title: The relationship of fasting serum radioimmune insulin levels to incident coronary heart disease in an insulin-treated diabetic cohort.
abstract: It is not known whether insulin levels, in the setting of insulin treatment, are an independent risk factor for coronary heart disease (CHD). We studied a cohort of 116 insulin-treated individuals, 65 yr or older, who were followed for 5.6-9 yr. All were free of CHD at baseline. There were 47 incident CHD events. In Cox proportional hazards modeling, with fasting immune-reactive insulin levels as a continuous variable, the hazard ratio for CHD was statistically significant (P < 0.0001). When insulin levels were divided into intervals, those in the third interval [43-150 microU/ml (258-900 pmol/liter)] had an adjusted 30% increased relative risk (95% confidence interval, 0.57, 2.98) compared with those in the first interval [<20 microU/ml (<120 pmol/liter)]. Those in the fourth interval [151-400 microU/ml (906-2400 pmol/liter)] had an adjusted 5.6-fold increased risk (2.3-13.1; P < 0.0001). Approximately 15% of the cohort had such elevated insulin levels. Immune-reactive insulin levels were strongly correlated with specific insulin, proinsulin, and insulin antibody levels. Markedly elevated fasting immune-reactive insulin levels were an independent risk factor for CHD in this study of insulin-treated older adults. These observational findings should be confirmed through larger prospective studies, given their implications for insulin therapy.
authors.affiliation: Department of Biostatistics, University of Washington, Seattle, Washington 98115, USA. kronmal@u.washington.edu
authors.forename: Richard A
authors.initials: RA
authors.lastname: Kronmal
authors.forename: Joshua I
authors.initials: JI
authors.lastname: Barzilay
authors.forename: Russell P
authors.initials: RP
authors.lastname: Tracy
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Savage
authors.forename: Trevor J
authors.initials: TJ
authors.lastname: Orchard
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Burke
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003327:Coronary Disease / Q000097:blood* / Q000453:epidemiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology*; D005215:Fasting; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000097:blood*; D015994:Incidence; D007328:Insulin / Q000008:administration & dosage / Q000097:blood*; D008297:Male; D011863:Radioimmunoassay; D012307:Risk Factors
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin