Wing-Bun Chan

Sonographic measurement of mesenteric fat thickness is a good correlate with cardiovascular risk factors: comparison with subcutaneous and preperitoneal fat thickness, magnetic resonance imaging and anthropometric indexes

OBJECTIVE: Visceral fat, notably mesenteric fat, which is drained by the portal circulation, plays a critical role in the pathogenesis of metabolic syndrome through increased production of free fatty acids, cytokines and vasoactive peptides. We hypothesize that mesenteric fat thickness as measured by ultrasound scan could explain most of the obesity-related health risk. We explored the relationships between cardiovascular risk factors and abdominal fat as determined by sonographic measurements of thickness of mesenteric, preperitoneal and subcutaneous fat deposits, total abdominal and visceral fat measurement by magnetic resonance imaging (MRI) and anthropometric indexes.DESIGN: A cross-sectional study.SUBJECTS: Subjects included 18 healthy men and 19 women (age: 27–61 y, BMI: 19–33.4 kg/m2).MEASUREMENTS: The maximum thickness of mesenteric, preperitoneal and subcutaneous fat was measured by abdominal ultrasound examination. MRI examinations of whole abdomen and pelvis were performed and the amount of total abdominal and visceral fat was quantified. The body mass index, waist circumference and waist–hip ratio were recorded. Cardiovascular risk factors were assessed by physical examination and blood taking.RESULTS: Men had more adverse cardiovascular risk profile, higher visceral fat volume and thicker mesenteric fat deposits than women. Among all the investigated obesity indexes, the mesenteric fat thickness showed the highest correlations with total cholesterol, LDL-C, triglycerides, fasting plasma glucose, HbA1c and systolic blood pressure in men, and with triglycerides and HbA1c in women. On stepwise multiple regression analysis with different obesity indexes as independent variables, 30–65% of the variances of triglycerides, total cholesterol, LDL-C and HbA1c in men, and triglycerides in women were explained by the mesenteric fat thickness.CONCLUSION: Compared with sonographic measurement of subcutaneous and preperitoneal fat thickness, MRI measurement of total abdominal and visceral fat and anthropometric indexes, sonographic measurement of mesenteric fat thickness showed better associations with some of the cardiovascular risk factors. It may potentially be a useful tool to evaluate regional distribution of obesity in the assessment of cardiovascular risk.

Prevalence and distribution of Helicobacter pylori in gastroesophageal reflux disease: a study from the East

OBJECTIVES:The relationship between Helicobacter pylori infection and gastroesophageal reflux (H. pylori) disease (GERD) is controversial. In Asian populations, the prevalence of H. pylori infection is high and GERD is relatively uncommon. The aim of this study was 1) to test the hypothesis that H. pylori protects the esophagus against GERD, and 2) to study the pattern of H. pylori colonization and gastritis in GERD.METHODS:We conducted a prospective case-control study in which patients with GERD and asymptomatic controls were compared for the prevalence of H. pylori infection. Diagnosis of GERD was based on symptoms of heartburn that improved with acid-suppressive therapy and/or endoscopic evidence of erosive esophagitis. H. pylori status was determined by serology and, when endoscopy was indicated, was confirmed by rapid urease test and histology. Gastric biopsies were examined under hematoxylin and eosin and Giemsa stains. Density of H. pylori colonization and activity of gastritis at different parts of stomach were graded and compared according to Updated Sydney system.RESULTS:A total of 106 patients with GERD and 120 age- and sex-matched, asymptomatic controls were enrolled. The prevalence of H. pylori infection was significantly lower in GERD patients (31%) compared with controls (61%, p < 0.001, odds ratio 0.229, 95% confidence interval 0.13–0.41). H. pylori-infected GERD patients showed significantly more severe gastritis in the antrum than in other parts of stomach (mean inflammatory scores: antrum; 3.3 ± 1.63*, body; 1.85 ± 1.31; fundus; 1.65 ± 0.58; cardia, 1.65 ± 1.39; *p < 0.005). H. pylori colonization was found less commonly and at lower density at the cardia compared with other parts of the stomach.CONCLUSIONS:H. pylori infection protects against the development of GERD, and carditis is unlikely to play an important role.

Gastrointestinal symptoms in Chinese patients with Type 2 diabetes mellitus.

Aims To examine and compare gastrointestinal (GI) symptoms in Hong Kong Chinese Type 2 diabetic outpatients and non‐diabetic control subjects.

The associations of body mass index, C-peptide and metabolic status in Chinese Type 2 diabetic patients.

Background  Chinese Type 2 diabetic subjects are generally less obese than their Caucasian counterparts. We hypothesized that lean and obese Chinese Type 2 diabetic subjects have different metabolic and insulin secretory profiles. We compared the clinical features, C peptide and metabolic status between lean/normal weight and obese diabetic subjects.

