Direct and indirect effects of obesity on progression of carotid arterial injury in youth

OBJECTIVE: Increased carotid intima-media thickness (cIMT) is associated with cardiovascular (CV) events in adults and with elevated CV risk factors in youth. The aim of this study was to determine whether obesity has an direct or indirect association with cIMT. METHODS: Structural equation modeling was used to elucidate pathways for obesity to change cIMT. Complete data were collected twice on 294 participants (mean age 17.5 years, 16% with type 2 diabetes). Latent baseline and follow-up cIMT, BMI, and CV risk factors were analyzed with SAS 9.4. Model fit was assessed. RESULTS: There were increases in BMI, mean arterial pressure (MAP), low-density lipoprotein cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, C-reactive protein, and glucose and a decrease in insulin and glycosylated hemoglobin over 5 years (all p < 0.05). Only bulb (0.031 mm) and internal (0.027 mm) cIMT increased (all p < 0.001). Significant direct effects on cIMT change were baseline MAP (β 0.23), BMI z score (β 0.16), change in glucose (β 0.37), and age (β 0.37; all p < 0.05). Change in MAP showed a trend (β 0.14, p = 0.10). BMI also had a significant indirect effect (β 0.17), whereas non-HDL demonstrated no significant effect. CONCLUSIONS: Baseline adiposity drives increasing blood pressure and glucose in high-risk youth leading to accelerated accumulation of carotid arterial injury. Prevention of acquisition of obesity in youth is critical in slowing development of CV disease.