Visceral & subcutaneous abdominal fat in relation to insulin resistance & metabolic syndrome in non-diabetic south Indians.

Background & objectives: The objective of the study was to determine whether visceral or subcutaneous component of abdominal fat was associated with insulin resistance and metabolic syndrome in non-diabetic Asian Indians. Method: This cross-sectional study had on 120 individuals with normal glucose tolerance (49 males and 71 females). A single slice CT scan at L4- L5 was done for measurement of visceral and subcutaneous abdominal fat. Metabolic syndrome was defined according to the South Asian Modified National Cholesterol Education Program Adult Treatment Panel III criteria (SAM-NCEP) criteria. Insulin Sensitivity Index (ISI-Matsuda) was used to assess insulin sensitivity/resistance. Results: Linear regression analysis revealed that visceral, but not subcutaneous fat was associated with serum triglycerides (R2=0.457, β= 0.34; P=0.006), HDL cholesterol (R2=0.430, β= -0.051; P=0.018) and ISI-Matsuda (R2=0.437, β= -0.05; P=0.039) after adjusting for age, gender and BMI. Visceral fat showed significant association with metabolic syndrome (OR: 1.013, 95% CI: 1.001- 1.025; P=0.041) even after adjusting for age, gender, body mass index and glycated haemoglobin whereas subcutaneous fat did not show such an association. Interpretation & conclusions: These results indicate that in non-diabetic Asian Indians, visceral, but not subcutaneous component of abdominal fat is associated with insulin resistance, cardiovascular risk factors and metabolic syndrome.

Accelerated platelet activation in Asian Indians with diabetes and coronary artery disease--The Chennai Urban Population Study (CUPS-13).

AIM : To assess platelet activation in south Indian type 2 diabetic subjects with and without CAD. METHODS : Four groups of subjects were studied; Group 1 comprised of non-diabetic subjects without coronary artery disease (CAD) (n = 30). Type 2 diabetic subjects without CAD formed Group 2 (n = 30); Group 3 comprised of type 2 diabetic subjects with CAD (n = 30) and Group 4 consisted of non- diabetic subjects with CAD (n=14). CAD was diagnosed based on coronary angiographic evidence of severe double or triple vessel disease. Platelet activation was tested after an overnight fast in blood obtained from a bleeding wound at 1 minute post-incision (wound-induced activation) as well as venous blood stimulated in vitro with collagen, using whole blood flow cytometry. In subjects with CAD, aspirin was withdrawn for 7 days and nitrates for 24 hours. RESULTS: Collagen induced GP IIb/IIIa binding was significantly higher among diabetic subjects with (28.10 +/-19.89; p<0.05) and without CAD (21.02+/-19.62; p<0.05) and non-diabetic subjects with CAD (23.89+/-15.65; p<0.05) compared to non-diabetic subjects without CAD (11.69+/-13.69). Regression analysis showed collagen induced GP IIb/IIIa binding to be significantly associated with CAD [odds ratio (OR): 1.029, p = 0.025] and diabetes (OR: 1.037, p = 0.007). CONCLUSION: Increased platelet activation is seen in urban south Indians with diabetes and CAD.

Association of small dense LDL with coronary artery disease and diabetes in urban Asian Indians - the Chennai Urban Rural Epidemiology Study (CURES-8).

OBJECTIVE: Earlier studies in Europeans have identified small dense LDL to be associated with coronary artery disease and diabetes. In this study we assessed the association of small dense LDL with diabetes and CAD in Asian Indians. METHODS: Study subjects were selected from the Chennai Urban Rural Epidemiology Study (CURES), a population based study on representative sample of Chennai city in southern India. Group 1:non-diabetic subjects (n = 30); Group 2: diabetic subjects without CAD (n = 30); Group 3:diabetic subjects with CAD (n = 30). LDL subfractions were estimated using LipoPrint LDL system. LDL subfractions 3 and above, defined as small dense LDL was summed up to determine the overall small LDL. 75th percentile of the overall small dense LDL in non-diabetic subjects was used as a cut-off for defining elevated levels of small dense LDL. RESULTS: The mean age of the study subjects was not significantly different among groups. Overall small dense LDL was significantly higher in diabetic subjects with CAD (16.7 +/- 11.1 mg/dl, p < 0.05) and without CAD (11.1 +/- 8.0 mg/dl, p < 0.05) compared to non-diabetic subjects without CAD (7.2 +/- 6.8 mg/dl). Small dense LDL showed a positive correlation with fasting plasma glucose (r = 0.252, p = 0.023), HbA1c (r = 0.281, p = 0.012), total cholesterol (r = 0.443, p < 0.001), triglycerides(r = 0.685, p < 0.001), LDL(r = 0.342, p = 0.002), total cholesterol/HDL ratio (r = 0.660, p = < 0.001) and triglycerides/HDL ratio(r = 0.728, p < 0.001) and a negative correlation with HDL cholesterol (r = -0.341, p = 0.002) and QUICKI values (r = -0.260, p = 0.019). ROC curves constructed to predict elevated small dense LDL ((9.0 mg/dl) revealed that triglycerides/HDL ratio and total cholesterol/HDL ratio had higher AUC values compared to other parameters. A triglycerides/HDL ratio of 3.0 had the optimum sensitivity (80.0%) and specificity (78.0%) for detecting elevated small dense LDL. CONCLUSION: This data suggests that in Asian Indians, small dense LDL is associated with both diabetes and CAD and that a triglycerides/HDL ratio (3.0 could serve a surrogate marker of small dense LDL.

