Scientists have found that people, who live closer to a major road, may have their kidney function impaired.
The scientists based their findings on more than 1100 adults who had sustained a stroke between 1999 and 2004 and had been admitted to hospital in the greater Boston area of Massachusetts in the US.
On admission, each patient's serum creatinine was measured. This is a by-product of muscle metabolism and is filtered out of the body by the kidney, known as the glomerular filtration rate or GFR. The GFR is therefore an indicator of the health of the kidneys and how well they are working.
50 percent patients lived within 1 km of a major road, with the rest living between 1 and 10 km away.
After taking account of influential factors, like age, sex, race, smoking, underlying conditions, treatment for heart conditions, and neighbourhood affluence, patients who lived closest to a major road had the lowest GFR.
Those who lived 50 metres away had a GFR of 3.9 ml/minute/1.73 m2 lower than those who lived 1 km away.
The researchers calculated that a reduction in proximity to a major road from 1 km to 50 metres may be associated with a 4 percent higher rate of cardiovascular death and 1 percent increased risk in death from all causes.
Air pollution caused by traffic is associated with a raised risk of stroke and heart attack, as a result of inflammation, artery narrowing as a result of plaque build-up, and changes to peripheral arteries.
The researchers added that the kidneys are highly susceptible to the build-up of arterial plaque.
