Traffic exposure in a population with high prevalence type 2 diabetes--do medications influence concentrations of C-reactive protein?

Abstract

Type 2 Diabetes (T2D) and particulate air pollution are associated with inflammatory dysregulation. We assessed the modifying effects of diabetes medications on the association of C-reactive protein (CRP), a marker of inflammation, and traffic exposure in adults with T2D (n = 379). CRP concentrations were significantly positively associated with residence ≤100 m of a roadway, >100 m and ≤200 m of a roadway and increased traffic density for individuals using insulin. For individuals using oral hypoglycemic medications (OHAs), CRP was significantly negatively associated with residence >100 m - ≤200 m of a roadway and multiple roadway exposure in an interaction model. Among people with diabetes, individuals on insulin appear to be most vulnerable to the effects of traffic exposure. Disease severity among insulin users may promote the pro-inflammatory response to traffic exposure, though diabetes medications may also modify the response. Possible anti-inflammatory effects of OHAs with traffic exposure merit further evaluation.

Conflict of interest statement

Disclosures

The authors have declared they have no competing interests.

Copyright © 2010 Elsevier Ltd. All rights reserved.

Figures

Figure 1

Figure 2. Percent difference in C-reactive protein among individuals using only OHAs and using insulin (a) and using no diabetes medications (b) and 95% CI associated with traffic indices for complete study group and subgroups

≤ 100 = location of residence less than or equal to100 meters of a roadway with more than 20,000 vehicles per day; >100 - ≤200 location of residence between 100 and 200 m; 1 roadway= location of residence within 200 m of roadway with more than 20,000 vehicles per day; 2+roadways = location of residence within 200 m of 2 or more of these roadways; DenseLevel2, DenseLevel3 and DenseLevel4 = Raster-based traffic density levels.