Mellitus and Heart Failure, A Scientific Statement From the American Heart Association and Heart Failure Society of America

Type 2 diabetes mellitus is a risk factor for incident heart failure and increases the risk of morbidity and mortality in patients with established disease. Secular trends in the prevalence of diabetes mellitus and heart failure forecast a growing burden of disease and underscore the need for effective therapeutic strategies. Recent clinical trials have demonstrated the shared pathophysiology between diabetes mellitus and heart failure, the synergistic effect of managing both conditions, and the potential for diabetes mellitus therapies to modulate the risk of heart failure outcomes. This scientific statement on diabetes mellitus and heart failure summarizes the epidemiology, pathophysiology, and impact of diabetes mellitus and its control on outcomes in heart failure; reviews the approach to pharmacological therapy and lifestyle modification in patients with diabetes mellitus and heart failure; highlights the value of multidisciplinary interventions to improve clinical outcomes in this population; and outlines priorities for future research.

Systemic effects of a high saturated fat diet in grizzly bears (Ursus arctos horribilis)

Food sources for North America’s grizzly bear (Ursus arctos horribilis Ord, 1815) population have changed as habitats have fragmented, altering available resources and putting bears in contact with unnatural foods. Bears have evolved mechanisms to tolerate obesity, and do not develop adverse health consequences despite storing massive amounts of body fat. Captive adult grizzly bears were used to determine the effects of dietary fat on health. Group 1 was fed a diet high in polyunsaturated fatty acids (PUFA) wherein 9.5% of available calories came from saturated fatty acids (SFA). Group 2 was fed a diet wherein 28.8% of calories came from SFA. Plasma fatty acids, serum lipid profiles, insulin, inflammatory markers, systolic and diastolic blood pressure, and cardiac function parameters were measured. Serum lipids, SFA, and insulin did not differ between the two groups, although omega-3 fatty acids differed. Bears eating the SFA diet had significantly higher circulating adiponectin, interleukin-7 and interleukin-15, and tumor necrosis factor-alpha. Mild, asymptomatic systolic and diastolic dysfunctions were detected by strain echocardiography in the SFA group. The SFA diet group exhibited higher diastolic arterial pressures. Even though mild metabolic derangements were observed, grizzly bears were remarkably resistant to metabolic effects of diets high in SFA.

Midlife blood pressure predicts future diastolic dysfunction independently of blood pressure

OBJECTIVES

High blood pressure (BP) is associated with diastolic dysfunction, but the consequence of elevated BP over the adult life course on diastolic function is unknown. We hypothesised that high BP in earlier adulthood would be associated with impaired diastolic function independent of current BP.

METHODS

Participants in the Medical Research Council National Survey of Health and Development birth cohort (n=1653) underwent investigations including echocardiography at age 60-64 years. The relationships between adult BP, antihypertensive treatment (HTT) and echocardiographic measures of diastolic function were assessed using adjusted regression models.

RESULTS

Increased systolic BP (SBP) at ages 36, 43 and 53 years was predictive of increased E/e' and increased left atrial volume. These effects were only partially explained by SBP at 60-64 years and increased left ventricular mass. HTT was also associated with poorer diastolic function after adjustment for SBP at 60-64 years. Faster rates of increase in SBP in midlife were also associated with increased poorer diastolic function.

CONCLUSIONS

High SBP in midlife is associated with poorer diastolic function at age 60-64 years. Early identification of individuals with high BP or rapid rises in BP may be important for prevention of impaired cardiac function in later life.

Association of Insulin Resistance and Glycemic Metabolic Abnormalities With LV Structure and Function in Middle Age: The CARDIA Study

OBJECTIVES

This study sought to investigate how cumulative exposure to glycemic abnormalities and trajectories of insulin resistance (IR) relate to left ventricular (LV) remodeling and function during young to middle adulthood.

BACKGROUND

Cumulative exposure to glycemic abnormalities and trajectories of IR may adversely influence LV remodeling and function over a 25-year period in subjects who were young adults, predisposing individuals to heart failure later in life.