Relationship of tissue plasminogen activator, plasminogen activator inhibitor-1 and fibrinogen with coronary artery disease in South Indian male subjects.

AIM: Prevalence rates of coronary artery disease (CAD) are reported to be very high in Asian Indians. Conventional risk factors do not explain the high rates of CAD among Indians. Recently, several newer risk factors have been reported to be associated with CAD. We measured tissue plasminogen activator (tPA) antigen, plasminogen activator inhibitor-1 (PAI-1) and fibrinogen levels in South Indian diabetic and non-diabetic subjects with and without CAD. METHODS: Four groups of subjects were studied (all males); Group 1 comprised of non-diabetic subjects without CAD (n=50). Non-diabetic subjects with CAD formed group 2 (n=50); group 3 comprised of type 2 diabetic patients without CAD (n=50) and group 4 consisted of type 2 diabetic patients with CAD (n=50). CAD was diagnosed based on coronary angiographic evidence of severe double or triple vessel disease. RESULTS: Both diabetic and non-diabetic patients with CAD had significantly higher levels of tPA, PAI-1 and fibrinogen compared to non-diabetic without CAD (p < 0.05). Patients with CAD were distributed more in the upper tertiles of these risk factors compared to those without CAD. A strong association between tPA and PAI-1 was noted in the Pearson's correlation analysis (p < 0.001). Univariate regression analysis showed tPA (Odds ratio--1.12, p = 0.03), PAI-1 (Odds ratio--1.03, p = 0.008), fibrinogen (Odds ratio--1.01, p < 0.0001), serum cholesterol (Odds ratio--1.008, p = 0.04) and hypertension (Odds ratio--3.7, p = 0.0001) to be associated with CAD. Multiple logistic regression analysis revealed hypertension (Odds ratio--4.6, 95% confidence interval--2.113-9.950, p = 0.0001) and fibrinogen (Odds ratio--1.012, 95% confidence interval--1.007-1.018, p = 0.0001) as risk factors for CAD. CONCLUSION: Our study suggests that prothrombogenic risk factors particularly fibrinogen may be associated with CAD in South Indians.

Absence of association between serum homocysteine levels and coronary artery disease in south Indian males.

BACKGROUND: Asian Indians are reported to have a very high prevalence of premature coronary artery disease. However, traditional risk factors do not explain this excess of coronary artery disease. Elevated levels of homocysteine are reported to be associated with coronary artery disease among Europeans. This study looked at the association of serum homocysteine levels with coronary artery disease in South Indians. METHODS AND RESULTS: Four groups of patients were studied: Group 1 consisted of healthy nondiabetic subjects without coronary artery disease (n=18): Group 2 consisted of nondiabetic subjects with coronary artery disease (n=21); Group 3 consisted of type 2 diabetic patients without coronary artery disease (n=18) and Group 4 consisted of type 2 diabetic patients with coronary artery disease (n=20). The mean homocysteine value was 12.4+/-3.4 micromol/L in Group 1; 12.6+/-4.6 micromol/L in Group 2; 10.1+/-4.4 micromol/L in Group 3; and 10.4+/-3.9 micromol/ L in Group 4. There was no significant difference in the homocysteine levels between the groups studied. The prevalence of hyperhomocysteinemia, defined as a level of 17.1 micromol/L (the 95th percentile for serum homocysteine in the control group) was not significantly different among the groups. CONCLUSIONS: Elevated serum homocysteine levels are not associated with coronary artery disease in South Indian male subjects with or without diabetes. However, the results must be interpreted with caution because of the small numbers studied.