HELICOBACTER PYLORI INFECTION IN CHINESE SUBJECTS WITH TYPE 2 DIABETES

The relationship between diabetes and Helicobacter pylori (HP) infection is controversial. In this study, we examined the possible relationship between HP infection and type 2 diabetes in Chinese subjects. Sixty-three Chinese type 2 diabetic patients (mean age ± SD: 49.9 ± 12.0 years; range: 17–76 years) were recruited irrespective of the duration of diabetes or type of therapy. Twenty-nine (46%) of them had upper gastrointestinal symptoms and the other 34 (54%) did not. Another 55 age- and sex-matched non-diabetic subjects (mean age ± SD: 45.6 ± 15.6 years, p = 0.098; range 18–79 years) with dyspepsia indicated for upper endoscopy were recruited as a comparison group. Upper endoscopy was performed with antral mucosal biopsy specimens taken for rapid urease test (CLO test). HP infection was considered to be present if the rapid urease test was positive. The rates of HP infection of the diabetic and non-diabetic individuals were 50.8% and 56.4% respectively (p: NS). The rate of HP infection was similar between the 2 groups of diabetic patients with or without gastrointestinal symptoms (42.9% vs. 56.3%, p: NS). Using logistic regression analysis (forward stepwise) with age, sex, glycaemic control, duration of diabetes and upper gastrointestinal symptoms as independent variables to predict the risk of HP infection in diabetic patients, none of the parameters enter into the model. In conclusion, the rate of HP infection in Hong Kong Chinese subjects with type 2 diabetes is around 50%, which is similar to control subjects. No association was found between HP infection, glycaemic status, and duration of diabetes and upper gastrointestinal symptoms in these diabetic subjects.

Mesenteric fat thickness as an independent determinant of fatty liver

Objective:Mesenteric fat is drained by the portal circulation and has been suggested to be a key component in obesity-related health risk, notably the metabolic syndrome. There are increasing epidemiological and experimental data showing that fatty liver is another component of this multifaceted syndrome. Given their intimate anatomical and physiological relationships, we hypothesized that mesenteric fat thickness may be independently associated with the risk of fatty liver. To test this hypothesis, we examined the predictive role of various fat deposits including mesenteric fat thickness, and various metabolic variables on the risk of fatty liver.Subjects and methods:A total of 291 Chinese subjects (134 men and 157 women with a mean BMI of 23.7 kg/m2, range: 16.5–33.4 kg/m2) underwent ultrasound examination for measurement of mesenteric, subcutaneous and preperitoneal fat thickness, and for diagnosis of fatty liver. Body mass index, waist circumference, and waist–hip ratio were recorded. Blood pressure was measured. Fasting plasma glucose, insulin resistance, high-density lipoprotein cholesterol (HDL-C), triglycerides, low-density lipoprotein cholesterol (LDL-C), liver enzymes were determined by common methods.Results:The subjects with fatty liver had greater abdominal fat thickness and higher anthropometric indexes than those without fatty liver. The subjects with fatty liver also showed higher blood pressure, worse lipid and glycaemic profile compared with those without fatty liver. Using multiple logistic regression analysis, mesenteric fat thickness was a risk factor of fatty liver, independent of body mass index, age, sex, insulin resistance, fasting plasma glucose, lipid and blood pressure. The odds ratio was 1.5 (95% confidence interval: 1.27–1.77) for every 1 mm increase in the mesenteric fat thickness. Measurement of preperitoneal and subcutaneous fat deposits did not show significant associations with fatty liver.Conclusion:Mesenteric fat thickness measured on ultrasound is an independent determinant of fatty liver.

Triglyceride predicts cardiovascular mortality and its relationship with glycaemia and obesity in Chinese type 2 diabetic patients.

To examine the lipid profile in Chinese type 2 diabetic patients and their relationship with anthropometric parameters, glycaemic control and cardiovascular mortality.

Glycated haemoglobin and cardiovascular risk factors in Chinese subjects with normal glucose tolerance.

Increased plasma glucose concentration is a predictive factor for mortality in both diabetic and non‐diabetic subjects. Although glycated haemoglobin (HbA1c) is a useful index of mean blood glucose concentrations over the preceding 1 to 3 months, there are few data regarding its relationship to cardiovascular risk. We have examined the relationship between HbA1c and cardiovascular risk factors in 1280 subjects with normal glucose tolerance. Based on HbA1c tertiles (tertile 1: n = 427, 262 men and 165 women, HbA1c level: 2.9–4.7 % in men and 3.2–4.2 % in women; tertile 2: n = 426, 261 men and 165 women, HbA1c level: 4.7–5.1 % in men and 4.2–4.6 % in women; tertile 3: n = 427, 262 men and 165 women, HbA1c level: 5.1–6.7 % in men and 4.6–6.9 % in women), increasing HbA1c was associated with increasing age, blood pressure, waist–hip ratio, fasting and 2‐h plasma glucose, 2‐h insulin, cholesterol, low‐density lipoprotein cholesterol, apolipo‐ protein B and urate concentrations. When age and sex were included as covariates, increasing HbA1c remained associated with increasing fasting and 2‐h plasma glucose, 2‐h insulin, total cholesterol, and low‐density lipoprotein cholesterol concentrations. These findings emphasize the importance of hyperglycaemia, as reflected by HbA1c, as a continuum in the evaluation of cardiovascular risk. Furthermore, these findings support the hypothesis that cardiovascular disease risk commences with rising glucose concentrations before ‘conventionally‐defined’ glucose intolerance occurs.

Prediction of cardiovascular and total mortality in Chinese type 2 diabetic patients by the WHO definition for the metabolic syndrome

Aim:  The aim of this study is to investigate the prevalence of metabolic syndrome (MES) in type 2 diabetic patients and the predictive values of the World Health Organization (WHO) and National Cholesterol Education Programme (NCEP) definitions and the individual components of the MES on total and cardiovascular mortality.

The preferred magnetic resonance imaging planes in quantifying visceral adipose tissue and evaluating cardiovascular risk

Background:  Magnetic Resonance Imaging (MRI) is a well‐accepted non‐invasive method in the quantification of visceral adipose tissue. However, a standard method of measurement has not yet been universally agreed.