Medication type modifies inflammatory response to traffic exposure in a population with type 2 diabetes

The association between residential traffic exposure and change in C-reactive protein over 2-years was evaluated using multivariate linear regression including interaction models for traffic and diabetes medication use/type (insulin vs. oral hypoglycemic agents (OHAs)). The study population was Puerto Rican adults (n = 356) residing in greater Boston with type 2 diabetes. Traffic was characterized as proximity to roads with >20,000 weekday traffic volumes, and multi-directional traffic density. Increases in CRP concentration were significantly associated with residence ≤100 m of a roadway (p = 0.009) or near multiple roadways (p < 0.001), vs. further away, for individuals using insulin in stratified models, with consistent results in interaction models (p = 0.071 and p = 0.002). CRP was significantly lower with highest traffic density exposure in stratified (p = 0.03) and interaction models (p = 0.024) for individuals using OHAs. Individuals on insulin experienced increased CRP concentrations with traffic exposure over a 2-year study period, while those using OHAs did not experience increases. - Highlights: • T2D medication effect on traffic exposure and CRP was examined longitudinally. • Participants were older Puerto Rican adults (n = 356) living in the Boston, MA area. • Major road proximity and traffic density were assessed for each residential address. • Those on insulin showed significantly increased CRP with increased traffic exposure. • Those on oral hypoglycemic agents did not show increased CRP with traffic exposure. - Individuals on insulin were most vulnerable to traffic-related increases in CRP, while those on OHAs did not experience increases