Exposure to secondhand smoke can elevate the risk for chronic kidney disease, a local study found.

Park Jung-tak, a professor at nephrology department of Yonsei University College of Medicine, and his research team published a paper, “Secondhand Smoke and CKD (chronic kidney disease),” on the online issue of the Clinical Journal of American Society of Nephrology on Thursday.

According to the study, the risk of developing chronic kidney disease surged after two or three days of exposure to secondhand smoke.

It is well known that smoking causes a variety of illnesses, but it is the first time a study confirmed that nonsmokers’ exposure to secondhand smoke alone raises the risk of chronic kidney disease.

The researchers studied about 130,000 nonsmokers in three groups: those who had no exposure to secondhand smoke; those who had the exposure for less than three days a week; and those who had it for more than three days a week.

The result showed that the hazard ratio of the risk for chronic kidney disease development stood at 59 percent in people who had less than three days a week, and 66 percent in people who had more than three days a week, compared to the group with no exposure.

“Smoking is restricted in many public places, but many people are still exposed to secondhand smoke at home or work,” Park said. “Once kidney function is damaged, it is difficult to restore it. So, we should care for each other not to let nonsmokers be exposed to secondhand smoke and supplement the related system.”

The study, introduced by global news media including The New York Times, has raised an alert on harmful effects of secondhand smoke.