Nutritional regulation of adipose tissue lipoprotein lipase is blunted in insulin resistant rats

Background  

Hypertriglyceridemia is a common lipid abnormality accompanying insulin resistance. This study was designed to assess the contribution of dysregulation of adipose tissue lipoprotein lipase (LPL) activity to the hypertriglyceridemia in a rat model of insulin resistance.     

The comparison of insulin and uric acid levels in adolescents with and without metabolic syndrome

Background and Aim

The prevalence of metabolic syndrome (MS) increased in recent years in both adolescents and children groups. The aim of the study is evaluating the relationship between insulin and uric acid (UA) level in MS in adolescents

Materials and Methods

we studied 120 adolescence aged 10 to 19 in two groups: control group without metabolic syndrome and case group with metabolic syndrome. The Criteria of ATP III was considered as a diagnosis factor for metabolic syndrome.

Discussion

Various studies have been conducted in various populations to evaluate the relationship between UA level and MS in adolescents. Abdominal obesity, low HDL, hypertriglyceridemia and hypertension are associated with high UA level. In their analysis, the MS OR in UA level?4.9, 4.9-5.8 and ?5.8 mg/dl was 1, 2.53 and 9.03, respectively, which were higher than our findings in current study. Hyperinsulinemia caused by insulin resistance is one of the complications associated with MS, which puts individuals at risk of diabetes and cardiovascular events.

Results

Uric acid level in the Case group was significantly higher than the control group (p = 0.0001, 43.8±1.4 vs. 4.1±1 mg/dl, respectively). Insulin level was significantly higher in the case group in compare to the control group (p = 0.008, 9.8± 5.3 vs. 12.2±6 μU/ml, respectively).

Conclusion

The findings of this case-control study showed that adolescents with metabolic syndrome have a higher uric acid and insulin level in compare to normal subjects. We hypothesis that increase in serum insulin and uric acid level can be a risk factor in the development of metabolic syndrome.

     

Glycated Hemoglobin,Fasting Insulin and the Metabolic Syndrome in Males. Cross-Sectional Analyses of the Aragon Workers’ Health Study Baseline

Background and Aims

Glycated hemoglobin (HbA1c) is currently used to diagnose diabetes mellitus, while insulin has been relegated to research. Both, however, may help understanding the metabolic syndrome and profiling patients. We examined the association of HbA1c and fasting insulin with clustering of metabolic syndrome criteria and insulin resistance as two essential characteristics of the metabolic syndrome.

Methods

We used baseline data from 3200 non-diabetic male participants in the Aragon Workers'' Health Study. We conducted analysis to estimate age-adjusted odds ratios (ORs) across tertiles of HbA1c and insulin. Fasting glucose and Homeostatic model assessment - Insulin Resistance were used as reference. Here we report the uppermost-to-lowest tertile ORs (95%CI).

Results

Mean age (SD) was 48.5 (8.8) years and 23% of participants had metabolic syndrome. The ORs for metabolic syndrome criteria tended to be higher across HbA1c than across glucose, except for high blood pressure. Insulin was associated with the criteria more strongly than HbA1c and similarly to Homeostatic model assessment - Insulin Resistance (HOMA-IR). For metabolic syndrome, the OR of HbA1c was 2.68, of insulin, 11.36, of glucose, 7.03, and of HOMA-IR, 14.40. For the clustering of 2 or more non-glycemic criteria, the OR of HbA1c was 2.10, of insulin, 8.94, of glucose, 1.73, and of HOMA-IR, 7.83. All ORs were statistically significant. The areas under the receiver operating characteristics curves for metabolic syndrome were 0.670 (across HbA1c values) and 0.770 (across insulin values), and, for insulin resistance, 0.647 (HbA1c) and 0.995 (insulin). Among non-metabolic syndrome patients, a small insulin elevation identified risk factor clustering.

Conclusions

HbA1c and specially insulin levels were associated with metabolic syndrome criteria, their clustering, and insulin resistance. Insulin could provide early information in subjects prone to develop metabolic syndrome.     

Rats with steroid-induced polycystic ovaries develop hypertension and increased sympathetic nervous system activity

Background  

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder associated with ovulatory dysfunction, abdominal obesity, hyperandrogenism, hypertension, and insulin resistance.     