METHODS

In the CARDIA (Coronary Artery Risk Development in Young Adults) Year 25 examination, 3,179 participants were identified with information on glucose metabolism; these participants were stratified into 4 subgroups: group 1 normal glucose tolerance (NGT), group 2 impaired glucose tolerance (IGT) or impaired fasting glucose, group 3 late diabetes mellitus (DM) (DM diagnosed at year 15 or later), and group 4 early DM (DM diagnosed at year 0 to year 15). Among the subgroup without DM, 3 trajectory groups of change in the homeostasis model assessment of IR were identified: low IR, moderate IR, and high IR. LV mass, relative wall thickness, LV ejection fraction (LVEF), longitudinal systolic strain (Ell), and early diastolic strain rate (Ell_SRe) at year 25 were assessed by echocardiography. Clinically relevant systolic and diastolic dysfunction were defined as LVEF <50% for systolic dysfunction, and E/e' ≥13 for diastolic dysfunction.

RESULTS

The early DM group had less favorable LV mass (coefficient = 11.04; p < 0.001), LVEF (coefficient = -2.72; p < 0.05), Ell (coefficient = 1.53; p < 0.001), and Ell_SRe (coefficient = -0.09; p < 0.05) than did the NGT group. Being in the early DM group and having high hemoglobin A_1c were independently associated with greater odds of having systolic dysfunction (odds ratio = 5.44; p < 0.005) compared with the NGT group. High IR was associated with worse relative wall thickness (coefficient = 0.019; p < 0.0001) and worse Ell, E', and Ell_SRe, depending on obesity level.

CONCLUSIONS

Cumulative exposure to DM or higher IR beginning in early adulthood adversely impacts LV remodeling and function at middle age.

Ca(2+) mishandling and cardiac dysfunction in obesity and insulin resistance: role of oxidative stress

Obesity and insulin resistance (IR) are strongly connected to the development of subclinical cardiac dysfunction and eventually can lead to heart failure, which is the main cause of morbidity and death in patients having these metabolic diseases. It has been considered that excessive fat tissue may play a critical role in producing systemic IR and enhancing reactive oxygen species (ROS) generation. This oxidative stress (OS) may elicit or exacerbate IR. On the other hand, evidence suggests that some of the cellular mechanisms involved in the pathophysiology of obesity and IR-related cardiomyopathy are excessive myocardial ROS production and abnormal Ca(2+) homeostasis. In addition, emerging evidence suggests that augmented ROS production may contribute to Ca(2+) mishandling by affecting the redox state of key proteins implicated in this process. In this review, we focus on the role of Ca(2+) mishandling in the development of cardiac dysfunction in obesity and IR and address the evidence suggesting that OS might also contribute to cardiac dysfunction by affecting Ca(2+) handling.

Cardiovascular Risk Factors from Early Life Predict Future Adult Cardiac Structural and Functional Abnormalities: A Systematic Review of the Published Literature

Background

Clinical practice evaluates cardiovascular risk based on current risk factor (RF) levels [Blood pressure (BP), body mass index (BMI) and glycaemic control] largely disregarding previous risk-factor history over the totality of the life course. RFs are related to contemporaneous echocardiographic measures of cardiac structure and function which in turn are independently related to cardiovascular morbidity and mortality in cross-sectional studies. However, the effect of lifetime or earlier RF history on future echocardiographic changes has never been systematically examined.

Methods

A systematic review of the published literature identified 24 studies relating either earlier BP, BMI, glycaemic control or a combination to future cardiac structure and/or function.

Results

The majority of studies showed that elevated BP and BMI in earlier life and greater cumulative burden of these factors resulted in worse cardiac structure up to 24 years later. Studies examining glycaemic control as RF were few, but poorer glycaemic control in young adults was associated with increased future left ventricular mass.

While only 5 papers related RFs to future cardiac function, all RFs were positively associated with worse future diastolic function.

Conclusions

BP, BMI and glycaemic control measures in childhood, adolescence and early adulthood and subsequent longitudinal trajectories of BP and BMI are predictive of future abnormalities in cardiac structure and function. Lifetime RF history should be used to inform clinical practice. Further research is required to enable the identification of any sensitive periods in the life course to enable prevention when it is most likely to be effective.

