Trends in Diagnosed and Undiagnosed Diabetes Among Adults in the U.S., 2005–2016

Accurate surveillance of diabetes is crucial for establishing relevant policies of diabetes prevention and control. Previous studies estimated the trends in diabetes among adults in the U.S.; however, many did not consider results of the oral glucose tolerance test (OGTT) (1), and those studies that included the OGTT results reported a higher prevalence of undiagnosed diabetes (2). Capitalizing on the OGTT data since 2005–2006 in the National Health and Nutrition Examination Survey (NHANES), we assessed the trends in diagnosed and undiagnosed diabetes among adults in the U.S. from 2005 to 2016. NHANES is a cross-sectional survey with a stratified, multistage probability design to assess the health status of the noninstitutionalized civilian population in the U.S. (3). A household interview was conducted to collect health-related information including demographic characteristics and medical history. A subset of participants was randomly selected to provide a fasting blood sample and take an OGTT at the mobile examination center. Sample weights were constructed to account for nonresponse and oversampling. The survey was approved by the research ethics review board of the National Center for Health Statistics. Written informed consent was obtained from each participant. This investigation included nonpregnant participants aged 20 years or older, recruited from 2005–2006 to 2015–2016 cycles, who had information on self-reported diagnosed diabetes or laboratory results of fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), and 2-h plasma glucose (2-h PG). We calibrated plasma glucose measurements to …