Normal Childhood Body Mass Index and Glucose Level Predictors for Type 2 Diabetes in Adulthood

child standing on scale
child standing on scale
Childhood BMI, fasting glucose, and insulin in relation to incident adult type 2 diabetes mellitus were examined.

Body mass index (BMI) and fasting glucose levels considered normal in children may be predictors of developing type 2 diabetes mellitus (T2DM) as an adult, according to results from a prospective longitudinal study published in Diabetes Care.

Data from The International Childhood Cardiovascular Cohort Consortium, a collaboration of 7 long-standing cohort studies collected on 3 continents, were used for this study. Children and adolescents (aged 3-19 years) were recruited from 1970 to 1990 for baseline assessment; a total of 6738 participants were followed up from 2015 to 2019.

The majority of study participants did not have T2DM at follow-up (93.5%). The participants with T2DM were significantly older (mean, 48.0 vs 43.8 years; P <.001), more were women (P =.011), and were more likely to be Black (P <.001).

After adjusting for possible cofactors, developing T2DM was significantly associated with childhood BMI (hazard ratio [HR], 1.55; 95% CI, 1.44-1.67; P <.001) and glucose level (HR, 1.24; 95% CI, 1.13-1.35; P <.001). The investigators combined BMI and glucose to develop a risk score model and observed a stronger predictor for T2DM (HR, 1.87; 95% CI, 1.72-2.05; P <.001).

Using the BMI-glucose risk score, the investigators interrogated rates of T2DM by age. They observed that beginning at 30 years of age, individuals with a risk score ³1 had an increased risk for T2DM. At ages 40 and 50 years, individuals with a risk score >1 had a 15% and 28% increased risk, respectively.

A risk score of 1 coincided with a mean BMI between the 85th and 95th percentiles and absolute glucose level between 88.4 to 99.4 mg/dL. Both these levels fall outside what the Centers for Disease Control and Prevention has defined as obese.

The investigators observed that the natural log of insulin level was similarly correlated with T2DM (HR, 1.34; 95% CI, 1.16-1.56; P <.001). Adding ln(insulin) to BMI and glucose, they developed an additional risk score (HR, 2.38; 95% CI, 2.08-2.73; P <.001).

This study was possibly limited by 2 factors, the researchers allowed. The observational design of this study did not allow for the investigators to control for puberty which may increase insulin resistance. To try and account for this factor, participants were stratified by age, however some bias may still be present in the data. Most (6/7) cohorts used self-reported rates of T2DM. Self-reporting may have led to an under estimation.

The conclusion drawn from these data was that childhood BMI and glucose may predict risk for adulthood T2DM and that these risky levels fall within what current guidelines define as the normal range. These data also indicated that insulin levels have the potential to be a predictor, if insulin assessment were standardized.


Hu T, Jacobs D R, Sinaiko A R, et al. Childhood BMI and Fasting Glucose and Insulin Predict Adult Type 2 Diabetes: The International Childhood Cardiovascular Cohort (i3C) Consoritum. Diabetes Care. 2020;dc200822. doi:10.2337/dc20-0822