Hyperandrogenemia in Polycystic Ovary Syndrome: Exploration of the Role of Free Testosterone and Androstenedione in Metabolic Phenotype

Objective

To evaluate the association between androstenedione, testosterone, and free testosterone and metabolic disturbances in polycystic ovary syndrome.

Methods

We analyzed the association between androstenedione, testosterone, and free testosterone and metabolic parameters in a cross-sectional study including 706 polycystic ovary syndrome and 140 BMI-matched healthy women. Polycystic ovary syndrome women were categorized into 4 groups: normal androstenedione and normal free testosterone (NA/NFT), elevated androstenedione and normal free testosterone (HA/NFT), normal androstenedione and elevated free testosterone (NA/HFT), elevated androstenedione and free testosterone (HA/HFT).

Results

Polycystic ovary syndrome women with elevated free testosterone levels (HA/HFT and NA/HFT) have an adverse metabolic profile including 2 h glucose, HbA1c, fasting and 2 h insulin, area under the insulin response curve, insulin resistance, insulin sensitivity index (Matsuda), triglycerides, total and high density lipoprotein cholesterol levels compared to NA/NFT (p<0.05 for all age- and BMI-adjusted analyses). In binary logistic regression analysis adjusted for age and BMI, odds ratio for insulin resistance was 2.78 (1.34–5.75, p = 0.006) for polycystic ovary syndrome women with HA/HFT compared to NA/NFT. We found no significantly increased risk of metabolic disorders in polycystic ovary syndrome women with HA/NFT. In multiple linear regression analyses (age- and BMI-adjusted), we found a significant negative association between androstenedione/free testosterone-ratio and area under the insulin response curve, insulin resistance, and total cholesterol/high density lipoprotein cholesterol-ratio and a positive association with Matsuda-index, and high density lipoprotein cholesterol (p<0.05 for all).

Conclusions

Polycystic ovary syndrome women with elevated free testosterone levels but not with isolated androstenedione elevation have an adverse metabolic phenotype. Further, a higher androstenedione/free testosterone-ratio was independently associated with a beneficial metabolic profile.     

Post-streptococcal antibodies are associated with metabolic syndrome in a population-based cohort

Background

Streptococcal infections are known to trigger autoimmune disorders, affecting millions worldwide. Recently, we found an association between post-streptococcal autoantibodies against Protein Disulphide Isomerase (PDI), an enzyme involved in insulin degradation and insulin resistance. This led us to evaluate associations between post-streptococcal antibodies and metabolic syndrome, as defined by the updated National Cholesterol Education Program definition, 2005.

Methods and Findings

Metabolic data (HDL, triglycerides, fasting glucose, blood pressure, waist circumference, BMI, smoking), post-streptococcal antibodies (anti-Streptolysin O (ASO) and anti-PDI), and C-reactive protein (CRP, as a general inflammatory marker), were assessed in 1156 participants of the Wisconsin Sleep Cohort Study. Anti-PDI antibodies were found in 308 participants (26.6%), ASO≥100 in 258 (22.3%), and 482 (41.7%) met diagnostic criteria for metabolic syndrome. Anti-PDI antibodies but not ASO were significantly associated with metabolic syndrome [n = 1156, OR 1.463 (95% CI 1.114, 1.920), p = 0.0062; adjusted for age, gender, education, smoking]. Importantly, the anti-PDI - metabolic syndrome association remained significant after adjusting for CRP and fasting insulin.

Conclusions

Post-streptococcal anti-PDI antibodies are associated with metabolic syndrome regardless of fasting insulin and CRP levels. Whereas these data are in line with a growing body of evidence linking infections, immunity and metabolism, additional studies are necessary to establish the post-streptococcal – metabolic syndrome association.     

Relationships among Smoking Habits,Airflow Limitations,and Metabolic Abnormalities in School Workers

Background

Chronic obstructive pulmonary disease is caused mainly by habitual smoking and is common among elderly individuals. It involves not only airflow limitation but also metabolic disorders, leading to increased cardiovascular morbidity and mortality.

Objective

We evaluated relationships among smoking habits, airflow limitation, and metabolic abnormalities.

Methods

Between 2001 and 2008, 15,324 school workers (9700 males, 5624 females; age: ≥30 years) underwent medical checkups, including blood tests and spirometry. They also responded to a questionnaire on smoking habits and medical history.

