Abstract Body: Introduction
Young adulthood is increasingly recognized as an important window for diabetes prevention. While lifestyle interventions and pharmacotherapy are available to young adults, early identification of those at risk of diabetes progression is essential to targeted prevention. Diabetes risk progression has been extensively studied in other age groups, but it is unknown whether younger adults with prediabetes have similar risk of progression. Long-term studies of diabetes outcomes from young adulthood can fill this gap.

Objective
To characterize 35-year diabetes incidence among young adults in a diverse population-based cohort by baseline glycemic status and risk scores.

Methods
The Coronary Artery Risk Development in Young Adults (CARDIA) study followed a cohort of individuals aged 18-30 at enrollment, with balanced subgroups of race (Black and White), gender, and education level, in 4 US cities. Individuals had 8 glycemic examinations from 1985-1986 through 2020-2022. We determined diabetes incidence density, cumulative incidence, and Kaplan-Meier survival, by baseline glycemic status (normoglycemia or impaired fasting glucose [IFG]) and ADA-CDC Prediabetes Risk Test scores (“high-risk” defined >=4; score components gender, BMI, family history, physical inactivity, hypertension).

Results
We followed 4985 participants for a median 30.1 years (Table 1). Overall diabetes incidence density was 21.2 cases per 3500 person-years (21.2 cases/100 individuals in 35 years; cumulative incidence 16%), and 58.8 cases for baseline IFG (n=101; cumulative incidence 38%). Individuals with both IFG and high-risk score had highest incidence (123.8 cases; cumulative incidence 73%), followed by baseline normoglycemia and high-risk score (67.5 cases; cumulative incidence 43%) then IFG and low-risk score (48.5 cases; cumulative incidence 31%). (Table 2; Fig 1)

Conclusions
35-year diabetes incidence among young adults with IFG was lower than prior long-term studies in middle-aged cohorts. Those with IFG with high-risk scores had highest incidence, and baseline normoglycemia with high-risk scores had higher incidence than IFG overall or IFG with low-risk scores. These findings support increased use of risk-assessment tools in young adults, lowering the threshold for ADA-CDC Prediabetes Risk Test from 5 to 4 for young adults (for Diabetes Prevention Program eligibility), and highlight a need for validated, young adult-specific diabetes risk screening approaches.