Association of hypertension with cluster of insulin resistance syndrome factors: the Chennai Urban Population Study (CUPS-12)

Abstract

The objective of this study was to investigate the association of insulin resistance and the cluster of insulin resistance syndrome (IRS) factors with hypertension in a native urban population from southern India. The Chennai Urban Population Study (CUPS) is an epidemiological study involving two residential areas in Chennai in southern India. Of the total of 1399 eligible subjects (age ≥20 years), 1262 (90.2%) participated in the study. Subjects were classified as hypertensives if they had systolic blood pressure (SBP) ≥140 mmHg or diastolic blood pressure (DBP) ≥90 mmHg, if they were known hypertensives, or if they were receiving treatment with antihypertensive drugs. Insulin resistance was computed using the homeostasis model assessment (HOMA IR). The overall prevalence of hypertension in the population was 22.1%. Prevalence of hypertension increased with an increase in quartiles of fasting insulin levels (p=0.035) and HOMA IR (p=0.03). Logistic regression analysis revealed that HOMA IR was significantly associated with hypertension, which was not altered even after addition of risk factors like age, smoking habit and alcohol consumption into the model. However, inclusion of variables associated with IRS abolished the association of insulin resistance with hypertension. Factor analysis identified four factors: factor 1 had positive loading of body mass index, age, systolic and diastolic blood pressures; factor 2 had positive loading of HOMA IR, fasting plasma glucose, triglycerides and body mass index; factor 3 had positive loading of waist-hip ratio, triglycerides and smoking habit and negative loading of alcohol consumption; factor 4 was loaded with age and serum cholesterol. Factor 1, the hypertension factor loaded with systolic and diastolic blood pressures, shared a correlation with the insulin resistance cluster through body mass index. Our results suggest that the “insulin resistance cluster” is associated with hypertension in this urban population of southern India.