Insulin Resistance and Diabetes in Young Adults and LV Structure and Function in Middle Age

Study Questions:

How do glycemic abnormalities and insulin resistance during young adulthood contribute to left ventricular (LV) structural and functional abnormalities in middle age?

Methods:

Data from 3,179 participants in the 25-year follow-up examination of the CARDIA (Coronary Artery Risk Development in Young Adults) study were analyzed. Subjects were initially classified into four groups: normal glucose tolerance (group 1), impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) (group 2), late-onset diabetes (group 3), or early-onset diabetes (group 4). Latent class trajectory analysis was used to identify patterns in change in insulin resistance among those without diabetes. These groupings were related to echocardiographic parameters of LV structure (mass, relative wall thickness, concentricity [ratio of LV mass:volume]) and function (LV ejection fraction [LVEF], early diastolic filling rate, early diastolic mitral annual velocity, longitudinal and circumferential systolic strain, and early diastolic strain rates).

Results:

Compared to those with normal glucose tolerance, LV mass index was increased in those with early-onset diabetes (11.0 g/m2, p < 0.05), after adjustment for key covariates. Concentricity was increased in IFG/IGT (p < 0.005), late-onset diabetics (p < 0.001), and early-onset diabetics (p < 0.001) compared to normoglycemic subjects. LVEF was reduced in early-onset diabetics compared to normoglycemic subjects (-2.7%, p < 0.005). Longitudinal strain was reduced for all levels of dysglycemia compared to normoglycemia (p < 0.05). Diastolic parameters were also significantly altered in diabetics compared to normoglycemic subjects. Even among normoglycemic subjects, insulin resistance was associated with increased relative wall thickness (p < 0.0001), impaired strain (p < 0.005), and diastolic parameters (p < 0.05).

Conclusions:

The authors concluded that dysglycemia, including without overt diabetes, in early adulthood is associated with adverse LV structural and functional remodeling in middle age.

Perspective:

The CARDIA cohort is unique among large, prospective, longitudinal cohorts in that it has followed a large group of healthy Americans from early adulthood through mid-life. This study demonstrates that dysglycemia even in early adulthood has adverse consequences that are seen in middle age. Much effort in preventive cardiology is focused on middle-aged and older adults. However, the adverse impact of poor metabolic health may already have taken hold at that time. Given unhealthy trends in American behavior during childhood and early adulthood (increased sedentary behavior, decreased exercise), these results are particularly concerning.

Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, CHD & Pediatrics and Arrhythmias, CHD & Pediatrics and Imaging, CHD & Pediatrics and Prevention, Echocardiography/Ultrasound

Keywords: Diabetes Mellitus, Diagnostic Imaging, Diastole, Echocardiography, Glucose Intolerance, Insulin Resistance, Metabolic Syndrome X, Middle Aged, Primary Prevention, Systole, Young Adult, Ventricular Function, Left


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