The association between adapted dietary index for gut microbiota and carotid intima-media thickness among overweight or obese children and adolescents.

Childhood obesity is associated with early vascular alterations that can be assessed by carotid intima-media thickness (cIMT). The dietary index for gut microbiota (DI-GM) was developed to reflect dietary patterns supportive of microbial diversity, but its use in pediatric populations has not been established. This study investigated the association between an adapted DI-GM (aDI-GM) and cIMT among children and adolescents with overweight or obesity. In this cross-sectional analysis, 354 participants aged 7-18 years were included. Dietary intake was assessed using a validated 147-item food frequency questionnaire, and an adapted 12-component DI-GM was calculated based on available dietary data. Carotid IMT was measured using high-resolution ultrasonography and categorized into tertiles, with the highest tertile defined as high cIMT. Associations were examined using multivariable linear and logistic regression models, adjusted sequentially for demographic, anthropometric, biochemical, lifestyle, and dietary factors. In tertile-based analyses, no statistically significant associations with cIMT were observed. In continuous analyses, higher aDI-GM scores were inversely associated with the odds of high cIMT in the fully adjusted model; specifically, each one-unit increase in aDI-GM was associated with lower odds of high cIMT (OR = 0.79, 95% CI: 0.68-0.92, p < 0.01). These findings differed according to modeling approach and should therefore be interpreted cautiously. Given the cross-sectional design and the exploratory application of an adult-derived index in a pediatric population, these findings should be considered hypothesis-generating and require confirmation in longitudinal studies.