Results

Airflow limitation was more prevalent in current smokers than in ex-smokers and never-smokers in men and women. The frequency of hypertriglyceridemia was higher in current smokers in all age groups, and those of low high-density-lipoprotein cholesterolemia and diabetes mellitus were higher in current smokers in age groups ≥ 40 s in men, but not in women. There were significant differences in the frequencies of metabolic abnormalities between subjects with airflow limitations and those without in women, but not in men. Smoking index was an independent factor associated with increased frequencies of hypertriglyceridemia (OR 1.015; 95% CI: 1.012–1.018; p<0.0001) and low high-density-lipoprotein cholesterolemia (1.013; 1.010–1.016; p<0.0001) in men. Length of smoking cessation was an independent factor associated with a decreased frequency of hypertriglyceridemia (0.984; 0.975–0.994; p = 0.007).

Conclusions

Habitual smoking causes high incidences of airflow limitation and metabolic abnormalities. Women, but not men, with airflow limitation had higher frequencies of metabolic abnormalities.     

Work-Related Psychological Injury Is Associated with Metabolic Syndrome Components in Apparently Healthy Workers

Objective

The aim of this study was to evaluate the association between psychological damage caused by common occupational trauma and metabolic syndrome (MES).

Method

571 workers from 20 small Italian companies were invited to fill in the Psychological Injury Risk Indicator (PIRI) during their routine medical examination at the workplace.

Results

Compared to workers with no psychological injury, workers with a high PIRI score had a significantly increased risk of having at least one metabolic syndrome component (adjusted hazards ratio, 1.8; 95% confidence interval, 1.2 to 2.6). There was a significant increase in the risk of hypertriglyceridemia in male workers (OR 2.53 CI95% 1.03-6.22), and of hypertension in female workers (OR 2.45 CI95% 1.29-4.66).

Conclusion

Psychological injury related to common occupational trauma may be a modifiable risk factor for metabolic syndrome.     

Serum Liver Fatty Acid Binding Protein Levels Correlate Positively with Obesity and Insulin Resistance in Chinese Young Adults

Background

Liver fatty acid–binding protein (FABP1) plays an inconclusive role in adiposity. We investigated the association of serum FABP1 levels with obesity and insulin resistance in Chinese young people under 30 years old.

Methodology and Principal Findings

Cross-sectional analysis including 200 obese and 172 normal-weight subjects matched for age and sex, anthropometric measurements were performed and serum FABP1 and biochemical characteristics were measured. Insulin resistance was determined by homeostasis model assessment of insulin resistance (HOMA-IR) and by the insulin sensitivity index (S_i) derived from Bergman’s minimal model. FABP1 levels in obese subjects were significantly higher than those in normal-weight subjects (p<0.001) and the significance remained after adjustment for age, gender, alanine and aspartate aminotransferases (p<0.001). Serum FABP1 levels were significantly correlated with many metabolic-related parameters, with BMI and triglycerides as the independent determinants. FABP1 levels remained an independent risk factor of insulin resistance assessed by binary S_i (OR = 1.868 per SD unit, 95% CI [1.035–3.373], p = 0.038) after adjustment for age, sex, BMI, waist circumference, systolic blood pressure, serum triacylglycerol, total cholesterol, HDL- and LDL-cholesterol,. FABP1 levels were also elevated with an increasing number of components of the metabolic syndrome (p for trend <0.001). Multiple regression modeling for the MetS and its components demonstrated that hypertriglyceridemia and low HDL-cholesterol were significantly correlated to serum FABP1 levels.

Conclusions and Significance

Serum FABP1 correlates positively with obesity and insulin resistance in Chinese young adults. Our data supports the fact that FABP1 might be an important mediator participating in fatty acid metabolism and energy balance.     

Metabolic effect of telmisartan and losartan in hypertensive patients with metabolic syndrome

Background

Metabolic syndrome is a cluster of common cardiovascular risk factors that includes hypertension and insulin resistance. Hypertension and diabetes mellitus are frequent comorbidities and, like metabolic syndrome, increase the risk of cardiovascular events. Telmisartan, an antihypertensive agent with evidence of partial peroxisome proliferator-activated receptor activity-gamma (PPARγ) activity, may improve insulin sensitivity and lipid profile in patients with metabolic syndrome.