Heart failure in North America

Heart failure is a major health problem that affects patients and healthcare systems worldwide. Within the continent of North America, differences in economic development, genetic susceptibility, cultural practices, and trends in risk factors and treatment all contribute to both inter-continental and within-continent differences in heart failure. The United States and Canada represent industrialized countries with similar culture, geography, and advanced economies and infrastructure. During the epidemiologic transition from rural to industrial in countries such as the United States and Canada, nutritional deficiencies and infectious diseases made way for degenerative diseases such as cardiovascular diseases, cancer, overweight/obesity, and diabetes. This in turn has resulted in an increase in heart failure incidence in these countries, especially as overall life expectancy increases. Mexico, on the other hand, has a less developed economy and infrastructure, and has a wide distribution in the level of urbanization as it becomes more industrialized. Mexico is under a period of epidemiologic transition and the etiology and incidence of heart failure is rapidly changing. Ethnic differences within the populations of the United States and Canada highlight the changing demographics of each country as well as potential disparities in heart failure care. Heart failure with preserved ejection fraction makes up approximately half of all hospital admissions throughout North America; however, important differences in demographics and etiology exist between countries. Similarly, acute heart failure etiology, severity, and management differ between countries in North America. The overall economic burden of heart failure continues to be large and growing worldwide, with each country managing this burden differently. Understanding the inter-and within-continental differences may help improve understanding of the heart failure epidemic, and may aid healthcare systems in delivering better heart failure prevention and treatment.

Serum β-carotene concentrations and the risk of congestive heart failure in men: a population-based study

BACKGROUND

Fruit and vegetable intake has been associated with lower risk for cardiovascular diseases, but data on congestive heart failure (CHF) are inconsistent. The association of serum carotenoids, biomarkers reflecting fruit and vegetable intake, with the risk of CHF has not been well documented in previous studies. We therefore examined the association between carotenoid levels and the risk of CHF.

METHODS

Data were available for 1031 males aged 46 to 65 years participating in the Kuopio Ischaemic Heart Disease Risk Factor Study (Finland). Baseline data for the present study were collected between 1991 and 1993. The association between serum concentrations of carotenoids and the risk of CHF was examined by using Cox proportional hazard models.

RESULTS

During the median of 17.8 follow-up years, CHF occurred in 72 patients. Age and examination year adjusted risk (hazard ratio, HR) for CHF among men within the lowest quartile of serum β-carotene was 4.08 (95% CI, 1.90-8.78, p<0.001) as compared to men in the highest quartile of serum β-carotene. After further adjustment for many potential confounders, men with the lowest quartile of β-carotene had almost 3-fold increased risk of CHF (HR=2.78, 95% CI, 1.23-6.25, p=0.014). However, serum concentrations of lycopene and α-carotene were not related to the risk of CHF.

CONCLUSIONS

The present study suggests that low concentrations of serum β-carotene may be associated with an increased risk of CHF.

Plasma phospholipid fatty acid composition and estimated desaturase activity in heart failure patients with metabolic syndrome

Metabolic syndrome is one of the major factors to increase the incidence of heart failure. In our study, we compared plasma fatty acid compositions among heart failure patients with and without Metabolic syndrome. Fatty acid (FA) composition of plasma phospholipids was analyzed and the activities of desaturase were estimated as the ratio of substrate and product fatty acids in 85 stable heart failure patients. Fatty acid and estimated desaturase activities were further examined for their associations with Metabolic syndrome components. Heart failure patients with Metabolic syndrome showed significant changes in fatty acid composition in comparison to those without Metabolic syndrome, which had a decreased proportion of lauric acid (C12:0) and an increased proportion of dihomo-γ-linolenic acid (C20:3n-6). Also, estimated desaturase activities (D5D and D6D) were closely related to Metabolic syndrome condition among heart failure patients. The content of dihomo-γ-linolenic acid showed positive correlations with BMI, waist circumference, and plasma triglyceride levels. D6D were positively associated with plasma triglyceride levels, whereas D5D showed a negative correlation with plasma triglyceride levels and waist circumferences. The content of dihomo-γ-linolenic acid as well as estimated D6D and D5D were altered in heart failure patients with Metabolic syndrome.

