Long-Term Study Questions Reliability of Impaired Fasting Glucose as an Early Predictor of Diabetes in Young Adults

Published in JAMA Network Open, the study was led by Dr. Abigail R. O. Arons of the University of California, San Francisco, and her team. The analysis was based on data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, which enrolled over 5,000 adults aged 18 to 30 between 1985 and 1986. Participants were followed for three decades to understand long-term glycemic trends.

Using sequence analysis, the researchers identified 1,278 unique glycemic trajectories, which they grouped into nine common patterns. These included stable normoglycemia, five distinct trajectories of IFG that did not lead to diabetes, and three diabetes patterns with onset in early, middle, and later adulthood.

The study revealed the following findings:

• Among the 4,684 eligible participants, 73% were classified into nine common glycemic trajectory patterns.
• Some individuals in the IFG groups experienced temporary elevations in fasting glucose that later returned to normal, occurring around 36 or 47 years of age.
• Other patterns showed sustained low-level IFG beginning in either younger or older adulthood.
• One group had sustained high levels of IFG starting at approximately age 42.
• Three distinct groups progressed to diabetes, with average ages of onset at 35, 44, and 52 years, respectively.
• Many individuals who developed diabetes had not shown signs of impaired fasting glucose in their earlier years.

The researchers emphasized that the wide variation in glycemic progression underscores the need to reconsider the effectiveness of screening strategies that depend solely on IFG. Such strategies, typically developed from data in middle-aged populations, may not adequately reflect the risk profile of younger adults.

While the study offers valuable longitudinal insights, the authors acknowledged several limitations. Follow-up assessments occurred roughly every five years, meaning the exact timing of glucose changes could not be precisely tracked. The study also began when national rates of IFG and diabetes were lower than they are today, affecting the relevance of risk patterns in current populations. Additionally, the cohort comprised only Black and White participants, limiting the generalizability of the findings.

The authors concluded that, despite certain limitations, the study underscores the complex nature of diabetes progression and the need for early-life strategies to identify and manage risk. They emphasized that creating targeted screening tools and prevention efforts specifically designed for young adults could help bridge a significant gap in public health.

The researchers advocate for broader, more refined approaches that move beyond traditional IFG-based screening for more effective detection and prevention of type 2 diabetes in younger populations.

Reference:

Arons ARO, Pacca L, Jacobs DR, Vable A, Schillinger D. Thirty-Year Glycemic Trajectories From Young Adulthood Through Middle Age. JAMA Netw Open. 2025;8(6):e2517455. doi:10.1001/jamanetworkopen.2025.17455