Methods

In a double-blind, parallel-group, randomized study, patients with World Health Organization criteria for metabolic syndrome received once-daily doses of telmisartan (80 mg, n = 20) or losartan (50 mg, n = 20) for 3 months. At baseline and end of treatment, fasting and postprandial plasma glucose, insulin sensitivity, glycosylated haemoglobin (HBA_1c) and 24-hour mean systolic and diastolic blood pressures were determined.

Results

Telmisartan, but not losartan, significantly (p < 0.05) reduced free plasma glucose, free plasma insulin, homeostasis model assessment of insulin resistance and HbA_ic. Following treatment, plasma glucose and insulin were reduced during the oral glucose tolerance test by telmisartan, but not by losartan. Telmisartan also significantly reduced 24-hour mean systolic blood pressure (p < 0.05) and diastolic blood pressure (p < 0.05) compared with losartan.

Conclusion

As well as providing superior 24-hour blood pressure control, telmisartan, unlike losartan, displayed insulin-sensitizing activity, which may be explained by its partial PPARγ activity.     

Validation of endogenous reference genes for qRT-PCR analysis of human visceral adipose samples

Background  

Given the epidemic proportions of obesity worldwide and the concurrent prevalence of metabolic syndrome, there is an urgent need for better understanding the underlying mechanisms of metabolic syndrome, in particular, the gene expression differences which may participate in obesity, insulin resistance and the associated series of chronic liver conditions. Real-time PCR (qRT-PCR) is the standard method for studying changes in relative gene expression in different tissues and experimental conditions. However, variations in amount of starting material, enzymatic efficiency and presence of inhibitors can lead to quantification errors. Hence the need for accurate data normalization is vital. Among several known strategies for data normalization, the use of reference genes as an internal control is the most common approach. Recent studies have shown that both obesity and presence of insulin resistance influence an expression of commonly used reference genes in omental fat. In this study we validated candidate reference genes suitable for qRT-PCR profiling experiments using visceral adipose samples from obese and lean individuals.     

Increased prevalence of metabolic syndrome in patients with acne inversa

Background

Acne inversa (AI; also designated as Hidradenitis suppurativa) is a common chronic inflammatory skin disease, localized in the axillary, inguinal and perianal skin areas that causes painful, fistulating sinuses with malodorous purulence and scars. Several chronic inflammatory diseases are associated with the metabolic syndrome and its consequences including arteriosclerosis, coronary heart disease, myocardial infraction, and stroke. So far, the association of AI with systemic metabolic alterations is largely unexplored.

Methods and Findings

A hospital-based case-control study in 80 AI patients and 100 age- and sex-matched control participants was carried out. The prevalence of central obesity (odds ratio 5.88), hypertriglyceridemia (odds ratio 2.24), hypo-HDL-cholesterolemia (odds ratio 4.56), and hyperglycemia (odds ratio 4.09) in AI patients was significantly higher than in controls. Furthermore, the metabolic syndrome, previously defined as the presence of at least three of the five alterations listed above, was more common in those patients compared to controls (40.0% versus 13.0%; odds ratio 4.46, 95% confidence interval 2.02 to 9.96; P<0.001). AI patients with metabolic syndrome also had more pronounced metabolic alterations than controls with metabolic syndrome. Interestingly, there was no correlation between the severity or duration of the disease and the levels of respective parameters or the number of criteria defining the metabolic syndrome. Rather, the metabolic syndrome was observed in a disproportionately high percentage of young AI patients.

Conclusions

This study shows for the first time that AI patients have a high prevalence of the metabolic syndrome and all of its criteria. It further suggests that the inflammation present in AI patients does not have a major impact on the development of metabolic alterations. Instead, evidence is given for a role of metabolic alterations in the development of AI. We recommend monitoring of AI patients in order to correct their modifiable cardiovascular risk factors.     

Joint Association of Sitting Time and Physical Activity with Metabolic Risk Factors among Middle-Aged Malays in a Developing Country: A Cross-Sectional Study

Background

Prolonged sitting is associated with increased weight and higher risks for abdominal obesity, dyslipidaemia, hyperglycaemia and hypertension among the adult population. This has been well documented in the West, but studies on these associations are lacking in developing countries, including Malaysia.

Objective

This cross-sectional study aimed to examine the joint association of sitting time and physical activity with metabolic risk factors among middle-aged working adults.

