This cross sectional study aims to investigate the associations between ectopic lipid accumulation in liver and skeletal muscle and biochemical measures, estimates of insulin resistance, anthropometry, and blood pressure in lean and overweight/obese children.
Fasting plasma glucose, serum lipids, serum insulin, and expressions of insulin resistance, anthropometry, blood pressure, and magnetic resonance spectroscopy of liver and muscle fat were obtained in 327 Danish children and adolescents aged 8-18 years.
In 287 overweight/obese children, the prevalences of hepatic and muscular steatosis were 31% and 68%, respectively, whereas the prevalences in 40 lean children were 3% and 10%, respectively. A multiple regression analysis adjusted for age, sex, body mass index z-score (BMI SDS), and pubertal development showed that the OR of exhibiting dyslipidemia was 4.2 (95%CI: [1.8; 10.2], p = 0.0009) when hepatic steatosis was present. Comparing the simultaneous presence of hepatic and muscular steatosis with no presence of steatosis, the OR of exhibiting dyslipidemia was 5.8 (95%CI: [2.0; 18.6], p = 0.002). No significant associations between muscle fat and dyslipidemia, impaired fasting glucose, or blood pressure were observed. Liver and muscle fat, adjusted for age, sex, BMI SDS, and pubertal development, associated to BMI SDS and glycosylated hemoglobin, while only liver fat associated to visceral and subcutaneous adipose tissue and intramyocellular lipid associated inversely to high density lipoprotein cholesterol.
Hepatic steatosis is associated with dyslipidemia and liver and muscle fat depositions are linked to obesity-related metabolic dysfunctions, especially glycosylated hemoglobin, in children and adolescents, which suggest an increased cardiovascular disease risk.
Cites: Child Obes. 2012 Dec;8(6):533-4123181919
Cites: Int J Pediatr Obes. 2011 Aug;6(3-4):188-9621529264
Cites: Int J Obes (Lond). 2014 Jan;38(1):40-523828099
Abdominal obesity is a major risk factor for hypertension. However, different distributions of abdominal adipose tissue may affect hypertension risk differently. The main purpose of this study was to explore the association of subcutaneous abdominal adipose tissue (SAT) and visceral adipose tissue (VAT) with incident hypertension in a population-based setting. We hypothesized that VAT, rather than SAT, would be associated with incident hypertension. VAT and SAT were determined by ultrasound imagining in 3363 randomly selected Danes (mean age 49 years, 56% women, mean body mass index 25.8 kg/m(2)). We constructed multiple logistic regression models to compute standardized odds ratios with 95% confidence intervals per SD increase in SAT and VAT. Of the 2119 normotensive participants at baseline, 1432, with mean SAT of 2.8 cm and mean VAT of 5.7 cm, returned 5 years later for a follow-up examination and among them 203 had developed hypertension. In models including both VAT and SAT, the Framingham Hypertension Risk Score variables (age, sex, smoking status, family history of hypertension, and baseline blood pressure) and glycated hemoglobin, odds ratio (95% confidence interval) for incident hypertension for 1 SD increase in VAT and SAT was 1.27 (1.08-1.50, P=0.004) and 0.97 (0.81-1.15, P=0.70), respectively. Adjusting for body mass index instead of SAT attenuated the association between VAT and incident hypertension, but it was still significant (odds ratio, 1.22 [1.01-1.48, P=0.041] for each SD increase in VAT). In conclusion, ultrasound-determined VAT, but not SAT, was associated with incident hypertension in a random sample of Danish adults.
Previous studies have indicated that fat distribution is important in the development of cardiovascular disease (CVD). We investigated the association between fat distribution, as measured by dual energy X-ray absorptiometry (DXA), and the incidence of stroke.
A cohort of 2751 men and women aged =40 years was recruited. Baseline levels of abdominal, gynoid and total body fat were measured by DXA. Body mass index (BMI, kg?m(-2)) was calculated. Stroke incidence was recorded using the regional stroke registry until subjects reached 75 years of age.
