Genetics, Socioeconomic Factors Each Tied to Diabetes and Obesity

Genetic and socioeconomic factors were each independently associated with increased risk for both type 2 diabetes (T2D) and obesity, according to a biobank study of Americans of European ancestry.

Among more than 27,000 white individuals in the Mass General Brigham Biobank, those in the highest genetic risk quintile were 5.7 times more likely to have T2D and 4.8 times more likely to have obesity compared with those in the lowest risk quintile, reported Sara Cromer, MD, of Massachusetts General Hospital in Boston.

Overall, people in both the highest genetic risk and socioeconomic status (SES) risk quintiles were 15.7 and 9.7 times more likely to have T2D and obesity, respectively, than those in the lowest risk quintiles (P<0.05 for both), according to findings presented at the virtual American Diabetes Association Scientific Sessions.

"Both of these factors should be considered when counseling patients about their individual risk and when considering interventions ... at the population level," Cromer said during her presentation.

In adjusted models, various factors were independently associated with T2D risk:

• Older age (OR 1.05, 95% CI 1.05-1.05)
• Male sex (OR 1.63, 95% CI 1.50-1.78)
• Genetic risk (OR 1.95 per SD, 95% CI 1.87-2.04)
• SES risk (OR 1.26 per SD, 95% CI 1.20-1.32)

Similarly, these factors were independently associated with obesity risk:

• Older age (OR 1.01, 95% CI 1.01-1.02)
• Male sex (OR 1.15, 95% CI 1.09-1.21)
• Genetic risk (OR 1.79 per SD, 95% CI 1.75-1.84)
• SES risk (OR 1.20 per SD, 95% CI 1.17-1.24)

For their study, researchers examined population data on 27,224 patients with available genetic information using electronic health care data and the Mass General Brigham Biobank. Mean age of participants was 61, while 53% were female.

To start, Cromer's team looked at several census tract-level SES measures in Boston, including education, income, and employment status. Here, scoring high on the social deprivation index (SDI) and lower population levels of college education strongly correlated with T2D and obesity, after adjusting for age and sex.

T2D status was determined based on a machine-learning phenotype, and obesity based on the phenotype or a maximum BMI ≥30. Genetic quintiles were determined via global extended polygenic risk scores.

For diabetes, those in the highest risk quintiles for college degree preponderance and for SDI were, respectively, 1.7 times and 1.7 times more likely to have T2D than those in the lowest risk quintiles. For obesity, these measures were 2.3 times and 1.9 times more likely for the highest versus lowest risk quintiles.

Researchers did not find any interaction between SES and genetic risk, Cromer noted. So, for example, living in a neighborhood with less SES risk does not help people overcome "bad genetics" when it comes to T2D or obesity risk, she told MedPage Today.

Cromer's team is currently conducting similar analyses of their Black and Hispanic biobank populations, she told MedPage Today. They plan to eventually conduct meta-analysis of the entire sample, featuring all the ethnicities and races. This first study was limited to white participants because the biobank population is about 15-20 times more white than either Black or Hispanic, she said, and because the available instruments are more reliable to assess those with European ancestry.

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