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Biomedical subjects

N N Chan

Publications and source records attributed to N N Chan.

At least 19 recordsLinked to original sources
PubMed2006

Metabolic syndrome by the international diabetes federation definition in Hong Kong Chinese.

In this report, we aimed to examine the impact of the new International Diabetes Federation (IDF) definition on the prevalence and clinical characteristics of subjects with metabolic syndrome (MES). Data were obtained from a prevalence survey for cardiovascular risk factors in a Hong Kong Chinese working population. There were 1513 subjects well representing all occupational groups from managers to general laborers [910 (60.1%) men and 603 (39.9%) women (mean age 37.5+/-9.2, median 37.0, range 18-66 years)]. The crude prevalence of MES defined by the IDF criterion was 7.4% (compared to other criteria: NCEP, 9.6%; WHO, 13.4% and EGIR, 8.9%). The age-standardized prevalence of MES by the IDF criterion was 8.8% in women and 7.3% in men. Subjects with MES defined by IDF criterion had higher body mass index and waist compared to those with MES defined by NCEP or WHO criteria, and lower triglyceride compared to those with MES defined by NCEP criterion after adjustment for age, gender and smoking. Non-MES subjects defined by IDF criterion had higher 2h glucose and insulin resistance compared to non-MES subjects defined by WHO. In conclusion, the new IDF criterion for MES is easy to implement in clinical practice. It may be potentially more 'specific' in identifying subjects with MES although compared to the NCEP criterion, it may have missed a proportion of subjects, especially men, who have metabolic derangement. Prospective and interventional studies are needed to validate the prognostic values of this new definition in comparison with other existing definitions.

Adolescent↗
PubMed2006

Assessment of glomerular filtration rate in addition to albuminuria is important in managing type II diabetes.

Although much emphasis has been placed on screening for albuminuria in type II diabetic patients, less attention has been focused on the role of glomerular filtration rate (GFR) in the assessment of risk. Herein, we examined the association between GFR and vascular complications in a consecutive cohort of 5174 type II diabetic patients between 1995 and 2000. Renal function was assessed by GFR (estimated by Modification of Diet in Renal Disease equation). The frequency of chronic kidney disease (CKD) as defined by GFR <60 ml/min/1.73 m(2), micro- and macrovascular complications, and their associations were analyzed. In this study cohort, 6% had serum creatinine > or =150 micromol/l and 15.8% had CKD. After adjustment for potential confounders, including urinary albumin excretion, odds ratios [95% confidence interval (CI)] across different stages of estimated GFR (> or =90, 60-89, 30-59, 15-29, <15 ml/min/1.73 m(2)) for macrovascular disease were 1.00, 1.42 [1.12-1.80], 1.80 [1.32-2.45], 2.74 [1.64-4.56], and 4.05 [1.77-9.26], respectively (P for trend <0.001); for retinopathy were 1.00, 1.23 [1.04-1.46], 1.80 [1.40-2.30], 2.05 [1.25-3.37], and 4.12 [1.56-10.90], respectively (P for trend <0.001); for sensory neuropathy were 1.00, 1.53[1.27-1.85], 2.09 [1.58-2.76], 4.32 [2.41-7.77], and 3.16 [1.25-8.02], respectively (P for trend <0.001); and for microalbumuria (with GFR <15 ml/min/1.73 m(2) excluded from the analysis) were 1.00, 1.51 [1.30-1.75], 5.80 [4.52-7.44], and 52.5 [16.4-168.2] respectively (P for trend <0.001). Measurement of serum creatinine alone without GFR may underestimate renal impairment in type II diabetic patients. Decreasing GFR was significantly associated with increasing frequency of micro- and macrovascular complications.

Adult↗
PubMed2006

Vascular defect beyond the endothelium in type II diabetic patients with overt nephropathy and moderate renal insufficiency.

