Trends in Children's Dietary Inflammatory Index and association with prediabetes in U.S. adolescents.

Background and objectives: Prediabetes is a high-risk state for diabetes. We aimed to illustrate secular trends in the Children's Dietary Inflammation Index (C-DII) among U.S. adolescents and assess its association with prediabetes.

Methods: Adolescents aged 12-18 years were collected from the National Health and Nutrition Examination Survey, 2001-2018. Prediabetes was defined based on Hemoglobin A1c, fasting glucose, and glucose tolerance levels. Risk was quantified by odds ratio (OR) and 95% confidence interval (CI).

Results: A total of 13,684 adolescents were analyzed, representing a weighted total population of 33,351,181. C-DII scores declined significantly from 2001 to 2012 and increased from 2013 to 2018. The relationship between C-DII and prediabetes was roughly linear. When assigning the low C-DII scores as the reference, adolescents with medium and high C-DII scores were 1.22 (adjusted 95% CI: 1.04-1.44) and 1.25 (0.99-1.60) times more likely to have prediabetes. In subgroup analyses, the risk for prediabetes was significantly enhanced in boys (adjusted OR = 1.26 and 1.45 for medium and high C-DII scores, 95% CI: 1.05-1.51 and 1.09-1.92), and in adolescents living in poor families for medium (1.34 and 1.44, 1.08-1.67 and 1.07-1.95).

Conclusions: Our findings indicate a V-shaped secular trend in C-DII scores from 2001 to 2018 in U.S. adolescents, with the nadir in 2011-2012, and the risk for prediabetes was significantly increased by over 20% in adolescents possessing medium or high C-DII scores.