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

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.