Neighborhood Disadvantage Impacts Type 1 Diabetes

Neighborhood disadvantage may increase inflammation and contribute to poor metabolic control, though racial differences complicate the picture, according to a study published online in PediatricDiabetes.  

“Collectively, the results of this study show that neighborhood disadvantage (CDI) was associated with poor metabolic control (higher HbA1c) in blacks, and with inflammation (higher CRP) in both blacks and whites,” wrote lead author James Hemp, PhD, and colleagues at Louisiana State University Health Sciences Center (New Orleans, LA).

Hba1c levels are often higher in blacks compared to whites, yet the underlying reasons have been difficult to pinpoint. Genetic factors may play a role, but public health research has suggested that social and environmental factors may also be involved. Psychosocial issues like depression can contribute to low medication adherence. Racial differences in obesity and social stressors have also been linked to increased inflammation, which in turn may play a role in insulin resistance, according to background information in the article.

The study included 33 black and 53 white patients aged 5-21 years receiving care in pediatric diabetes clinics at Children’s Hospital, New Orleans, LA. Researchers obtained mean blood glucose for the past 30 days from data downloaded from glucose self-monitors. They also analyzed blood samples for HbA1c and c-reactive protein (CRP), a measure of inflammation. They estimated neighborhood disadvantage by calculating the concentrated disadvantage index (CDI) using patients’ addresses and census data, with a high CDI indicating more disadvantage.

Key results:

• HbA1c: Higher in blacks than whites (10.4% vs 8.9%, P<0.0001)

♦ Tended to be higher in blacks vs whites at all levels of inflammation

• Mean blood glucose (MBG): Higher in blacks than whites (255 mg/dL vs 198 mg/dL, P=0.0002)

• Mean CRP: Not significantly different between blacks and whites (5.27 vs 4.83, P=0.88)

♦ Analyses controlling for race suggested a positive link between CDI and CRP in both blacks and whites

• CDI:  Higher in blacks than whites (0.955 vs -0.617, P<0.0001)

♦ Increased as HbA1c (r=0.40, P=0.0002) and MBG (r=0.35, P=0.0011) increased, unless controlled for by race

♦ Subgroup analysis by race showed CDI was linked to HbA1c in blacks but not whites

• 64% of whites used insulin pumps compared to 9% of blacks

“Differentiating between genetic and environmental effects was not possible. . .due to racial differences in treatment regimen and the lack of significant racial overlap in CDI,” the authors concluded.

They suggested that future studies looking at the genetic and environmental contribution to racial differences in HbA1c should match patients from different racial groups by neighborhood factors and diabetes treatment.  Such studies should also address behavioral factors like depression and treatment adherence, as well as environmental factors like infection and access to health care.

Take-home Points

• The New Orleans study found that HbA1c, mean blood glucose, and neighborhood disadvantage are significantly higher but CRP is similar in pediatric black patients with T1DM, compared to white patients.

• Analyses by race showed neighborhood disadvantage was linked to HbA1c in blacks but not whites.

• Analyses controlling for race suggested a positive link between neighborhood disadvantage and CRP in both blacks and whites.

• Large racial differences in treatment and neighborhood disadvantage complicated interpretation of the data.

Reference: Coulon SJ, et al. Racial differences in neighborhood disadvantage, inflammation and metabolic control in black and white pediatric type 1 diabetes patients. Pediatr Diabetes. 2016 Jan 18. [Epub ahead of print]