Abstract
OBJECTIVE: We evaluated whether measures of glucose dysregulation are associated with subclinical cardiac dysfunction, as assessed by speckle-tracking echocardiography, in an older population. METHODS: Participants were men and women in the Cardiovascular Health Study, age 65+ years and without coronary heart disease, atrial fibrillation, or heart failure at baseline. We evaluated fasting insulin resistance (IR) with the homeostatic model of insulin resistance (HOMA-IR) and estimated the Matsuda insulin sensitivity index (ISI) and insulin secretion with an oral glucose tolerance test. Systolic and diastolic cardiac mechanics were measured with speckle-tracking analysis of echocardiograms. Multi-variable adjusted linear regression models were used to investigate associations of insulin measures and cardiac mechanics. RESULTS: Mean age for the 2433 included participants was 72.0 years, 33.6% were male, and 3.7% were black. After adjustment for age, sex, race, site, speckle-tracking analyst, echo image and quality score, higher HOMA-IR, lower Matsuda ISI, and higher insulin secretion were each associated with worse left ventricular (LV) longitudinal strain and LV early diastolic strain rate (p-value < 0.005); however, associations were significantly attenuated after adjustment for waist circumference, with the exception of Matsuda ISI and LV longitudinal strain (increase in strain per standard deviation increment in Matsuda ISI = 0.18; 95% confidence interval = 0.03-0.33). CONCLUSION: In this cross-sectional study of older adults, associations of glucose dysregulation with subclinical cardiac dysfunction were largely attenuated after adjusting for central adiposity.