Residential traffic exposure, inflammation and blood pressure in older adults in greater Boston, Massachusetts

Traffic exposure has been shown to increase the risk of cardiovascular disease through pathways that largely overlap with those of conventional risk factors. Systemic inflammation and elevated blood pressure are cardiovascular risk factors elevated in people age 50+ as well as in those with diabetes and obesity. This cross-sectional study of 1017 older adults residing in the greater Boston area assessed inflammatory and blood pressure response to residential traffic exposure in complex and heterogeneous urban traffic environments. Exposure characterization methods were developed to capture both localized impacts of residing near (<200 meter) major roads and intra-urban variation in traffic density at the level of Traffic Analysis Zones (TAZ), representing a new application of a well-established transportation planning tool. Traffic density was significantly associated with C-reactive protein (CRP), a measure of inflammation, for the full population and traffic proximity and density were associated with CRP for individuals with obesity and without diabetes. Traffic proximity measures were significantly associated with pulse pressure increases for all individuals, more so for those with obesity or diabetes living near multiple roads. Medications taken by the 30% of individuals in the study with diabetes were found to significantly interact with traffic exposures, increasing CRP for those on insulin and decreasing CRP for those on noninsulin medications.;While cross-sectional in design, this study provides evidence that individuals with obesity, diabetes, and heart disease are more susceptible to the effects of traffic exposure and that traffic exposure may influence the heart and vasculature through its effects on blood pressure and inflammation. Interactions between traffic exposure and diabetes medications are new findings for this vulnerable population which require further investigations to evaluate prospectively whether certain medications confer any protective effects from traffic exposure, as well as any possible impacts on disease progression for diabetes and cardiovascular outcomes. Growing evidence of the adverse effects of traffic exposure points to the need for transportation planners and health scientists to work in concert to understand and address the magnitude of the problem in their planning regions.