WASHINGTON (Reuters) - Tiny amounts of lead are common in the blood of U.S. teenagers and may be damaging their kidneys, U.S. researchers reported on Monday.
They found evidence of early kidney damage in children with lead levels far below what is normally considered dangerous and said this could lead to kidney disease in later life.
“To our knowledge, this is the first study to show that very low levels of lead may impact kidney function in healthy children, which underscores the need to minimize sources of lead exposure,” Dr. Jeffrey Fadrowski of Johns Hopkins University in Baltimore, who led the study, said in a statement.
Even though sources of lead have been drastically cut in the United States, the metal may still be damaging the health of some people, Fadrowski’s team reported in the Archives of Internal Medicine.
They studied test results from 769 adolescents aged 12 to 20 who took part in the Third National Health and Nutrition Examination Survey from 1988 to 1994.
When divided into four equal groups, those in the quarter with the highest lead levels had evidence of slowing kidney function.
“Our findings were particularly striking because we saw slightly decreased kidney function in healthy children without conditions that could account for it, and this could spell more kidney trouble down the road as these children get older or if they acquire additional risk factors for kidney disease, such as high blood pressure and diabetes,” said Dr. Susan Furth of Johns Hopkins Children’s Center, who worked on the study.
The teens in the study had a mean lead level of 1.5 micrograms per deciliter, considered safe by the U.S. Centers for Disease Control and Prevention. The CDC’s level of concern for lead is 10 micrograms per deciliter of blood.
The youngsters with lead levels above 2.9 had slower kidney function. They were also more likely to come from poor families with lower education levels.
The researchers noted that 26 million Americans have chronic kidney disease, which can be caused or worsened by high blood pressure.
Lead exposure has decreased substantially in the United States, primarily due to measures including the 1996 ban on lead in gasoline and a 1978 phaseout of lead in paint.
But most of the U.S. general population still has detectable blood levels, the researchers added.
“Current exposure sources include industry, lead paint, folk remedies, glazed pottery, candy, and drinking water in some urban areas, and certain populations continue to experience high lead exposure, in particular, inner-city children and adults living in areas of low socioeconomic status.”
They called for better monitoring of both lead and kidney function in children.
SOURCE: Archives of Internal Medicine, January 11, 2010.