Kidney problems linked to traffic fumes
The US investigators who discovered a link in 1,100 patients believe traffic pollution could harm the arteries that supply the kidneys.
"Since we know traffic pollution increases the risk of heart disease, the message of this study - that traffic pollution might damage the kidneys - is perhaps to be expected.
"The responsibility to reduce traffic pollution falls on everyone, and this study is yet another reason - as if we needed one - to travel on foot or bike where possible."
But he cautioned that the current study only showed a link - it does not prove living next to a road definitely affects kidney function.
The researchers were unable to control for all socio-economic factors and all of the patients in the study had recently suffered a stroke.
They say more studies looking at different groups of people are needed to confirm the findings.