Population-based studies determining the prevalence of type 2 diabetes in adolescents are sparse. Therefore, we designed a feasibility population-based study to detect postprandial hyperglycemia, an early manifestation of diabetes, in adolescents.
The study population consisted of all students taking a mandatory sophomore health class at a suburban Chicago high school during the 1998–1999 school year. Those who returned parental consent, student assent, and a parental questionnaire entered the study. Within 90–120 min of completing a standardized lunch (∼100 g carbohydrate), students had a capillary blood glucose (CBG) exam for acanthosis nigricans (AN), as well as height and weight measurements. Study was approved by the institutional review board and the school board.
Of 553 students, 284 (51%) enrolled and 255 (90%) completed the study. The ethnic profile of our sample (46% Caucasian, 38% African American, and 6% Hispanic) closely paralleled that of the school. The mean age was 15.9 ± 0.5 years; 53% were female; 38% had a first- or second-degree relative with diabetes; 3% had maternal gestational diabetes; and 27% had BMI ≥85th percentile. Mean CBG was 5.1 ± 0.7 mmol/l.
Postprandial CBG was significantly associated with BMI ≥85th percentile (P < 0.01) and a first-degree relative with diabetes (P = 0.001). However, these two factors only accounted for 6% of the variation in CBG (R2 = 0.06).
Prevalence of AN in African American, Hispanic, and Caucasian students was 51, 25, and 1%, respectively. AN was significantly associated with a first- or second-degree relative with diabetes (P = 0.004), ethnicity (P < 0.001), and BMI ≥85th percentile (P < 0.001).
No postprandial CBG was ≥7.8 mmol/l. The absence of undiagnosed hyperglycemia is consistent with findings of the Third National Health and Nutrition Examination Survey (2) and speaks against population-based studies. Limiting screening to high-risk individuals may better improve efficacy and feasibility.
Recently Sinha et al. (3) reported the prevalence of impaired glucose tolerance in obese Caucasian and African American adolescents to be 16 and 27%, respectively, and undiagnosed diabetes in African American teens to be 8%. The absence of hyperglycemia in our obese subjects (including 6 Caucasian and 17 African American) may be due to ascertainment bias, given small sample size, or because teens with a postprandial CBG <7.8 mmol/l may still have abnormal glucose tolerance.
Interestingly, our results suggest that a normal but higher CBG is associated with adult risk factors for type 2 diabetes. We propose that subtle abnormalities in glucose homeostasis may present in adolescence and then track with the development of overt abnormalities in adulthood.
Article Information
This study was funded by the Lilly Fellowship Training Grant.
We gratefully acknowledge Julie Calwell, Diane Ragalie, John Wilson, and Medisense for testing materials.
References
Address correspondence to Dr. Wendy Brickman, Children’s Memorial Hospital, 2300 Children’s Plaza mail code no. 54, Chicago, IL 60091. E-mail: [email protected].