Increased heart failure risk in normal-weight people with metabolic syndrome compared with metabolically healthy obese individuals

OBJECTIVES

The purpose of this study was to assess whether the metabolically healthy obese phenotype is associated with lower heart failure (HF) risk compared with normal-weight individuals with metabolic syndrome (MetS).

BACKGROUND

Obesity and MetS often coexist and are associated with increased HF risk. It is controversial whether obese individuals with normal insulin sensitivity have decreased HF risk.

METHODS

A total of 550 individuals without diabetes or baseline macrovascular complications were studied during a median follow-up of 6 years. Participants were classified by presence (n = 271) or absence (n = 279) of MetS and by body mass index (body mass index: <25 kg/m(2) = normal weight, n = 177; 25 to 29.9 kg/m(2) = overweight, n = 234; ≥ 30 kg/m(2) = obese, n = 139). MetS was diagnosed with the National Cholesterol Education Program Adult Treatment Panel III criteria. Left ventricular functional capacity, myocardial structure, and performance were assessed echocardiographically.

RESULTS

Body mass index was not associated with increased HF risk. The presence of MetS conferred a 2.5-fold higher HF risk (hazard ratio [HR]: 2.5, 95% confidence interval [CI]: 1.68 to 3.40). Overweight and obese individuals without MetS had the lowest 6-year HF risk (HR: 1.12, 95% CI: 0.35 to 1.33 [corrected] and HR: 0.41, 95% CI: 0.10 to 1.31, respectively) compared with normal-weight individuals with MetS (HR: 2.33, 95% CI: 1.25 to 4.36, p < 0.001). From the individual components of MetS, impaired fasting glucose (HR: 1.09, 95% CI: 1.06 to 1.10), high BP (HR: 2.36, 95% CI: 1.03 to 5.43), low high-density lipoprotein cholesterol (HR: 1.88, 95% CI: 1.29 to -2.77), and central obesity (HR: 2.22, 95% CI: 1.02 to 1.05) were all associated with increased HF risk. Factors commonly associated with MetS such as insulin resistance and inflammation (high-sensitivity C-reactive protein and microalbuminuria) were also independently associated with HF incidence.

CONCLUSIONS

In contrast to normal weight insulin-resistant individuals, metabolically healthy obese individuals show decreased HF risk in a 6-year follow-up study.

Heart rate is associated with red blood cell fatty acid concentration: the Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) study

BACKGROUND

Consumption of omega-3 fatty acids (FAs) is associated with a reduction in deaths from coronary heart disease, arrhythmia, and sudden death. Although these FAs were originally thought to be antiatherosclerotic, recent evidence suggests that their benefits are related to reducing risk for ventricular arrhythmia and that this may be mediated by a slowed heart rate (HR).

METHODS

The study was conducted in Alaskan Eskimos participating in the Genetics of Coronary Artery Disease in Alaska Natives (GOCADAN) Study, a population experiencing a dietary shift from unsaturated to saturated fats. We compared HR with red blood cell (RBC) FA content in 316 men and 391 women ages 35 to 74 years.

RESULTS

Multivariate linear regression analyses of individual FAs with HR as the dependent variable and specific FAs as covariates revealed negative associations between HR and docosahexaenoic acid (22:6n-3; P = .004) and eicosapentaenoic acid (20:5n-3; P = .009) and positive associations between HR and palmitoleic acid (16:1n-7; P = .021), eicosanoic acid (20:1n9; P = .007), and dihomo-gamma-linolenic acid (DGLA; 20:3n-6; P = .021). Factor analysis revealed that the omega-3 FAs were negatively associated with HR (P = .003), whereas a cluster of other, non-omega-3 unsaturated FAs (16:1, 20:1, and 20:3) was positively associated.

CONCLUSIONS

Marine omega-3 FAs are associated with lower HR, whereas palmitoleic and DGLA, previously identified as associated with saturated FA consumption and directly related to cardiovascular mortality, are associated with higher HR. These relations may at least partially explain the relations between omega-3 FAs, ventricular arrhythmia, and sudden death.

