Living close to a major road may impair kidney function - increasing the risk of heart disease and stroke - suggests research published online in the Journal of Epidemiology and Community Health and BMJ.com.
The authors based their findings on 1,100 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. Half the patients lived within 1km of a major road, with the rest living between 1 and 1 km away.
After taking account of influential factors, such as age, sex, race, smoking, underlying conditions, treatment for heart conditions, and neighbourhood affluence, those patients who lived closest to a major road had the lowest GFR. Those who lived 50 metres away had a GFR that was 3.9 ml/minute/1.73 m2 lower than those who lived 1000 metres away. This difference is comparable to a reduction in GFR associated with being 4 years older.
The authors calculate that a reduction in proximity to a major road from 1000 metres to 50 metres may be associated with a 4% higher rate of cardiovascular death and a 1% increased risk in death from all causes. Air pollution caused by traffic is associated with an increased 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.