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We describe the association between high density lipoprotein cholesterol (HDL-C) concentration and computed tomography (CT)-measured fat depots.
We examined the cross-sectional associations between HDL-C concentration and intra-abdominal (IAF), abdominal subcutaneous (SCF), and thigh fat (TF) areas in 641 Japanese-American men and women. IAF, SCF, and TF were measured by CT at the level of the umbilicus and mid-thigh. The associations between fat area measurements and HDL-C were examined using multivariate linear regression analysis adjusting for age, sex, diabetes family history, homeostasis model assessment of insulin resistance (HOMA-IR), and body mass index (BMI). Non-linearity was assessed using fractional polynomials.
Mean±standard deviation of HDL-C concentration and IAF in men and women were 1.30±0.34 mg/dL, 105±55.3 cm2, and 1.67±0.43 mg/dL, 74.4±46.6 cm2 and differed significantly by gender for both comparisons (
HDL-C does not linearly decline with increasing IAF in Japanese-Americans. A more complex pattern better fits this association.
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Few studies have examined the association between mercury exposure and obesity. The aim of this study is to investigate the association between blood mercury concentrations and indices of obesity in adults.
A total of 200 healthy subjects, aged 30 to 64 years, who had no history of cardiovascular or malignant disease, were examined. Anthropometric and various biochemical profiles were measured. Visceral adipose tissue (VAT) was measured using dual-energy X-ray absorptiometry (DXA).
All subjects were divided into three groups according to blood mercury concentrations. Compared with the subjects in the lowest tertile of mercury, those in the highest tertile were more likely to be male; were current alcohol drinkers and smokers; had a higher body mass index (BMI), waist circumference (WC), and VAT; had higher levels of blood pressure, fasting glucose, and insulin resistance; and consumed more fish. The blood mercury concentration was significantly associated with anthropometric parameters, showing relationships with BMI, WC, and VAT. After adjusting for multiple risk factors, the odds ratios (ORs) for high mercury concentration was significantly higher in the highest VAT tertile than in the lowest VAT tertile (OR, 2.66; 95% confidence interval, 1.05 to 6.62;
The blood mercury concentration was significantly associated with VAT in healthy adults. Further studies are warranted to confirm our findings.
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Nonalcoholic fatty liver disease (NAFLD) is closely correlated with abnormal accumulation of visceral fat, but the role of skeletal muscle remains unclear. The aim of this study was to elucidate the role of skeletal muscle in development of NAFLD.
Among 11,116 subjects (6,242 males), we examined the effects of skeletal muscle mass and visceral fat area (VFA, by bioelectric impedance analysis) on NAFLD using by the fatty liver index (FLI).
Of the total subjects (9,565 total, 5,293 males) included, 1,848 were classified as having NALFD (FLI ≥60). Body mass index, lipid profile, fasting plasma glucose, hemoglobin A1c, prevalence of type 2 diabetes (DM), hypertension (HTN), and metabolic syndrome were higher in males than females, but FLI showed no significant difference. The low FLI group showed the lowest VFA and highest skeletal muscle mass of all the groups. Skeletal muscle to visceral fat ratio (SVR) and skeletal muscle index had inverse correlations with FLI, when adjusted for age and gender. In multivariate regression analysis, SVR was negatively associated with FLI. Among SVR quartiles, the highest quartile showed very low risk of NAFLD when adjusted for age, gender, lipid profile, DM, HTN, and high sensitivity C-reactive protein from the lowest quartiles (odds ratio, 0.037; 95% confidence interval, 0.029 to 0.049).
Skeletal muscle mass was inversely associated with visceral fat area, and higher skeletal muscle mass may have a beneficial effect in preventing NAFLD. These results suggest that further studies are needed to ameliorate or slow the progression of sarcopenia.
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The aim of this study was to investigate the influences of visceral adiposity on cardiovascular autonomic neuropathy (CAN) in patients with type 2 diabetes mellitus.
Two hundred eleven patients with type 2 diabetes participated in this study. Anthropometric and metabolic parameters were measured, and the visceral fat area was assessed using computed tomography. CAN was diagnosed using a cardiovascular reflex test. We analyzed the correlation between the visceral fat area and each parameter in this test.
The mean age, body mass index (BMI), and duration of diabetes of the study population were 60±14 years (mean±standard deviation), 25.1±4.2 kg/m2, and 12.3±8.9 years, respectively. The visceral fat area showed positive correlations with age, BMI, waist circumference, and subcutaneous fat area. There was no statistically significant difference in the cardiovascular reflex test outcome between genders. Univariate linear regression analysis showed that an increased visceral fat area diminished good heart rate response to a Valsalva maneuver (
The results of this study suggest that visceral adiposity contributes to an autonomic imbalance to some degree, as demonstrated by the impaired cardiovascular reflex test among women with type 2 diabetes.
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The hypothalamus, the center for body weight regulation, can sense changes in blood glucose level based on ATP-sensitive potassium (KATP) channels in the hypothalamic neurons. We hypothesized that a lack of glucose sensing in the hypothalamus affects the regulations of appetite and body weight.
To evaluate this hypothesis, the responses to glucose loading and high fat feeding for eight weeks were compared in Kir6.2 knock-out (KO) mice and control C57BL/6 mice, because Kir6.2 is a key component of the KATP channel.
The hypothalamic neuropeptide Y (NPY) analyzed one hour after glucose injection was suppressed in C57BL/6 mice, but not in Kir6.2 KO mice, suggesting a blunted hypothalamic response to glucose in Kir6.2 KO mice. The hypothalamic NPY expression at a fed state was elevated in Kir6.2 KO mice and was accompanied with hyperphagia. However, the retroperitoneal fat mass was markedly decreased in Kir6.2 KO mice compared to that in C57BL/6 mice. Moreover, the body weight and visceral fat following eight weeks of high fat feeding in Kir6.2 KO mice were not significantly different from those in control diet-fed Kir6.2 KO mice, while body weight and visceral fat mass were elevated due to high fat feeding in C57BL/6 mice.
These results suggested that Kir6.2 KO mice showed a blunted hypothalamic response to glucose loading and elevated hypothalamic NPY expression accompanied with hyperphagia, while visceral fat mass was decreased, suggesting resistance to diet-induced obesity. Further study is needed to explain this phenomenon.
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