There is a paucity of data on the effects of overt nephropathy and moderate renal impairment on endothelial function in diabetic patients. A total of 26 type II diabetic (DM) patients with nephropathy (DMN+) (mean +/- s.d. age: 63.7 +/- 6.3 years), 32 diabetic patients without nephropathy (DMN-) (59.4 +/- 10.1 years), and 52 non-diabetic subjects (54.9 +/- 8.2 years) were recruited. High-resolution ultrasound scan was used to measure carotid intima media thickness (IMT) and flow-mediated dilation (FMD) of the brachial artery. Endothelium-independent dilation was determined by maximal vascular dilation after sublingual nitroglycerine (glyceryl trinitrate (GTN)-induced dilation). The mean carotid IMT increased progressively from non-DM to DMN- to DMN+ groups (0.74 +/- 0.23 vs 0.80 +/- 0.25 vs 1.03 +/- 0.38 mm; P=0.001 for trend) whereas FMD- (4.3 +/- 2.5 vs 3.9 +/- 1.7 vs 1.9 +/- 2.0%, P<0.001 for trend) and GTN-induced dilation (14.7 +/- 4.0 vs 14.5 +/- 3.9 vs 10.3 +/- 3.2%; P<0.001 for trend) declined in an opposite manner. On multivariate analysis, age (beta=0.257, P=0.009), glomerular filtration rate (beta=-0.364, P<0.001), and smoking (beta=0.25, P=0.013) were independently associated with carotid IMT (F=15.76, R(2)=0.340, P<0.001). After adjustment for baseline brachial arterial diameter, history of smoking (beta=-0.039, P<0.001), fasting plasma glucose (beta=-0.033, P=0.002), and total cholesterol (beta=-0.023, P=0.024) were independently associated with vessel diameter after FMD (F=2446.5, R(2)=0.992, P<0.001); whereas age (beta=-0.069, P=0.001) and urinary albumin excretion (beta=-0.048, P=0.018) were independently associated with vessel diameter after GTN (F=851.6, R(2)=0.967, P<0.001). Type II diabetic patients with overt nephropathy and moderate renal impairment had both structural and functional vascular abnormalities beyond the endothelium.

Aged↗
PubMed2006

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. METHODS: A prospective analysis of a consecutive cohort of 5202 Chinese type 2 diabetic patients recruited between July 1994 and April 2001. RESULTS: The prevalence of the MES was 49.2-58.1% depending on the use of various criteria. There were 189 deaths (men: 100 and women: 89) in these 5205 patients during a median (interquartile range) follow-up period of 2.1 (0.3-3.6 years). Of these, 164 (87%) were classified as cardiovascular deaths. Using the NCEP criterion, patients with MES had a death rate similar to those without (3.51 vs. 3.85%). By contrast, based on the WHO criteria, patients with MES had a higher mortality rate than those without (4.3 vs. 2.4%, p = 0.002). Compared to patients with neither NCEP- nor WHO-defined MES, only the group with MES defined by the WHO, but not NCEP, criterion had significantly higher mortality rate (2.6 vs. 6.8%, p < 0.001). Using Cox regression analysis, only age, duration of diabetes and smoking were identified as independent factors for cardiovascular or total death. Among the various components of MES, hypertension, low BMI and albuminuria were the key predictors for these adverse events. CONCLUSIONS: In Chinese type 2 diabetic patients, the WHO criterion has a better discriminative power over the NCEP criterion for predicting death. Among the various components of the MES defined either by WHO or NCEP, hypertension, albuminuria and low BMI were the main predictors of cardiovascular and total mortality.

Adolescent↗
PubMed2004

Increased leptin concentrations and lack of gender difference in Type 2 diabetic patients with nephropathy.

UNLABELLED: Leptin plays an important role in the regulation of body weight and energy balance. Women have higher circulating leptin level than men. In this study, we examined serum leptin concentrations in Type 2 diabetic men and women with or without nephropathy. Fasting plasma glucose (FPG), lipid profile, and serum leptin concentrations were measured in 34 Type 2 diabetic patients with nephropathy (DMN), 12 normoalbuminuric Type 2 diabetic subjects (DM) and 34 non-diabetic control subjects, all matched for age and body mass index (BMI). RESULT: Patients with diabetic nephropathy had lower high-density lipoprotein cholesterol and higher triglyceride, FPG, urinary albumin/creatinine ratio (ACR) and serum creatinine than the other two groups. There was a significant trend in serum leptin concentrations (P<0.001, analysis of variance ANOVA) across the three groups with the main difference being detected between DMN and control subjects (DMN: 17.5 +/- 16.8 ng/ml, DM: 14.6 +/- 10.5 ng/ml and control: 9.1 +/- 7.1 ng/ml). Women had higher serum leptin concentration than men in the control group (12.5 +/- 7.3 ng/ml versus 4.2 +/- 2.0 ng/ml, P=0.001) and in the DM group (18.9 +/- 11 ng/ml versus 8.6 +/- 5.9 ng/ml, P=0.07) whereas this gender difference was not observed in the DMN group (18.6 +/- 17.0 ng/ml versus 16.8 +/- 17.0 ng/ml, P=0.754). On multivariate analysis, ACR (=0.411, P<0.001) and BMI (=0.240, P=0.002) were independently associated with serum leptin concentrations (R2=0.194, F=22.1, P<0.001) in the whole group. In the DMN group, ACR (=0.370, P=0.016) was the only independent determinant of serum leptin concentrations (R2=0.159, F=11.4, P=0.016). Serum leptin concentrations were higher in Type 2 diabetic patients with nephropathy than normoalbuminuric diabetic patients and controls. Diabetic men with nephropathy had proportionally higher serum leptin such that the gender difference in leptin observed in non-nephropathic individuals was abolished.

Adult↗
PubMed2004

Effects of gender, Helicobacter pylori and hepatitis B virus serology status on cardiovascular and renal complications in Chinese type 2 diabetic patients with overt nephropathy.

