Abstract 64: Risk Factors for Carotid Artery Lipid Deposition Measured by Gray Scale Median of the Intima-Media in Children and Young Adults Over the Life Course

Introduction: Echogenicity of the carotid arterial wall, measured by gray scale median of the intima-media (GSM-IM), is a unitless measure that reflects lipid deposition in the arterial wall, with lower values indicating greater lipid deposition and atherosclerosis. Due to the relative novelty of GSM-IM, its progression and associated risk factors are incompletely understood. This study investigated the GSM profile in childhood and young adulthood using a longitudinal cohort of individuals followed over time, and conducted a priori analysis on the behavioral, psychosocial, and health risk factors for GSM. Methods: Data were collected as part of the Meta-Air2 follow-up study of participants enrolled in the Southern California Children’s Health Study. A total of 240 study participants underwent a carotid artery ultrasound examination in 2008 (mean age±standard deviation [ SD] : 11.2±0.6 years), and again between 2018 and 2023 (24.2±1.6 years) to assess changes in carotid artery health, including GSM-IM, carotid artery intima-media thickness (CIMT), and carotid artery distensibility. Participants self-reported lifestyle behaviors, psychosocial health, and underwent anthropometric and blood pressure measures at both time points. Mixed effects models were used to predict GSM-IM changes with repeated measurements of lifestyle behaviors, perceived stress, BMI, and blood pressure. Results: Means and SDs of GSM-IM were 110.0±27.4 in childhood, and 75.6±15.8 in adulthood, with an annual change rate of -2.6 per year. Individuals of Hispanic ethnicity, and those with lower parental education levels had significantly lower GSM-IM in both childhood and adulthood. GSM-IM was significantly correlated with other measures of carotid artery atherosclerosis, including CIMT (r=0.28; p <0.001) and carotid artery distensibility (r=0.36; p <0.001). Results of mixed effects models adjusting for covariates, indicated that higher BMI (β=-1.35; 95% confidence interval [CI], -1.70, -0.99; p <0.001) and systolic blood pressure (β=-0.32, 95% CI, -0.55, -0.09; p=0.007) were significantly associated with lower GSM-IM. A significant interaction between BMI and age (β difference=0.14; 95% CI, 0.09, 0.20; p <0.001) suggested that a per-unit change in BMI has a greater effect on GSM-IM among adolescents compared to young adults. Health compromising behaviors, including less sleeping time, smoking, drug use, and higher perceived stress were significantly associated with lower GSM-IM in unadjusted models. However, these associations were attenuated after adjustment for covariates. Conclusion: Our study highlights the influence of BMI, particularly during childhood, blood pressure and lifestyle behaviors on adverse changes in GSM-IM, indicative of greater lipid deposition. These risk factors may be key targets for early prevention for atherosclerosis.