Insulin Resistance, Depression, and the Progression to Type-2 Diabetes in Youth

Abstract

ABSTRACT Childhood obesity has become epidemic in the United States. Coinciding with this rapid increase in obesity is the development of type-2 diabetes in youth. Little is known about the progression of insulin resistance to type-2 diabetes or association of depressive symptoms and impaired glucose metabolism in at-risk obese youth. A retrospective chart review and a secondary data analysis was done using a descriptive correlational design exploring the incidence of insulin resistance, hyperinsulinemia, impaired fasting glucose, impaired glucose tolerance, and progression to type-2 diabetes in a cohort of 78 high-risk obese youth age 11 to 17 years presenting to a pediatric endocrinology clinic from 2007 to 2009. Association between self-reported depressive symptom scores using the Center for Epidemiological Studies Depression Scale for Children (CES-DC) and measures above were also explored. Of the 78 participants enrolled in the original study, 44 (56.4%) underwent oral glucose tolerance testing, and 4 (9.1%) were diagnosed with impaired glucose tolerance. None had a confirmed diagnosis of type-2 diabetes over the 6 year study period. Two hour oral glucose tolerance results significantly correlated with the initial HbA1c (r=.470, p=.007), the sum of insulin levels (r=.518, p=.001), and HOMA-IR (r=.429, p=.007). The insulin total correlated with HOMA-IR (r=.553, p=.001). The incidence of self-reported depressive symptoms was high in 35 (49 %) participants (n=71). None of the measures of impaired glucose metabolism correlated with depression scores. These results indicate that even with a small sample of obese youth, 78 % met criteria for insulin resistance. The HbA1c correlated with 2-hour glucose tolerance test results. Glucose tolerance testing is used clinically for confirmatory diagnosis of impaired glucose tolerance and type-2 diabetes which support the use of HbA1c for screening youth. Despite lack of association between depressive symptoms and impaired glucose metabolism, 49% reported symptoms of depression with 11% moderate or severe. It would be prudent to screen all obese youth for depressive symptoms as this may impact their ability to implement lifestyle changes. Future research is needed with a larger prospective sample of high-risk obese youth to identify those more likely to develop type-2 diabetes and benefit from lifestyle interventions.