During a mean follow-up time of 8 years and 9 months, 91 strokes occurred. Of the adiposity indices accessed abdominal fat mass was the best predictor of stroke in women (hazard ratio (HR)=1.66, 95% confidence interval (CI)=1.23-2.24 per standard deviation increase), whereas the ratio of gynoid fat to total fat mass was associated with a decreased risk of stroke (HR=0.72, 95% CI=0.54-0.96). Abdominal fat mass was the only of the adiposity indices assessed that was found to be a significant predictor of stroke in men (HR=1.49, 95% CI=1.06-2.09). The associations between abdominal fat mass and stroke remained significant in both women and men after adjustment for BMI (HR=1.80, 95% CI=1.06-3.07; HR=1.71, 95% CI=1.13-2.59, respectively). However, in a subgroup analyses abdominal fat was not a significant predictor after further adjustment for diabetes, smoking and hypertension.
Abdominal fat mass is a risk factor for stroke independent of BMI, but not independent of diabetes, smoking and hypertension. This indicates that the excess in stroke risk associated with abdominal fat mass is at least partially mediated through traditional stroke risk factors.
Several organizations recommend the use of measures of abdominal obesity in conjunction with body mass index (BMI) to assess obesity-related health risk. Recent evidence suggests that waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) are increasing within BMI categories. This shift may have affected the usefulness of abdominal obesity measures.
Data are from respondents aged 18 to 79 to the 2007 to 2009 Canadian Health Measures Survey. Using logistic regression, this paper examines cardiovascular disease (CVD) risk factors in relation to WC, WHR and WHtR within BMI health-risk categories. CVD risk factors considered include components of the metabolic syndrome.
Among men in the normal and overweight BMI categories, WHR and WHtR were positively associated with having at least two CVD risk factors. All three abdominal obesity measures were associated with increased odds of having at least two CVD risk factors among normal-weight women. Abdominal obesity was not associated with CVD risk factors for people in obese class I.
Among men and women in the normal BMI category, measures of abdominal obesity are associated with increased odds of CVD risk factors. This underscores the importance of measuring and monitoring abdominal obesity in normal-weight men and women.
It has been hypothesized that visceral fat releases free fatty acids and adipokines and thereby exposes the liver to fat accumulation. The authors aimed to evaluate current epidemiologic evidence for an association between abdominal fat and liver fat content. Clinical and epidemiologic studies with data on abdominal fat and liver fat content were reviewed. Studies using waist circumference to estimate abdominal fat mass suggested a direct association between abdominal fat and liver fat content. Studies using imaging methods suggested a direct association between intraabdominal fat and liver fat content, but not between subcutaneous abdominal fat and liver fat content. In conclusion, clinical and epidemiologic studies of abdominal fat and liver fat content suggest a direct association between abdominal fat and liver fat content which is probably accounted for by visceral fat. However, results from the included studies do not allow strong conclusions regarding the temporal sequence of events. Future longitudinal studies are recommended to obtain additional information on associations and mechanisms. Both abdominal fat depots and other body compartments of interest should be included to further investigate the association between specific fat depots and liver fat content. Biomarkers may provide insight into underlying mechanisms.
OBJECTIVE: To explore the association between abdominal obesity and insulin resistance in patients with type 2 diabetes. DESIGN: A cross-sectional observational study. SETTING: Primary care in Skara, Sweden. SUBJECTS: A total of 198 men and 186 women with type 2 diabetes who consecutively completed an annual check-up in 1992-1993. MAIN OUTCOME MEASURES: Abdominal obesity was defined according to criteria for the metabolic syndrome using the waist circumference (WC): > 102 cm for men and > 88 cm for women. Insulin resistance was estimated using the Homeostasis Model Assessment (HOMA), and was dichotomized by the 75th percentile (IR). RESULTS: Abdominal obesity was found in 66 men (33%), and in 106 women (57%). Pearson's correlation coefficients between components of the metabolic syndrome and IR were statistically significant for WC, waist-hip ratio, serum triglycerides, and HDL cholesterol, and were higher for WC (0.40) than for waist-hip ratio (0.23) in both genders (p
The metabolic syndrome is a cluster of cardiovascular risk factors, including abdominal obesity, hypertension, dyslipidemia and insulin resistance, associated with increased risk of cardiovascular diseases and all cause mortality.