BACKGROUND: The aim of this study was to investigate whether chronic infections with Helicobacter pylori and hepatitis B virus (HBV) might affect clinical outcomes in Chinese type 2 diabetic patients with advanced nephropathy. METHODS: A prospective study of 97 type 2 diabetic patients with clinical proteinuria and renal insufficiency (median serum creatinine 200 micro mol/l). RESULTS: During a median follow-up period of 2 years, 34 developed end-stage renal disease (ESRD), 28 had cardiovascular endpoints and 11 patients had died (seven men and four women), and 52.7% developed a combined endpoint. Female patients had longer disease duration, higher blood pressure, lower body weight but higher serum creatinine and spot urine albumin : creatinine ratio as well as lower haemoglobin than male patients. On logistic regression analysis, female gender (hazard ratio: 5.91, p = 0.02), negative H. pylori serology (8.39, p = 0.004), baseline serum creatinine (1.04, p = 0.001) and haemoglobin (1.86, p = 0.01) were independent predictors for ESRD. Systolic blood pressure (1.04, p = 0.003), prior treatment with angiotensin-converting enzyme inhibitors or angiotensin II receptor antagonists (3.41, p = 0.04) and positive hepatitis B surface antigen (4.88, p = 0.025) were independent predictors for cardiovascular endpoints. Female gender (7.89, p = 0.002) and baseline serum creatinine (1.05, p < 0.001) were independent predictors for combined death and cardio-renal endpoints. CONCLUSIONS: In Chinese type 2 diabetic patients with clinical proteinuria renal insufficiency, there were high rates of death and cardio-renal outcomes. Female gender, low haemoglobin and negative H. pylori serology were important predictors for ESRD, whereas chronic HBV infection was associated with increased cardiovascular risks.

Albumins↗
PubMed2003

Hyperkalaemia in a patient with Graves' disease.

A case of hyporeninaemic hypoaldosteronism in a young girl with treated Graves' disease presenting as hyperkalaemia is described. The possible autoimmune link of these two conditions is discussed.

Adult↗
PubMed2002

Asymmetric dimethylarginine (ADMA): a potential link between endothelial dysfunction and cardiovascular diseases in insulin resistance syndrome?

Endothelium-derived nitric oxide plays a major role in the regulation of vascular tone and in the maintenance of vascular homeostasis. Endothelial dysfunction with impaired nitric oxide biosynthesis and decreased bioavailability has been implicated in insulin resistance syndrome and Type II (non-insulin-dependent) diabetes mellitus. Nitric oxide is synthesised by nitric oxide synthase. Asymmetric dimethylarginine is a major endogenous nitric oxide synthase inhibitor. Increased circulating asymmetric dimethylarginine was initially found in patients with chronic renal failure and subsequently many other disease states. Increased asymmetric dimethylarginine plasma concentrations could contribute to the development of insulin resistance and coronary heart disease. Understanding of the pathophysiological role of asymmetric dimethylarginine could lead to novel therapies in the prevention of arteriosclerosis and coronary heart disease.

Animals↗
PubMed2002

Trends in hypertension management in Type I diabetes across Europe, 1989/1990 - 1997/1999.

AIMS/HYPOTHESIS: Our aim was to examine the change in the management of hypertension in patients with Type I (insulin-dependent) diabetes mellitus in Europe, between 1989-1990 and 1997-1999. METHODS: Seven-year changes in hypertension treatment and control (defined as blood pressure <130/85 mmHg) were examined in a large sample of Type I diabetic patients recruited from 26 centres involved in the EURODIAB Prospective Complications Study. Hypertension was defined as a systolic and/or diastolic blood pressure greater than 140 and/or 90 mmHg respectively, and/or use of blood pressure lowering drugs. RESULTS: Of 1866 Type I diabetic patients, 412 had hypertension at baseline and 631 at follow-up. A greater proportion of hypertensive patients were treated at follow-up (69% vs 40%, p<0.0001), which persisted after adjustment for age or centre. Of those who were treated, a modest increase in the proportion of those controlled for hypertension was found (41% vs 32%, p=0.048), which disappeared after adjustment for age. Among hypertensive patients with albuminuria, the proportions treated also increased, from 35% to 76% ( p<0.0001) in microalbuminuric and 64% to 95% ( p<0.0001) in macroalbuminuric patients. Control of hypertension in albuminuric patients did not change significantly and was below 50%. The use of more than one anti-hypertensive drug increased over a 7-year period, from 19% to 33% ( p<0.0001), and a marked increase was shown in the proportion of those taking an ACE inhibitor (from 57% to 82%, p<0.0001). CONCLUSION/INTERPRETATION: The management of hypertension in Type I diabetic patients across Europe has improved over a 7-year follow-up period. Optimal levels of blood pressure treatment and optimal levels of control have not yet been achieved.

Adult↗