Association of insulin resistance to electrocardiographic changes in non obese asian indian subjects with hypertension

Abstract

To investigate the relationship between insulin resistance and electrocardiographic changes in hypertension in the absence of confounding influences, plasma glucose and insulin responses to oral glucose were studied in 26 normotensive and 38 hypertensive subjects. Resting ECG was taken and classified into normal or abnormal using the Minnesota code. Among the 38 subjects, 16 had ECG abnormalities. All the hypertensive subjects had normal glucose tolerance. Serum insulin response of hypertensive subjects with ECG changes was 43% higher than those of hypertensive subjects without ECG changes and of normotensive subjects. The ratio AUC glucose/AUC insulin, a measure of insulin sensitivity was significantly reduced in subjects with abnormal ECG. Serum LDL cholesterol was significantly elevated and was the highest in hypertensive subjects with abnormal ECG. The ratio, Total Cholesterol/HDL Cholesterol was elevated to 5.81+/-0.47. I(125)-insulin binding to erythrocytes from 6 normotensive subjects, and 16 hypertensive subjects (8 with and 8 without ECG abnormalities) indicated 50% reduction in insulin receptor number in both the groups of hypertensive subjects compared to normotensive subjects. Multiple logistic regression analysis using mean blood pressure, serum total cholesterol, LDL cholesterol/HDL cholesterol, sex, insulin level at 60 min in OGTT, treatment, serum triglyceride, presence of family history of diabetes, CHD, hypertension and tobacco as independent variables causing ECG changes, revealed correct classification in 84% of cases. Among the variables, insulin level in OGTT contributed the most to ECG abnormalities. The data suggest that in the non obese, non diabetic Asian Indian hypertensive subjects, the presence of electrocardiographic abnormalities might be partly related to hyperinsulinemia or insulin resistance in them.

Insulin resistance in obese hypertensive Asian Indian subjects

“…This age difference between nonobese subjects in the present study and in our previous studies could play a role in causing the different levels of hyperinsulinaemia in the present study. In the present study, hyperinsulinaemia was seen in both the basal state and in the OGTT, whereas in our previous studies on nonobese subjects, 10,11 hyperinsulinaemia was observed only during OGTT. It is not unlikely that hypertension and obesity in¯uence postglucose insulin concentrations independently and possibly confound each other when both are present in the same individual.…”

“…We had previously demonstrated the effect of hypertension in causing hyperinsulinaemia in nonobese subjects. 10,11 In the present study, we determined the effect of obesity in normotensive subjects and hypertensive subjects. As a result, the nonobese hypertensive subjects chosen to match the obese group are younger compared to nonobese normotensive subjects (46.9 y vs 55.2 y, Table 1) and both these subjects are still younger compared to nonobese subjects in the previous studies 10,11 (aged 58.6 ± 63.8 y).…”

“…10,11 In the present study, we determined the effect of obesity in normotensive subjects and hypertensive subjects. As a result, the nonobese hypertensive subjects chosen to match the obese group are younger compared to nonobese normotensive subjects (46.9 y vs 55.2 y, Table 1) and both these subjects are still younger compared to nonobese subjects in the previous studies 10,11 (aged 58.6 ± 63.8 y). This age difference between nonobese subjects in the present study and in our previous studies could play a role in causing the different levels of hyperinsulinaemia in the present study.…”

“…Subsequently, we had reported that among the nonobese hypertensive subjects, only those subjects with hyperinsulinaemia had abnormal electrocardiographic changes. 11 Asian Indian subjects are generally lean and the prevalence of obesity is not higher than in other populations. However, incidence of obesity among hypertensive subjects is similar to other populations.…”

Body mass index and obesity-related metabolic disorders in Taiwanese and US whites and blacks: implications for definitions of overweight and obesity for Asians

“…Attention has been given to the adverse health consequences of a moderate increase in body mass index (BMI) in different ethnic groups (2). For example, it was suggested that a moderate increase in BMI makes South Asians more prone to insulin resistance and related diseases (3)(4)(5)(6)(7).…”