Methodology

A total of 686 Malay men and women participated (mean age 45.9±6.5 years). Metabolic syndrome was diagnosed from the modified NCEP ATP III criteria. Self-reported sitting time was obtained with the validated Malay version of the International Physical Activity Questionnaire. Participants were asked about their time spent sitting during travel in a motor vehicle, e.g., car, motorcycle or bus, over the preceding 7 days. Logistic regression was used to estimate the odds ratio with the confidence interval for the combined effects of sitting quartiles and physical activity categories with metabolic risk factors.

Results/Significance

The prevalence of metabolic syndrome among our participants was 31.9%. Their average total sitting time (including transportation) was 7.6±2.4 h/day. After we adjusted for gender and educational level, higher sitting quartiles and physically inactive groups were associated with higher odds for metabolic syndrome compared with the referent group (sitting <6 h/day and physically active). In the physically active stratum, the odds for metabolic syndrome in participants who sat ≥9.3 h/day was 3.8 times that of participants who sat <6 h/day. Both higher sitting quartiles and insufficient physical activity were associated with adverse effects on abdominal obesity, hypertriglyceridemia and hyperglycaemia.

Conclusion

In joint analyses of sitting time and physical activity, higher sitting time and insufficient physical activity were deleteriously associated with odds for metabolic risk factors in middle-aged Malay men and women.     

Angiotensin-converting enzyme inhibition and food restriction in diabetic mice do not correct the increased sensitivity for ischemia-reperfusion injury

Background

Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model.

Methods

Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-?? and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age.

Results

MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p?=?0.001, 9-mo: p?=?0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-?? were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32?±?2, H: 42?±?2, C: 45?±?2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%).

Conclusions

MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.     

Hyperferritinemia is associated with insulin resistance and fatty liver in patients without iron overload

Objective

During the last 10 years we have experienced an increasing number of referrals due to hyperferritinemia. This is probably due to increased awareness of hereditary hemochromatosis, and the availability of a genetic test for this condition. Most of these referred patients were over-weight middle-aged men with elevated ferritin levels, but without the hemochromatosis-predisposing gene mutations. We evaluated the relationship between hyperferritinemia and the metabolic syndrome in 40 patients.

Methods

Forty consecutive patients referred for hyperferritinemia were investigated. The examination programme included medical history, clinical investigation and venous blood samples drawn after an overnight fast. This resulted in 34 patients with unexplained hyperferritinemia, which were further examined. Liver biopsy was successfully performed in 29 subjects. Liver iron stores were assessed morphologically, and by quantitative phlebotomy in 16 patients.

Results

The majority of the patients had markers of the metabolic syndrome, and 18 patients (52%) fulfilled the IDF-criteria for the metabolic syndrome. Mean body mass index was elevated (28,8±4,2), mean diastolic blood pressure was 88,5±10,5 mmHg, and mean fasting insulin C-peptide 1498±539 pmol/l. Liver histology showed steatosis and nuclear glycogen inclusions in most patients (19 out of 29). Only four patients had increased iron stores by histology, of which two could be explained by alcohol consumption. Fourteen of 16 patients normalized ferritin levels after phlebotomy of a cumulative blood amount corresponding to normal iron stores. Ferritin levels were significantly related to insulin C-peptide level (p<0.002) and age (p<0.002).

Conclusion

The present results suggest that liver steatosis and insulin resistance but not increased iron load is frequently seen in patients referred for suspected hemochromatosis on the basis of hyperferritinemia. The ferritin level seems to be positively associated to insulin resistance.     

Insulin resistance syndrome,body mass index and the risk of ischemic heart disease

Background

Many people who are not obese according to standard height and weight criteria may still display features of insulin resistance syndrome and thus be at high risk of ischemic heart disease. We sought to investigate the effect of cumulative features of insulin resistance syndrome on the risk of ischemic heart disease associated with variations in body mass index (BMI) among men who participated in the Québec Cardiovascular Study.

Methods

A cohort of 1824 nondiabetic men free of ischemic heart disease was evaluated at the 1985 baseline evaluation and followed for a period of 13 years, during which 284 first ischemic heart disease events were recorded. Relative hazards (RHs) of ischemic heart disease in 3 BMI groups (normal weight, overweight and obese) were estimated using Cox proportional hazards regression.

