Trends and disparities in diabetes and prediabetes among adults in the United States, 1999-2018

Abstract

<p><strong>Objective: </strong>The aims of the study were to describe the up-to-date trend of total, diagnosed, and undiagnosed diabetes and prediabetes, assess their associated disparities among population subgroups, and examine their relationship with sociodemographic factors among adults in the United States.</p><p><strong>Study design: </strong>This was a cross-sectional study from a nationally representative sample of US adults (aged ≥20 years) who participated in the National Health and Nutrition Examination Survey.</p><p><strong>Methods: </strong>Diagnosed diabetes was defined as a self-reported previous diagnosis of diabetes by a physician or any other health professionals (other than during pregnancy). Undiagnosed diabetes was defined as elevated levels of fasting plasma glucose (≥126 mg/dL) or HbA_1c (≥6.5%). Total diabetes included those who had either diagnosed or undiagnosed diabetes. Prediabetes was defined as an HbA_1c level of 5.7%-6.4% or a fasting plasma glucose level of 100-125 mg/dL. All estimates were age standardized to the 2010 US census population for age groups 20-44, 45-64, and 65+ years. All analyses accounted for the complex survey design. Logistic regressions were used to conduct the analyses.</p><p><strong>Results: </strong>A total of 21,600 (mean, 47.2 years [SD, 14.7]) individuals were analyzed. From 1999 to 2018, the age-standardized prevalence increased significantly from 9.17% to 14.7% (difference, 5.52%; 95% confidence interval [CI], 2.69%-8.35%; P-trend <0.001) for total diabetes, increased from 6.15% to 11.0% (difference, 4.79%; 95% CI, 2.27%-7.32%; P-trend<0.001) for diagnosed diabetes and remained stable from 3.01% to 3.73% (difference, 0.72%; 95% CI, -0.47% to 1.91%; P-trend = 0.19) for undiagnosed diabetes. The age-standardized prevalence of prediabetes increased significantly from 29.5% to 48.3% (difference, 18.8%; 95% CI, 13.3%-24.4%; P-trend<0.001). Disparities persisted with higher prevalence among adults with obesity and populations that have been marginalized, including racial and ethnic minorities, low income, less educated Americans, and those living in food-insecure household.</p><p><strong>Conclusions: </strong>The prevalence of diabetes and prediabetes increased significantly from 1999 to 2018 among US adults. There are substantial and persistent disparities among racial and ethnic minorities, populations experiencing socio-economic disadvantages, and adults with obesity.<br></p>