Examining trends in prediabetes and its relationship with the metabolic syndrome in US adolescents, 1999-2014

Abstract

Aims: We sought to investigate temporal trends in prediabetes prevalence among US adolescents using two definitions and evaluate relationships with obesity and a MetS-severity score.

Methods: We evaluated data from 5418 non-Hispanic white, non-Hispanic black, and Hispanic adolescents aged 12-19 participating in the National Health and Nutrition Examination Survey 1999-2014 with complete data regarding MetS and hemoglobin A1c (HbA1c). Prediabetes status was defined by American Diabetes Association (ADA) criteria: fasting glucose 100-125 mg/dL or HbA1c 5.7%-6.4%. MetS severity was assessed with a MetS-severity Z-score.

Results: Prevalence of prediabetes as defined by HbA1c abnormalities significantly increased from 1999-2014, while prevalence of prediabetes as defined by fasting glucose abnormalities showed no significant temporal trend. There were variations in these trends across different racial/ethnic groups. MetS Z-score was overall more strongly correlated with HbA1c, fasting insulin, and the homeostasis model of insulin resistance than was BMI Z-score. These correlations were true in each racial/ethnic group with the exception that in non-Hispanic white adolescents, in whom the MetS Z-score was not significantly correlated with HbA1c measurements.

Conclusion: We found conflicting findings of temporal trends of US adolescent prediabetes prevalence based on the ADA's prediabetes criteria. The increasing prevalence of prediabetes by HbA1c assessment is concerning and raises the urgency for increased awareness and appropriate measures of prediabetes status among physicians and patients.

Keywords: Insulin resistance; Metabolic syndrome; Obesity; Prediabetes; Type 2 diabetes mellitus.

Figures

Figure 1. Prediabetes prevalence versus time

The bars show weighted frequency prediabetes with 95% confidence intervals as determined by either fasting glucose or HbA1c, adjusted for age and sex. Logistic regression analysis showed that odds of having HbA1C prediabetes was increasing over time (odds ratio reported in figure). There were no temporal trends in fasting glucose prediabetes prevalence.

Figure 2. Correlation of fasting insulin and HbA1c measurements with the MetS Z-score and the BMI Z-score

Fasting insulin (log-transformed) and HbA1C are both significantly positively correlated with the overall U.S. adolescent population. MetS Z-score analyses yielded higher slopes than BMI Z-score analyses.