Research Highlights Racial/Ethnic Diabetes Disparities Based on Age of Diagnosis

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New research underscores racial/ethnic diabetes disparities in the United States.

Earlier age at diabetes diagnosis among non-Hispanic Black and Mexican American adults can be attributed to a combination of clinical, behavioral, and social factors, researchers writing in JAMA Internal Medicine concluded.

This finding could contribute to observed disparities in diabetes-related microvascular and macrovascular complications and premature mortality, they added.

The prevalence of diabetes has substantially increased in the past 20 years in the United States. It generally occurs at a higher rate among non-Hispanic Black and Hispanic adults than non-Hispanic White adults, and because earlier onset is associated with more negative outcomes, investigators set out to compare self-reported age at diabetes diagnosis based on race/ethnicity in the United States.

The cross-sectional study included data from four 2-year cycles of the National Health and Nutrition Examination Survey. Responses were collected between 2011 and 2018. All participants were at least 20 years old and self-reported a history of diabetes and age of onset.


In addition, “self-reported race/ethnicity was assessed as a social construct to investigate health disparities,” the authors said, while they “determined the proportion of adults in each racial/ethnic group with age at diagnosis of diabetes before age 40, 35, and 30 years.”

All adults with a likely diagnosis of type 1 diabetes were excluded.

Of the included 3022 patients, 1586 were male and the mean (SD) patient age was 61.1 (0.3) years. A total of 946 participants were non-Hispanic White and the overall sample represented 22,844,326 adults.

Analyses revealed:

  • Mean age at diabetes diagnosis overall was 49.9 (95% CI, 49.2-50.7) years
  • Relative to non-Hispanic White adults (mean age, 51.8 years; 95% CI, 50.8-52.9), Mexican American (mean age, 47.2 years; 95% CI, 46.1-48.4) and non-Hispanic Black adults (44.9 years; 95% CI, 43.4-46.4) reported a significantly younger mean age at diagnosis, but non-Hispanic Asian adults did not (mean age, 50.5 years; 95% CI, 48.4-52.6)
  • The weighted proportion of adults with diabetes diagnosed before age 40 years was greater among Mexican American adults (35%) and non-Hispanic Black adults (25.1%) compared with non-Hispanic White adults (14.4%) (P ≤ .001)
  • A similar pattern in age at diabetes diagnosis was observed in a sensitivity analysis, including all adults with self-reported diabetes

Overall, “the mean age at diabetes diagnosis was 4 to 7 years earlier in non-Hispanic Black and Mexican American adults than in non-Hispanic White adults,” the authors wrote. Over a quarter of non-Hispanic Black and Mexican American patients received the diagnosis before age 40.

The researchers noted the lack of differences observed between non-Hispanic White and non-Hispanic Asian populations could mask heterogeneity across Asian subgroups, marking a limitation to the study. The use of self-reported data is also subject to recall bias and does not include undiagnosed diabetes.

Based on the findings, “there may be benefit to initiating intensive lifestyle changes starting earlier in adulthood,” the researchers concluded. “Efforts to prevent and manage diabetes earlier in the life course may help reduce the substantial premature morbidity and mortality associated with diabetes.”


Wang MC, Shah NS, Carnethon MR, O’Brien MJ, Khan SS. Age at diagnosis of diabetes by race and ethnicity in the United States from 2011 to 2018. JAMA Intern Med. Published online September 7, 2021. doi:10.1001/jamainternmed.2021.4945