Glucose, obesity, metabolic syndrome, and diabetes relevance to incidence of heart failure

Heart failure (HF) is common, results in poor clinical outcomes, and is associated with large health care costs. The incidence of HF continues to rise, with approximately 670,000 new cases per year and a 20% lifetime risk of HF for persons 40 years and older in the U.S. Risk factors for HF have been identified, and thus preventative strategies should have a positive effect on disease burden, morbidity, and mortality. Although coronary artery disease and hypertension have traditionally been considered among the most important modifiable risk factors for the development of HF, recent studies have highlighted the importance of increasingly prevalent metabolic risk factors: glucose, diabetes, obesity, and the metabolic syndrome. This report will present evidence for the link between glucose, diabetes, obesity, metabolic syndrome, and incident HF. Furthermore, we will discuss how risk factor modification and other preventive therapies may help curb the rising incidence of HF.

The PPARGC1A Gly482Ser polymorphism is associated with left ventricular diastolic dysfunction in men

Background

The Gly482Ser polymorphism in peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PPARGC1A) has been demonstrated to be associated with diabetes, obesity and hypertension, all of which are important risk factors for left ventricular diastolic dysfunction.

Methods

The PPARGC1A Gly482Ser polymorphism was genotyped in a community-based cohort of 499 men and 533 women, who also underwent an echocardiographic examination to determine their left ventricular diastolic function. The association between the polymorphism and the presence of diastolic dysfunction was evaluated using logistic regression models.

Results

The Ser allele of the PPARGC1A Gly482Ser polymorphism was significantly associated with a lower risk of diastolic dysfunction in men, but not in women. In a model adjusting for potential confounders (age, body mass index, leisure time physical activity, hypertension and diabetes) the results were still significant and substantial (odds ratio 0.13, 95% confidence interval 0.03–0.54, p for trend = 0.004). The results were consistent in a series of models, and they imply a multiplicative, protective effect of the Ser allele, with lower risk of diastolic dysfunction for each copy of the allele.

Conclusion

The Ser allele of the PPARGC1A Gly482Ser polymorphism was associated with decreased risk of diastolic left ventricular dysfunction in men, but not in women, in our large community-based sample. It was associated with a substantially decreased risk, even after adjustment for potential confounders. The clinical importance of the findings has to be established in further studies.

Increased cardiovascular events in hypertensive patients with insulin resistance: a 13-year follow-up

Insulin resistance (IR) is commonly associated with other cardiovascular risk factors and is considered an independent risk factor for cardiovascular disease and events. The hyperinsulinemic euglycemic clamp technique is considered the gold standard for evaluating IR, but this technique is cumbersome and not easily applicable in large studies. Therefore, there are no long-term follow-up published studies on the relationship between IR determined by this technique and cardiovascular outcome. Thirteen years ago we performed a hyperinsulinemic euglycemic clamp in 31 hypertensive patients, 16 of whom manifested IR and 15 had normal insulin sensitivity. Thirteen years later we were able to re-evaluate or obtain medical records for all these patients. Over these years, 11 of the 16 insulin resistant patients developed cardiovascular disease and events, including two cardiovascular deaths, two myocardial infarctions, one angina pectoris, one peripheral vascular disease, and five carotid plaques or stenosis. Moreover, two patients developed new onset diabetes, one proteinuria and two impaired kidney function. Among insulin-sensitive patients, one developed peripheral vascular disease, one new onset diabetes and one proteinuria. In conclusion, this is the first longitudinal study of the relationship between insulin resistance, measured by the hyperinsulinemic euglycemic clamp and cardiovascular disease and events in a small cohort of patients with essential hypertension. The data suggest that hypertensive patients with IR are at greater risk of developing cardiovascular disease and events than hypertensive patients with normal insulin sensitivity.

Metabolic syndrome and risk for heart failure in middle-aged men

OBJECTIVE

To explore metabolic syndrome as a possible risk factor for development of heart failure (HF).

DESIGN

Community-based cohort study.

SETTING

Uppsala, Sweden.

