Living less than 50 meters from a major roadway resulted in significantly reduced kidney function when compared to those living further than 1000 meters. The study was conducted by Harvard University and Beth Israel Deaconess Medical Center in Boston, MA and included patients who had previously experienced a stroke. Previous studies have shown increased risk of heart attack and stroke when living near busy roadways. Kidney function was determined using the blood test known as eGFR. Scores were 3.9 mL/min/1.73 m2 lower for those living the closest to busy highways. To put this into context, authors stated this reduction in kidney function was equivalent to a 4 year increase in aging. The 'Read More' section below contains a quote of concern from study authors.
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"Ambient air pollution is a recognized risk factor for cardiovascular disease.[1] There is evidence that living near a major roadway contributes to the incidence of vascular disease[1, 2] including increased cardiovascular mortality, [3–5] acute myocardial infarction, [6] adverse prognosis among early survivors of acute myocardial infarction, [7] atherosclerosis as indicated by increased coronary artery calcium[8] and peripheral arterial disease, [9] and deep vein thrombosis.[10]"
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ABSTRACT
Background
Living near major roadways has been associated with increased risk of cardiovascular events, but little is known about its impact on renal function.
Methods
We calculated estimated glomerular filtration rate (eGFR) for 1103 consecutive Boston-area patients hospitalized with acute ischemic stroke between 1999 and 2004. We used linear regression to evaluate the association between eGFR and categories of residential distance to major roadway (0 to ≤ 50, 50 to ≤ 100, 100 to ≤ 200, 200 to ≤ 400, 400 to ≤ 1000, and >1000 m) adjusting for age, sex, race, smoking, comorbid conditions, treatment with angiotensin-converting enzyme inhibitor, and neighborhood-level socioeconomic characteristics. In a second analysis, we considered the log of distance to major roadway as a continuous variable.
Results
Patients living closer to a major roadway had lower eGFR than patients living farther away (Ptrend=0.01). Comparing patients living 50 m versus 1000 m from a major roadway was associated with a 3.9 mL/min/1.73 m2 lower eGFR (95% CI: 1.0, 6.7; p=0.007); a difference comparable in magnitude to the reduction in eGFR observed for a 4 year increase in age in population-based studies. The magnitude of this association did not differ significantly across categories of age, sex, race, history of hypertension, diabetes, or socioeconomic status.
Conclusions
Living near a major roadway is associated with lower eGFR in a cohort of patients presenting with acute ischemic stroke. If causal, these results imply that exposures associated with living near a major roadway contribute to reduced renal function, an important risk factor for cardiovascular events.