When should children who have a family history of either type 1 or type 2 diabetesbe screened for prediabetes?
When should children who have a family history of either type 1 or type 2 diabetesbe screened for prediabetes? What screening criteria are recommended?-- MDScreening for type 1 diabetesand screening for type 2diabetes are very differentissues.Type 1 diabetes.Screening for risk of type 1 diabetesis done in the context of researchstudies and is a critical tool in furtheringour understanding of the naturalhistory and pathogenesis of thedisease. In this setting, both primaryautoantibody screening and genetic(HLA) screening are performed.When you consider screening fortype 1 diabetes, bear in mind thatthere is currently no effective interventionif autoantibodies associatedwith high risk are detected in anasymptomatic individual. Moreover,the risks of screening (primarily anxietyon the part of both child andparents) may outweigh the benefits(possible early diagnosis, avoidanceof severe diabetic ketoacidosis).In children with a strong familyhistory of type 1 diabetes, primary autoantibody screening is recommendedto identify those who are at risk. However, keep in mind that 85% of childrenwith newly diagnosed type 1 diabetes have no family history of the disease.1For children in the general population, the newer strategy of primary genetic(HLA) screening at birth, followed by antibody screening in a researchsetting for those identified as high risk, makes more sense.In first-degree relatives of persons with type 1 diabetes, who have ahigher risk of type 1 diabetes (1/20 vs 1/300 in the general population), riskcan be determined by measuring antibodies to islet cells, antibodies to glutamicacid decarboxylase, antibodies to insulinoma-associated antigen, andautoantibodies to insulin. Such a testing program is being offered as partof TrialNet, funded by the NIH. Participation is free, and more informationcan be obtained by calling 800-425-8361.In an asymptomatic child whose parents are concerned about type 1diabetes, there is no reason to perform any screening studies other thangenotyping and antibody tests. Consider measurement of the fasting bloodglucose level; 2-hour postprandial glucose level; and perhaps hemoglobin A1c level only if polydipsia, polyphagia, or polyuria develop, or if the childhas documented high-risk alleles or positive antibody tests.Type 2 diabetes. Screening for type 2 diabetes is quite different. Clearly,significant genetic influences are involved in the development of this disease;African American, Hispanic, and Native American children are at increasedrisk. However, the main determinants of type 2 diabetes risk remain the simpletriad of poor diet, insufficient exercise, and obesity. In children who areobese, who have physical evidence of insulin resistance (such as acanthosisnigricans [Figure]), or who have a strong family history of type 2 diabetes,screening for prediabetes and the metabolic syndrome is clearly indicated.Initial screening of an asymptomatic child at risk for type 2 diabetesincludes a fasting lipid profile; measurement of blood glucose and insulinlevels; a 2-hour postprandial glucose level determination; and careful documentationof blood pressure, height, and weight. If the child has a fastingblood glucose level of 126 mg/dL or greater or a postprandial glucose levelof more than 200 mg/dL, he or she already has diabetes. However, mostchildren who are screened will likely either have normal blood glucose levelsor show evidence of impaired glucose tolerance (2-hour postprandialglucose level greater than 140 mg/dL) or an impaired fasting glucose level(greater than 100 mg/dL).Children with impaired glucose tolerance or an impaired fasting glucoselevel require formal oral glucose tolerance testing and close follow-up.In addition, those whose blood pressure or lipid levels are elevated (bloodpressure higher than the 95th percentile for age, gender, and height; lowdensitylipoprotein cholesterol level greater than 130 mg/dL; high-densitylipoprotein cholesterol level less than 40 mg/dL) are at risk for the metabolicsyndrome. Consider early initiation of lipid-lowering drugs (statins canbe used in patients as young as 10 years) and antihypertensive therapy. Immediatereferral to a nutritionist and initiation of a structured exercise regimenis indicated as well.Lifestyle changes that encourage weight loss and exercise are the mosteffective way to avoid the eventual development of diabetes in these children.However, early use of metformin can also help delay the onset of diabetesin children with impaired glucose tolerance.-- Michael Haller, MD
Fellow in pediatric endocrinology
University of Florida School of Medicine
-- Desmond Schatz, MD
Professor and Associate Chair of Pediatrics
Medical Director, Diabetes Center
University of Florida School of Medicine
Morales A, She J, Schatz D. Genetics of type 1 diabetes. In: Pescovitz O, Eugster E, eds.
Pediatric Endocrinology:Mechanisms, Manifestations, and Management.
New York: Lippincott, Williams & Wilkins; 2004.