First responders working at ground zero in New York City following the 9/11 terrorist attacks on the World Trade Center were exposed to cement dust, smoke, glass fibers, and heavy metals.

Research presented at the American Society of Nephrology Kidney Week 2013 in Atlanta, GA say  exposure to high levels of such particulate matter caused significant damage to first responders' kidneys.

But aren't first responders generally exposed to particulate matter? Where there's smoke, there's fire, and that is where you find firefighters. And where there is smoke, you also find particulate matter.

The same team previously demonstrated abnormalities in heart and lung in first responders to 9/11. In this latest study, the investigators evaluated 183 consecutively enrolled first responders from the WTC–CHEST Program, a subset of the World Trade Center Clinical Center of Excellence. Participants provided information about particulate matter exposure, and exposure score was calculated based on proximity to Ground Zero, time of arrival, and duration of exposure. 

Kidney tests demonstrated a linear trend between level of exposure to particulate matter and measures of poor kidney function. Participants with the highest exposure to particulate matter had significantly worse kidney function than those with low exposure.

"We observed a statistically significant independent relationship of high exposure to particulate matter with albuminuria in this cohort after controlling for pertinent risk factors," reported lead author Mary Ann McLaughlin, MD (Icahn School of Medicine at Mount Sinai). "This novel finding paves the way for future studies of environmental exposures and inflammation in the pathogenesis of albuminuria."