Diabetes Prevalence and Incidence Inequality Trends Among U.S. Adults, 2008–2021

Abstract

This study examined national trends in age, sex, racial and ethnic, and socioeconomic inequalities for diagnosed diabetes prevalence and incidence among U.S. adults from 2008 to 2021. Adults (aged ≥18 years) were from the National Health Interview Survey (2008-2021). The annual between-group variance (BGV) for sex, race, and ethnicity; and the slope index of inequality (SII) for age, education, and poverty-to-income ratio along with the average annual percentage change (AAPC) were estimated in 2023 to assess trends in inequalities over time in diabetes prevalence and incidence. For BGV and SII, a value of 0 represents no inequality, whereas a value further from 0 represents greater inequality. On average over time, poverty-to-income ratio inequalities in diabetes prevalence worsened (SII= -8.24 in 2008 and -9.80 in 2021; AAPC for SII= -1.90%, p=0.003), whereas inequalities in incidence for age (SII=17.60 in 2008 and 8.85 in 2021; AAPC for SII= -6.47%, p<0.001), sex (BGV=0.09 in 2008, 2.05 in 2009, 1.24 in 2010, and 0.27 in 2021; AAPC for BGV= -12.34%, p=0.002), racial and ethnic (BGV=4.80 in 2008 and 2.17 in 2021; AAPC for BGV= -10.59%, p=0.010), and education (SII= -9.89 in 2008 and -2.20 in 2021; AAPC for SII=8.27%, p=0.001) groups improved. From 2008 to 2021, age, sex, racial and ethnic, and education inequalities in the incidence of diagnosed diabetes improved but persisted. Income-related diabetes prevalence inequalities worsened over time. To close these gaps, future research could focus on identifying the factors driving these trends, including the contribution of morbidity and mortality.