Higher socioeconomic status is not associated with equal reductions in rates of type 2 diabetes and obesity across racial and ethnic groups in the United States, according to a new study published July 8, 2026, in the open access journal PLoS One by Sara Cromer of Harvard Medical School, USA, and colleagues.
Adverse socioeconomic status (SES) is associated with adverse health outcomes, and many researchers, clinicians, and risk calculators assume that improvements in SES confer equivalent health benefits across population groups.
In the new study, researchers analyzed data from 54,991 adult participants in the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018 along with 404,990 participants in the All of us (AoU) cohort. They assessed associations between educational attainment, income, and prevalence of type 2 diabetes (T2D) and obesity.
Age-adjusted rates of T2D and obesity were generally highest among lower SES participants and among non-Hispanic Black, Mexican American, Other Hispanic, and Other/Multiracial participants. When examining how rates varied with SES in different racial and ethnic groups, using adjusted models, the researchers found that higher educational attainment was associated with a 12% reduction in T2D prevalence among non-Hispanic White participants (OR 0.88, 95% CI 0.85–0.91) but only a 4.9% reduction in Blacks, 6% 0.9% Black, 0.9% Black participants are CI 0.92–0.99). Similarly, higher income was protective against obesity among non-Hispanic White participants (OR 0.97, 95% CI 0.95–0.996), but was associated with higher rates of obesity among non-Hispanic Black participants (OR 1.05, 95% CI 1.01–1.08). Results also vary by dataset and SES measure used—education is associated with metabolic disease differently than income, for example, and these related measures capture different risks.
The cross-sectional design of the study means that it cannot prove causality, and the AoU cohort is subject to selection bias, with non-Hispanic Asian participants in particular showing very high levels of educational attainment. Despite these limitations, the authors conclude that the direction, magnitude, and form of the association between SES and metabolic disease are heterogeneous among US racial and ethnic groups, and that treating these associations as uniform may obscure important differences, particularly among minority populations.
Sarah Cromer adds:Although improvement in education or income is associated with lower rates of diabetes and obesity on average, the rate of improvement varies significantly by race. Overall, blacks, Hispanics, and Asians in the US have reduced protective effects of higher education and income than whites.”
“We have known for many years that reduced education and income are associated with worse health outcomes. Understanding how education and income interact with health across communities is increasingly important right now because, in efforts to promote precision medicine but also prevent race-based medical decision-making, medical risk calculators are beginning to include measures such as education and income to help doctors make treatment recommendations. If we don’t have a good understanding of how these factors affect health, or if we ignore differences between communities, these calculators can lead to worsening health inequalities.”
Chirag Patel adds:Socioeconomic status alone does not capture the full picture of health risk, and how we measure it matters. These findings set a clearer standard for how researchers should capture and report these variables so that predictive tools are accurate in all patients they are intended to serve.“
