Differences in Comorbidities and Diagnosis of Early-Onset Type 2 Diabetes by Ethnicity

A black woman with cancer is meeting with her doctor. The doctor is a mixed-race man of Asian and Indian descent. The two individuals are seated next to each other. The medical professional is using a stethoscope to check the patient’s heart and lungs. The patient is wearing a bandana to hide her hair loss from chemotherapy treatment.
In early-onset T2D, how do comorbidities such as BMI and cardiovascular disease compare in Black vs White patients?

Compared with White people, those who are Black have higher cardiovascular risk when early-onset type 2 diabetes (T2D) develops, according to the results of a study published in Diabetes Care.

Studies have shown an increase in the incidence of early-onset T2D diagnosis and a greater risk for T2D among Black people when compared with White people, but the evaluation of ethnicity-specific temporal trends of early-onset T2D diagnosis and the impact of comorbidities at the time of diagnosis had not yet been conducted.

To investigate and compare the trends in early-onset T2D diagnosis of Black and White people as well as the trends of various risk factors at the time of T2D diagnosis, data from 606,440 individuals aged 18 to 70 years who were diagnosed with T2D between 2000 and 2018 were analyzed. Atherosclerotic cardiovascular disease (ASCVD) was defined by the presence of a clinical diagnosis of ischemic heart disease.

Over the past 2 decades, the rate of T2D diagnosis among Black patients within the age groups 18 to 39 and 40 to49 years has consistently been higher than that of their White counterparts (P <.01). The proportion of both Black and White patients diagnosed with T2D before 50 years of age increased significantly from 2012 to 2018 (P <.05).

Black patients had significantly higher mean hemoglobin A1c (HbA1c) than White patients across all age groups. Although no difference was seen in other age groups, Black patients 18 to 39 years of age had significantly higher body mass index (BMI) than their White counterparts (P =.02).

MACE-3 refers to 3-point major adverse cardiovascular events — heart failure, myocardial infarction, or stroke. Black patients had a significantly higher risk for MACE-3 compared with White patients across all age groups, with the youngest age group having the highest relative risk (hazard ratio [HR], 1.63; 95% CI, 1.42-1.88) and the lowest relative risk observed in the oldest age group (HR, 1.11; 95% CI, 1.06-1.15).

Taken as a whole, the results of this study illustrated the increasing burden of early-onset T2D and the increased risk of MACE-3 for Black patients. Understanding the trends in diagnosis of early-onset T2D and the differences in the prevalence of related comorbidities among people of different ethnicities may improve healthcare practitioners’ ability to detect and manage this disease.

Limitations of this study include the use of electronic medical records, which may have resulted in errors in data collection due to condition coding, and the fact that the database did not link directly to hospitalized data.

Future investigation into potential explanations for the differences between ethnicities observed in this study are warranted.


Dibato JE, Montvida O, Zaccardi F, et al. Association of cardiometabolic multimorbidity and depression with cardiovascular events in early-onset adult type 2 diabetes: a multiethnic study in the US. Published online November 11, 2020. Diabetes Care. doi: 10.2337/dc20-2045