Results

Although obese men (BMI ≥ 30 kg/m²) were the most likely to accumulate features of insulin resistance syndrome, the univariate risk of ischemic heart disease in this group was not significantly increased compared with normal-weight men (BMI < 25 kg/m²) (RH 1.26, 95% confidence interval [CI] 0.88–1.80). However, obese men who accumulated more than 4 features of insulin resistance syndrome were at increased risk of ischemic heart disease (RH 1.81, 95% CI 1.02–3.19) compared with normal-weight men who had fewer than 3 features of the syndrome. Conversely, having more than 4 features of insulin resistance syndrome was associated with a 3-fold increase in the risk of ischemic heart disease among normal-weight men (RH 3.01, 95% CI 1.70–5.32).

Interpretation

Although obesity is an important risk factor for ischemic heart disease, variations in BMI alone poorly reflect the risk of ischemic heart disease associated with features of insulin resistance syndrome.In the late 1980s, Gerald Reaven proposed the concept of insulin resistance as the cornerstone of a plurimetabolic syndrome that included hypertriglyceridemia, low plasma high-density lipoprotein cholesterol concentrations, hypertension and hyperinsulinemia.¹ This syndrome has been referred to as syndrome X, insulin resistance syndrome and the metabolic syndrome.² Several other metabolic disturbances, such as an increase in the number of small, dense low-density lipoprotein particles, impaired fibrinolytic activity, a proinflammatory state, impaired postprandial lipoprotein metabolism and abdominal obesity, have been included as part of this syndrome over the years.^3,4Although obesity is an important component of insulin resistance syndrome, many people who are not obese according to standard height and weight criteria (i.e., body mass index [BMI]) may still display features of the syndrome. Indeed, studies have indicated that normal-weight subjects, whose BMI is less than 25 kg/m², may have as much as 40% fat in the abdominal area, a level that correlates closely with decreased insulin sensitivity⁵ and an atherogenic dyslipidemic state. In that context, the risk of ischemic heart disease among normal-weight people with insulin resistance syndrome and among obese people without insulin resistance syndrome represents a major gap in the existing literature. We therefore sought to investigate how features of insulin resistance syndrome affected the risk of ischemic heart disease associated with variations in BMI in a cohort of 1824 men who participated in the Québec Cardiovascular Study.     

Prevalence of metabolic syndrome in the Canadian adult population

Background:

Metabolic syndrome refers to a constellation of conditions that increases a person’s risk of diabetes and cardiovascular disease. We describe the prevalence of metabolic syndrome and its components in relation to sociodemographic factors in the Canadian adult population.

Methods:

We used data from cycle 1 of the Canadian Health Measures Survey, a cross-sectional survey of a representative sample of the population. We included data for respondents aged 18 years and older for whom fasting blood samples were available; pregnant women were excluded. We calculated weighted estimates of the prevalence of metabolic syndrome and its components in relation to age, sex, education level and income.

Results:

The estimated prevalence of metabolic syndrome was 19.1%. Age was the strongest predictor of the syndrome: 17.0% of participants 18–39 years old had metabolic syndrome, as compared with 39.0% of those 70–79 years. Abdominal obesity was the most common component of the syndrome (35.0%) and was more prevalent among women than among men (40.0% v. 29.1%; p = 0.013). Men were more likely than women to have an elevated fasting glucose level (18.9% v. 13.6%; p = 0.025) and hypertriglyceridemia (29.0% v. 20.0%; p = 0.012). The prevalence of metabolic syndrome was higher among people in households with lower education and income levels.

Interpretation:

About one in five Canadian adults had metabolic syndrome. People at increased risk were those in households with lower education and income levels. The burden of abdominal obesity, low HDL (high-density lipoprotein) cholesterol and hypertriglyceridemia among young people was especially of concern, because the risk of cardiovascular disease increases with age.Chronic disease contributes significantly to morbidity and mortality in the Canadian population.¹ As such, the economic costs are substantial. Metabolic syndrome refers to a constellation of conditions that approximately doubles a person’s risk of cardiovascular disease, independently of other risk factors.^2–5 The cause of metabolic syndrome has not been fully elucidated; a summary of the current proposed mechanisms is discussed elsewhere.⁶Several sets of criteria have been established for the detection of metabolic syndrome, many of which have been continually updated.^6–8 The set of criteria most commonly used in the past was published in the third report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III criteria).⁹ Recently, the International Diabetes Federation, the American Heart Association, the National Heart, Lung, and Blood Institute, and other organizations collaborated to release a unified set of criteria.¹⁰The Canadian Health Measures Survey, conducted in 2007–2009, was the first cross-sectional survey of a representative sample of Canadians that collected biological samples since the Canadian Heart Health Surveys about 20 years ago.¹¹ We used data from the Canadian Health Measures Survey to describe the prevalence of metabolic syndrome and its components by age, sex, education level and income adequacy in a sample of the Canadian adult population. Because different studies have used various criteria in the past to define metabolic syndrome, and because there is continuing controversy as to the appropriate criteria, we calculated the prevalence according to several types of criteria to better facilitate comparison to findings from past and future studies.     

