The study authors, Dr Murray Mittleman and colleagues at the Beth Israel Deaconess Medical Center in Boston, measured kidney function using a recognised test called the glomerular filtration rate (GFR).
Those patients who lived closest to a major road had the lowest GFR even after taking account of factors such as age, sex, race, smoking and other underlying medical conditions.
The difference in GFR between these patients and those who lived further away from traffic pollution was comparable to a reduction in GFR associated with being four years older, the researchers say.