Abstract 2807: Associations of Insulin Metabolism and Diabetes with Cardiac Magnetic Resonance Measures of Ventricular Structure are Mediated by Clinical Risk Factors: the National Heart, Lung and Blood Institute’s Framingham Heart Study
Background: Prior literature on the relationship of diabetes and subclinical abnormalities in insulin/glucose with abnormal cardiac structure and function using M-mode and 2D echocardiography are conflicting. Cardiovascular magnetic resonance (CMR) affords more accurate, volumetric measurements and may help clarify these relations.
Methods: In 1603 attendees (55% women) of Framingham Offspring Cohort examination cycle 7, we contemporaneously measured glycemic indices and cardiac measures using CMR. We used sex-specific age and multivariable adjusted analysis of covariance (ANCOVA) to relate insulin resistance (homeostasis assessment model - insulin resistance; HOMA-IR), pre-diabetes (fasting glucose 100–125mg/dl; fasting insulin ≥ 75th percentile) and diabetes to left ventricular mass (LVM) indexed to height 2.7 and LVM to LV end diastolic volume ratio (LVM/LVEDV).
Results: In both men and women, cardiac measures (adjusted for age) increased with increasing HOMA-IR (regression coefficients β = 1.76 and 1.48 per SD of HOMA for men and women respectively; p<0.0001 for both), but adjustment for covariates (including body-mass index, systolic BP and smoking) rendered this relation nonsignificant. LVM and LVM/LVEDV were higher in participants with pre-diabetes and diabetes (in both sexes) in age-adjusted models (Table 1⇓), but not in multivariable adjusted models. In stepwise models, the relation of insulin indices with cardiac measures was nonsignificant after addition of BMI.
Conclusion: Abnormalities in insulin/ glucose metabolism are related to changes in cardiac structure and function, but these relations appear to be mediated by co-existing risk factors, primarily BMI.