Effects of PPARγ and RBP4 Gene Variants on Metabolic Syndrome in HIV-Infected Patients with Anti-Retroviral Therapy

Background

PPARγ and RBP4 are known to regulate lipid and glucose metabolism and insulin resistance. The influences of PPARγ (C1431T and Pro12Ala) and RBP4 (−803GA) polymorphisms on metabolic syndrome in HIV-infected patients receiving anti-retroviral therapy were examined in this study.

Materials and Methods

A cross-sectional study of HIV-1 infected adults with antiretroviral therapy for more than one year in the National Cheng Kung University Hospital was conducted. The gene polymorphisms were determined by quantitative PCR.

Results

Ninety-one patients were included in the study. Eighty-two (90.1%) patients were males with a mean age of 44.4 years. For the C1431T polymorphism in PPARγ, while patients with the T allele (48.4%) had trends toward lower rate of hypertriglyceridemia, the borderline significance together with insignificant power did not support the protective effect of the T allele against development of hypertriglyceridemia. For the Pro12Ala polymorphism in PPARγ, although patients with the Pro/Ala genotype (8.8%) had a higher level of serum LDL (138.0 vs. 111.5 mg/dl, P = 0.04) and trends toward higher rates of hypercholesterolemia and serum LDL>110 mg/dl, these variables were found to be independent of the Pro/Ala genotype in the multivariate analysis. For the −803GA polymorphism in RBP4, patients with the A allele (23.1%) more often had insulin resistance (HOMA>3.8; 33.3 vs. 8.7%, P = 0.01) and more often received anti-hypoglycemic drugs (14.3 vs. 1.4%, P = 0.04). The detrimental effect of the A allele in RBP4 −803GA polymorphism on development of insulin resistance was supported by the multivariate analysis adjusting for covariates.

Conclusion

The impacts of PPARγ C1431T and Pro12Ala polymorphisms on metabolism in HIV-infected patients are not significant. RBP4 −803GA polymorphism has increased risk of insulin resistance in HIV-infected patients with anti-retroviral therapy.     

Components of Metabolic Syndrome as Risk Factors for Hearing Threshold Shifts

Background

Hearing loss was a common, chronically disabling condition in the general population and had been associated with several inflammatory diseases. Metabolic syndrome, which was associated with insulin resistance and visceral obesity, was considered a chronic inflammatory disease. To date, few attempts had been made to establish a direct relationship between hearing loss and metabolic syndrome. The aim of the present study was to investigate the relationship between metabolic syndrome and hearing loss by analyzing the data in the reports of the National Health and Nutrition Examination Survey 1999–2004.

Methods

This study included 2100 participants aged ≤ 65 years who enrolled in the National Health and Nutrition Examination Survey (1999–2004). We examined the relationship between the presence of different features of metabolic syndrome in the participants and their pure-tone air-conduction hearing thresholds, including low-frequency and high-frequency thresholds.

Results

After adjusting for potential confounders, such as age, medical conditions, and smoking status, the participants with more components of metabolic syndrome were found to have higher hearing thresholds than those with fewer components of metabolic syndrome (p < 0.05 for a trend). The low-frequency hearing threshold was associated with individual components of metabolic syndrome, such as abdominal obesity, high blood pressure, elevated triglycerides, and a low level of high-density lipoprotein cholesterol (HDL-C) (p < 0.05 for all parameters).

Conclusions

The results indicated that the presence of a greater number of components of metabolic syndrome was significantly associated with the hearing threshold in the US adult population. Among the components of metabolic syndrome, the most apparent association was observed between low HDL and hearing loss.     

Disruption of insulin signalling preserves bioenergetic competence of mitochondria in ageing <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis>

Background  

The gene daf-2 encodes the single insulin/insulin growth factor-1-like receptor of Caenorhabditis elegans. The reduction-of-function allele e1370 induces several metabolic alterations and doubles lifespan.