PARTICIPANTS

2314 50-year-old men free from HF, myocardial infarction and valvular disease at baseline were enrolled between 1970 and 1974 and were followed up until the age of 70. A modified National Cholesterol Education Program definition of metabolic syndrome was used with body mass index in the place of waist circumference.

MAIN OUTCOME MEASURE

First hospitalisation for HF.

RESULTS

In multivariable Cox proportional hazards models adjusted for established risk factors for HF (hypertension, diabetes, ECG left ventricular hypertrophy, smoking and body mass index), the presence at baseline of metabolic syndrome (hazard ratio 1.66, 95% confidence interval (CI) 1.02 to 2.70) was a predictor of subsequent HF. This relation was even stronger after adjustment for the presence of an acute myocardial infarction during follow up in addition to the other established risk factors for HF (hazard ratio 1.80, 95% CI 1.11 to 2.91).

CONCLUSION

Metabolic syndrome was a significant predictor of HF, independent of established risk factors for HF including an interim myocardial infarction, during two decades of follow up in a community-based sample of middle-aged men. This implies that metabolic syndrome provides important risk information beyond that of established risk factors for HF.

Novel metabolic risk factors for heart failure

OBJECTIVES

Our objectives were to explore novel metabolic risk factors for development of heart failure (HF).

BACKGROUND

In the past decade, considerable knowledge has been gained from limited samples regarding novel risk factors for HF, but the importance of these in the general population is largely unexplored.

METHODS

In a community-based prospective study of 2,321 middle-aged men free from HF and valvular disease at baseline, variables reflecting glucose and lipid metabolism and variables involved in oxidative processes were compared with established risk factors for HF (prior myocardial infarction, hypertension, diabetes, electrocardiographic left ventricular hypertrophy, smoking, obesity, and serum cholesterol) using Cox proportional hazards analyses.

RESULTS

During a median follow-up time of 29 years, 259 subjects developed HF. In a multivariable Cox proportional hazards backward stepwise model, a 1-SD increase of fasting proinsulin (hazard ratio [HR] 1.38, 95% confidence interval [CI] 1.15 to 1.66) and apolipoprotein B/A-I-ratio (HR 1.27, 95% CI 1.09 to 1.48) increased the risk, whereas a 1-SD increase in serum beta-carotene (HR 0.79, 95% CI 0.66 to 0.94) decreased the risk of HF. These variables also remained significant when adjusting for acute myocardial infarction during follow-up.

CONCLUSIONS

Novel variables reflecting insulin resistance and dyslipidemia, together with a low beta-carotene level, were found to predict HF independently of established risk factors. If confirmed, our observations could have large clinical implications, as they may offer new approaches in the prevention of HF.

hUNC-93B1, a novel gene mainly expressed in the heart, is related to left ventricular diastolic function, heart failure morbidity and mortality in elderly men

AIMS

The hUNC-93B1 gene has the highest expression in the heart. We aimed to explore relationships between the hUNC-93B1 gene and cardiac function, morbidity and mortality in elderly men.

METHODS AND RESULTS

Two sub-samples of the population-based ULSAM-cohort (n=330, mean age 71 years and n=152, mean age 75 years, respectively) were used to explore and validate relationships between genotypes of the hUNC-93B1 gene and cardiac phenotypes (ejection fraction, E/A-ratio, left ventricular mass index and relative wall thickness). In the two samples, subjects homozygous for haplotype H3 had 34% and 35% higher level of E/A-ratio compared to non-carriers (p=0.0002 and 0.017, respectively) independent of cardiovascular disease and medication. Using national cause-of-death and hospital-discharge register data with 29 years of follow-up, no heart failure patients homozygous for haplotype H3 were hospitalised for heart failure before the age of 75 years, compared to 25% for heterozygous and 55% for non-carriers (p<0.03). No homozygous subjects died during follow-up while 17% of the heterozygous and 15% of the non-carriers died (p=0.01).

CONCLUSION

Haplotype H3 of the hUNC-93B1 gene seems related to E/A-ratio in elderly men. The relationship between the hUNC-93B1 gene and the age at onset of heart failure and mortality support a view of a clinically relevant impact of the gene.