Insulin resistance and arterial stiffness in healthy adolescents and young adults.

AIMS/HYPOTHESIS: Increased arterial stiffness is a risk factor for adverse cardiovascular events in adults with obesity-related insulin resistance (IR) or type 2 diabetes mellitus. Adolescents with type 2 diabetes have stiffer vessels. Whether stiffness is increased in obesity/IR in youth is not known. We sought to determine if IR was a determinant of arterial stiffness in youth, independent of obesity and cardiovascular risk factors.

METHODS

We measured cardiovascular risk factors, IR, adipocytokines and arterial stiffness (brachial artery distensibility [BrachD], pulse wave velocity [PWV]) and wave reflection (augmentation index [AIx]) in 343 adolescents and young adults without type 2 diabetes (15-28 years old, 47% male, 48% non-white). Individuals <85th percentile of BMI were classified as lean (n = 232). Obese individuals were grouped by HOMA index as not insulin resistant (n = 46) or insulin resistant (n = 65) by the 90th percentile for HOMA for lean. Mean differences were evaluated by ANOVA. Multivariate models evaluated whether HOMA was an independent determinant of arterial stiffness.

RESULTS

Risk factors deteriorated from lean to obese to obese/insulin resistant (all p ≤ 0.017). Higher AIx, lower BrachD and higher PWV indicated increased arterial stiffness in obese and obese/insulin-resistant participants. HOMA was not an independent determinant. Age, sex, BMI and BP were the most consistent determinants, with HDL-cholesterol playing a role for BrachD and leptin for PWV (AIx R²= 0.34; BrachD R² = 0.37; PWV R² = 0.40; all p ≤ 0.02).

CONCLUSIONS/INTERPRETATION: Although IR is associated with increased arterial stiffness, traditional cardiovascular risk factors, especially obesity and BP, are the major determinants of arterial stiffness in healthy young people.