title: Presence of hypertension modifies the impact of insulin resistance on incident cardiovascular disease in a Middle Eastern population: the Tehran Lipid and Glucose Study.
abstract: OBJECTIVE
  To examine the independent impacts of the homeostasis model assessment of insulin resistance (HOMA-IR) and the updated model (HOMA2-IR) on incident cardiovascular /coronary heart disease in a Middle Eastern population with a high prevalence of cardiovascular disease risk factors.
  
  
  METHODS
  We examined 3777 Iranian people, aged ≥ 30 years, without history of cardiovascular disease and without use of antidiabetic medication at baseline. Both HOMA-IR and HOMA2-IR were log-transformed and categorized into quartiles. The multivariable Cox proportional hazard regression model, adjusted for traditional cardiovascular disease risk factors, was applied to examine the association between HOMA-IR/HOMA2-IR with incident cardiovascular/coronary heart disease, considering the lowest quartile as reference.
  
  
  RESULTS
  During a median follow-up of > 10 years, 197 cardiovascular disease and 181 coronary heart disease events occurred. Among the covariates, we found a significant interaction between hypertension and HOMA-IR/HOMA2-IR for incident coronary heart/cardiovascular disease (all P ≤ 0.01). Among the population without hypertension, the risk of cardiovascular disease significantly increased in the second [hazard ratio 1.96 (95% CI 1.04-3.68)], third [hazard ratio 1.93 (95% CI 1.00-3.75)] and fourth [hazard ratio 2.34 (95% CI 1.15-4.75)] quartiles of HOMA-IR, and the risk of coronary heart disease increased significantly in the fourth quartile of HOMA-IR [hazard ratio 2.30 (95% CI 1.12-4.73)], but no significant association was detected between HOMA-IR and cardiovascular/coronary heart disease in the population with hypertension. Among the populations both with and without hypertension, no risk was found to be associated with HOMA2-IR quartiles however, a 1-unit increase in HOMA2-IR was associated with a significant risk of cardiovascular disease among the non-hypertensive group [hazard ratio 1.60 (95% CI 1.03-2.48); P = 0.03].
  
  
  CONCLUSIONS
  The presence of hypertension modified the impact of HOMA-IR/HOMA2-IR on incident cardiovascular/coronary heart disease. The presence of insulin resistance highlighted a significant and independent risk for cardiovascular disease/coronary heart disease only in the population without hypertension.
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Ghoreishian
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Tohidi
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: A
authors.initials: A
authors.lastname: Derakhshan
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Hajsheikholeslami
authors.affiliation: Endocrine Research Centre, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Azizi
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: S
authors.initials: S
authors.lastname: Kazempour-Ardebili
authors.affiliation: Prevention of Metabolic Disorders Research Centre, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Hadaegh
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000378:metabolism; D015331:Cohort Studies; D015987:Effect Modifier, Epidemiologic; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000378:metabolism; D015994:Incidence; D007333:Insulin Resistance; D007492:Iran / Q000453:epidemiology; D050356:Lipid Metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D008877:Middle East / Q000453:epidemiology; D012307:Risk Factors
chemical_list: D001786:Blood Glucose; D008055:Lipids