Abdominal adiposity largely explains associations between insulin resistance, hyperglycemia and subclinical...

The relative importance of insulin resistance and hyperglycemia to the development of atherosclerosis remains unclear. Furthermore, adiposity may be responsible for observed associations. Our aim was to study the relative contributions of adiposity, insulin resistance and hyperglycemia to subclinical atherosclerosis.

In this cross-sectional analysis of the Netherlands Epidemiology of Obesity (NEO) study, a cohort of persons of 45-65 years, BMI, waist circumference (WC), fasting glucose (FPG), HbA1c and insulin concentrations were measured and the revised HOMA-IR was calculated. The carotid Intima-Media Thickness (cIMT) was measured by ultrasound. We performed linear regression analyses between standardized values of FPG, HbA1c, HOMA-IR, BMI, WC with cIMT, and subsequently included age, sex, ethnicity, education and smoking, HOMA-IR, HbA1c and FPG, BMI and WC in the models.

After exclusion of participants with glucose lowering therapy (n = 356) or missing data (n = 252), this analysis included 6065 participants, 43% men, and mean (SD) cIMT of 616 (92) μm. Differences in cIMT (95% CI) per SD were: FPG: 16 (10,21); HbA1c: 12 (7,16); HOMA-IR: 11 (6,16) μm. These associations attenuated after adjustments, and attenuated most strongly after adjustment for WC. Differences in cIMT (95% CI) per SD in the full model were: FPG: 4 (0,7); HbA1c: 2 (-1,5); HOMA-IR: 0 (-3,3); BMI 16 (13,19); WC: 18 (14,21) μm.

In middle-aged individuals, we observed similar contributions of insulin resistance and hyperglycemia to subclinical atherosclerosis. These contributions were largely explained by abdominal adiposity, emphasizing the importance of weight management.