The purpose of the study was to assess the impact of the metabolic syndrome, and its individual components, on the risk of venous thromboembolism (VTE) in a prospective population-based study.
Individual components of the metabolic syndrome were registered in 6170 subjects aged 25-84 years in the Tromsø Study in 1994-1995, and first ever VTE events were registered until 1 September 2007.
The metabolic syndrome was present in 21.9% (1350 subjects) of the population. There were 194 validated first VTE events (2.92 per 1000 person-years) during a mean of 10.8 years of follow-up. Presence of metabolic syndrome was associated with increased risk of VTE (HR, 1.65; 95% CI, 1.22-2.23) in age- and gender-adjusted analysis. The risk of VTE increased with the number of components in the metabolic syndrome (P
Differences in subcutaneous abdominal adipose tissue (SAT) fat cell size and number (cellularity) are linked to insulin resistance. Men are generally more insulin resistant than women but it is unknown whether there is a gender dimorphism in SAT cellularity. The objective was to determine SAT cellularity and its relationship to insulin sensitivity in men and women.
In a cohort study performed at an outpatient academic clinic in Sweden, 798 women and 306 men were included. Estimated SAT mass (ESAT) was derived from measures of dual-energy X-ray absorptiometry and a formula. SAT biopsies were obtained to measure mean fat cell size; SAT adipocyte number was obtained by dividing ESAT with mean fat cell weight. Fat cell size was also compared with level of insulin sensitivity in vivo.
Over the entire range of body mass index (BMI) both fat cell size and number correlated positively with ESAT in either sex. On average, fat cell size was larger in men than in women, which was driven by significantly larger fat cells in non-obese men compared with non-obese women; no gender effect on fat cell size was seen in obese subjects. For all subjects fat cell number was larger in women than men, which was driven by a gender effect among non-obese individuals (P
The benefits of sportfish consumption and omega-3 fatty acid (omega3-FA) intake for cardiovascular risk factors were evaluated in a sample of 112 male fishers from the St. Lawrence River in the Montreal area during the 1996 winter and fall fishing seasons. A questionnaire on fishing practices and fish consumption was administered, and fasting blood samples were collected for lipid and phospholipid determination. Linear regression analyses, which considered the confounding effect of major risk factors, did not show any significant association between measured omega3-FAs or reported fish intake and blood lipids or blood pressure. This study is limited by its low statistical power due to the small sample size and the possibility that the fish eaten by the participants were low in omega3-FAs or that the participants diets contained foods high in cholesterol-raising fat.
Insulin resistance is associated with hypertension by mechanisms likely involving the kidney. To determine how the major apical sodium transporter of the thick ascending limb, the bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) is regulated by high-fat feeding, we treated young male, Fischer 344 X Brown Norway (F344BN) rats for 8 wk with diets containing either normal (NF, 4%) or high (HF, 36%) fat, by weight, primarily as lard. HF-fed rats had impaired glucose tolerance, increased urine excretion of 8-isoprostane (a marker of oxidative stress), increased protein levels for NKCC2 (50-125%) and the renal outer medullary potassium channel (106%), as well as increased natriuretic response to furosemide (20-40%). To test the role of oxidative stress in this response, in study 2, rats were fed the NF or HF diet plus plain drinking water, or water containing N(G)-nitro-l-arginine methyl ester (l-NAME), a nitric oxide synthase inhibitor (100 mg/l), or tempol, a superoxide dismutase mimetic (1 mmol/l). The combination of tempol with HF nullified the increase in medullary NKCC2, while l-NAME with HF led to the highest expression of medullary NKCC2 (to 498% of NF mean). However, neither of these drugs dramatically affected the elevated natriuretic response to furosemide with HF. Finally, l-NAME led to a marked increase in blood pressure (measured by radiotelemetry), which was significantly enhanced with HF. Mean arterial blood pressure at 7 wk was as follows (mmHg): NF, 100 +/- 2; NF plus l-NAME, 122 +/- 3; and HF plus l-NAME, 131 +/- 2. Overall, HF feeding increased the abundance of NKCC2. Inappropriately high sodium reabsorption in the thick ascending limb via NKCC2 may contribute to hypertension with insulin resistance.